00:00:00
if you sit for 10 hours a day compared to 9 hours a day it's about a 10% increased risk of dementia if you sit
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for 12 hours a day it's about a 60% increased risk of dementia 60% yes so
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it's a problem that we have to deal with David reand professor of human evolutionary biology exercise physiology
00:00:19
and Neuroscience at the University of Southern California we are dealing with brain health problems that are only
00:00:25
going to increase as our population ages and healthy aging is linked to three behaviors diet physical activity and
00:00:32
social connections for example people who have stronger social connections tend to have better brain outcomes than
00:00:38
people who don't does excessive alcohol use to shrink the brain yes over one drink per day is associated with
00:00:44
negative Health outcomes sleep is the other one that's a big factor in cognitive decline right it is less sleep
00:00:50
and lots of sleep are both associated with higher risk is there a optimal amount of exercise physical activity
00:00:56
guidelines are 150 minutes per week but only 25 % of adults in the US meet those
00:01:01
guidelines with older adults doing 2 to four minutes per day two to four but there are these small activities that
00:01:07
provide big benefits that generate new neurons and those neurons get integrated into key parts of the brain number one
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is remote work is dangerous it's natural for the human body I'm concerned about
00:01:20
physical health what's the Practical advice to people that work at home that is realistic for us if you combine with
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it will literally change your life I think this is fascinating I looked at
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the back end of our YouTube channel and it says that since this channel started 69.9% of you that watch it frequently
00:01:41
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00:01:46
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00:01:52
explain and I promise if you do that to return the favor we will make the show
00:01:57
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00:02:04
[Music]
00:02:09
deal David if you had to summarize the essence of what your work shines Al
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light on and what it intends to help us understand as human beings how would you summarize that what my work has been
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focused on is uh understanding how and why physical activity especially and
00:02:30
lifestyle behaviors in general can impact health and most specifically impact the health of our brains um and I
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think that you know we are dealing with um brain health problems that are only
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going to increase as our population ages uh so we have uh we have six million
00:02:51
people in the US today that are diagnosed with Alzheimer's disease or other related dementias that's projected
00:02:57
to grow to around 13 million people over the next 25 years or so um it's we're
00:03:03
projected to have 150 million people diagnosed with dementia worldwide over the next 30 years or so um so it's a
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problem that we have to deal with and I my work has been focused on ways that we can prevent these diseases that are
00:03:17
associated with aging why does the brain matter and I say this in part because I think for most of my life I just assumed
00:03:25
you know I understand muscles I can go to the gym and work on my muscles but the brain I just thought is this like piece of tofu in between my skull that I
00:03:32
have very little control over yeah I mean I think that is that was the prevailing view for a long time that you
00:03:38
know we grow our brains uh as children and during adolescence and by the time you're in your 20s your brain has done
00:03:45
all the growing it's going to do and now it's just this Progressive shrinking over the rest of your life and you know
00:03:51
over the last few decades we've realized that's not true actually that you can uh generate new neurons especially in uh
00:03:58
key areas of the brain like the hippocampus that's associated with memory and that that growth of new
00:04:05
neurons may be the key to preventing or staving off these neurodegenerative
00:04:11
diseases that have this big impact on the Aging brain um and so you know if we
00:04:17
can find ways to do that and and what I study is uh kind of doing that through
00:04:23
physical activity and exercise um then we might be able to prevent some of the cognitive decline people experience with
00:04:29
age maybe even saave off or prevent the development of Alzheimer's disease or other dementias what evidence have
00:04:36
scientists got that we can actually grow our brain well that's a great question
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the evidence in humans is uh a little trickier so I can talk more about the evidence from animal models because with
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animal models you can actually look inside the brain and see what's happening after say an exercise intervention so there have now been many
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many studies especially in mice and rats where um researchers have shown that if
00:05:01
you give them access to running wheels or if you have them run on a treadmill that you actually generate new neurons
00:05:09
and those neurons survive and get integrated into key parts of the brain and we focus a lot on the hippocampus um
00:05:16
because it's so important to memory um which is a which is a major aspect of being human is being able to remember
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things and uh researchers have shown very clearly that exercise and physical
00:05:28
activity in these rodent models leads to the birth and survival of new neurons what is a neuron what's a neuron
00:05:36
is the main brain cell um so a neuron is sort of the main cell in your brain
00:05:42
that's responsible for um communication and transmission of information across brain regions and where you said this
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hippocampus thing which is where I know you referenced that it's a sort of Center Point for memory yeah where is
00:05:54
that located in the head so the hippocampus is sort is in the temporal deep in the temporal lobe of the brain
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it looks like a seahorse if you know if it's kind of this curved um curved
00:06:04
object in the brain that plays a big role in different aspects of memory so it plays a big role especially in
00:06:11
working memory which is um keeping things in your memory over the short term that you may need to recall quickly
00:06:18
um and it also plays a big role in the formation of memories of events um that
00:06:23
happen in your life and also in spatial navigation which is a an important part of moving around in the world so it's a
00:06:30
really key part of the brain and it's also one of the parts of the brain that is most effective by neurod degenerate
00:06:37
diseases like Alzheimer's disease so it is a part of the brain that deteriorates in these diseases leading to memory
00:06:45
deficits that have a big effect on your daily life is that the only part of the brain that we're able to sort of
00:06:52
regenerate or is it can the rest of you know I'm thinking about these rats and these mice if we put them under a brain
00:06:57
scan would we see the the mass of the brain increasing question and is it just that
00:07:03
little seahorse hippocampus part or is it the whole brain growing so in in rodent models where uh where researchers
00:07:11
have done sort of this detailed work the hippocampus is where uh mainly where new
00:07:16
neurons have been found associated with exercise in human studies brain effects
00:07:21
have been more widespread so you do see volumetric changes in the hippocampus but you also see volumetric changes or
00:07:29
Pres obervation of brain volume in uh frontal loes which are associated with
00:07:34
executive cognitive function so things like planning and decision making um
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where do we need to begin to understand this relationship that humans have between exercise and their brains
00:07:48
there's got to be a point in history where exercise became I guess Pro survival in a way
00:07:54
where it became sort of imperative for us as a human species to do in order to preserve and extend our cognitive
00:08:01
capacity I guess yeah I mean all animals generally have to move to survive right
00:08:06
they have to move to find food in some way but at some point during human history um our our pattern of movement
00:08:14
shifted pretty dramatically and we think that was around 2 million years ago and at that point we shifted from a more
00:08:20
aplike lifestyle to uh hunting and Gathering lifestyle where our our travel
00:08:27
distances increased drastically so we were moving over you know 20 kilometers
00:08:32
sometimes per day um sometimes longer um and our intensity of movement probably
00:08:38
shifted a bit to higher intensities and so the need to uh be physically active
00:08:44
changed and if we think about the way that our physiology evolved our physiology evolved in this context of
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large levels of physical activity on a consistent basis and so I like to think of that as sort of the normal
00:09:00
um condition for humans and anything else so as we kind of progress into modern times and and many people have
00:09:07
dropped their activity that's actually uh the condition that is quite different from the way that our physiology
00:09:13
functions best and and from the way that our physiology evolved does this mean that if I don't do physical activity my
00:09:21
brain will shrink that's a good question I mean on a on a broad Public Health
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scale uh yes you know levels of physical activity or inactivity is associated
00:09:32
with poor brain health smaller volumes of key brain structures so smaller
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hippoc cample volumes for example and worse cognition overall and greater risk
00:09:43
of dementia and Alzheimer's disease on a personal level it's hard to say specifically right because there's so
00:09:49
many factors that go into your risk of um of dealing with these conditions but
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I can say that the best way for any individual to reduce their risk of cognitive decline is to be physically
00:10:02
active what exactly is going on in my brain then when I'm physically active that's causing my brain to be protected
00:10:08
insulated from things like Alzheimer's and Dementia and in some areas of the brain to actually grow what is what is
00:10:15
actually happening inside a lot a lot of fun things um so I mean one of the things that happens when we exercise is
00:10:21
we increase blood flow to the brain and that helps bring nutrients and and keep
00:10:26
our neurons functioning properly but another thing that happens is that your muscles actually generate proteins
00:10:32
called myokines and those travel to the brain and they uh interact with neurons
00:10:39
in ways that upregulate neurotropins so there's this great neurotropin called brain derived neurotropic factor bdnf
00:10:46
and bdnf acts kind of like a fertilizer for brain cells or for new neurons so bdnf when it's upregulated with exercise
00:10:54
um helps both the birth of new neurons and it helps them to survive and integrate into the processes that
00:11:01
they're that they're meant to work for this suit probably a stupid question but I'm just wondering why the brain just doesn't do that anyway I know it
00:11:07
wouldn't it be nice wouldn't it be nice if I didn't have to exercise for the brain to restore itself in such a way to
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expand it it would be nice in some ways but that's just that's not really the way that our physiology works right so
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you know as I was kind as I was saying if you think of the sort of natural condition of humans as being Physically
00:11:27
Active because that's what we had to to find food and survive then our physiology is adapted to that condition
00:11:36
and over the course of two million years we never had to adapt to low levels of physical activity because it just wasn't
00:11:42
a part of being human and so it's only been in the last you know few hundred
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years that we've seen this rapid decline in activity and that's just not enough
00:11:54
time to see that sort of adaptation occur what happened a couple hundred years ago that caused this decline in
00:12:01
physical activity was there like a certain invention or something was there a change in cultural understanding I mean I think think start with the
00:12:07
Industrial Revolution okay as we as we mechanize and we find ways to um to
00:12:13
reduce um our the the need to uh be physically active to gain access to food
00:12:19
to survive um and then as as we move on you know in the last 50 60 70 years we
00:12:26
start to see a a lot more office jobs right we start to see changes in our work life that reduce activity patterns
00:12:33
throughout the day cars I guess cars so in terms of commuting Leisure Time what
00:12:40
do we what do most people do during their Leisure Time the couch is really comfortable our screens are really
00:12:46
enticing TV screens but now phone and computer and all these things and so we
00:12:52
end we end up sitting a lot do you have the stats on the increase in sedentary
00:12:58
behavior that is basically people being still it's hard in terms of increase
00:13:03
because we we haven't measured time spent sitting for very long that's really been a pretty recent part of
00:13:10
research uh but we do know that today people are sitting for on average N9 to
00:13:16
10 hours per day and that level of sitting um is also linked with really
00:13:21
low levels of then being physically active so um we can think about you know
00:13:27
how many of us are actually active enough to meet the kinds of guidelines that that are prescribed for
00:13:33
health um and we're talking about 25% of us adults actually Meeting those
00:13:38
guidelines and that number hasn't changed in in 20 years or so even with all the messaging physical activity is
00:13:44
good for you you need to be more active you need to exercise you know people just don't do it I guess this the very
00:13:50
heart of this is this idea when we're talking about the brain not just taking care of itself without physical activity
00:13:57
is this notion that all parts of our body and all parts of our being are created in response pretty much or at
00:14:04
least develop in response to an external stimuli of some sort so let me go into the gym the example I gave earlier if I
00:14:09
pick up the weight then the muscle grows and whenever I try and Implement a very sudden behavioral change like when I
00:14:16
suddenly started training football four times a week my my muscles basically exploded in my feet because they just
00:14:23
weren't strong enough to deal with that demand and I guess the same applies to the brain that if we don't use it we we
00:14:30
lose it basically yeah I mean our our bodies are uh fantastic at
00:14:36
tuning what we put energy into to maintain to the kinds of activities that
00:14:41
we're that we're engaged in right and so you know I like to think of our bodies as great energy minimizers in some ways
00:14:48
that you know if you're not using muscles those muscles will get smaller because it takes energy to maintain that
00:14:54
tissue if you're not you know creating the need for your heart to pump blood
00:15:00
across your body by exercising you'll atrophy some of that tissue you'll you'll reduce blood vessels your heart
00:15:05
will become less efficient because you've signaled to your body that you don't need that energy to put be put
00:15:12
into that tissue maintenance the same it seems holds true for the brain that if you're not active um in some way then
00:15:20
you're kind of signaling that you don't need some of that uh energy to be put into that tissue is all activity the
00:15:25
same so if I'm doing strength training is that as beneficial for my brain as potentially going for a run
00:15:32
Outdoors that's a great question and um you know we there is not a ton of very
00:15:39
clear work that's compared directly different types of activity in ways where I could tell you for sure this is
00:15:46
the best one right there are data that suggest that resistance training is beneficial to the brain there's more
00:15:53
work on endurance activity and I actually think that's probably because it's easier to do rodent work on
00:15:58
endurance activity than resistance and so trying to translate across those models is a little bit easier both forms
00:16:04
of exercise have benefits they may be through different Pathways um there may be different biological mechanisms that
00:16:11
are underlying those benefits I've kind of seen some cool work coming out lately that has tried to look at uh for example
00:16:18
different types of endurance exercise so there's a great study that came out are you familiar with orienteering it's a
00:16:24
sport where you're given like a map and a compass and you have to uh find your
00:16:30
way across a route as fast as possible so it kind of mixes endurance activity with spatial navigation and and uh
00:16:38
moving around your environment and figuring out where you are typically done outside right yeah always done outside typically done on natural like
00:16:45
on trails and things but people do do it in cities as well oh okay so like and this is over miles in cles yeah this
00:16:52
would be like a like a trail run kind of or something like that and there was a great study that just came out looking
00:16:57
at um it was a randomized control trial so they actually randomized people into either an orientering group or a hiking
00:17:03
group or a control group and over a couple months they found that the orienteering group actually had uh
00:17:11
better performance on uh cognitive tests like memory tests and executive function tests than even the hiking group both of
00:17:18
those groups did better than the control group but there was actually this extra boost if they if for the people who were in the orienteering group so we're
00:17:25
starting to see that maybe some different activ ities could potentially enhance the effects of exercise on the
00:17:32
brain what's the conclusion there what does that study hint at in terms of
00:17:37
because hiking you're out in nature you're navigating your way up a hill or something orientering that it's it's almost like
00:17:44
solving a puzzle right because you've got a map and a compass yeah I mean I think it it fits into an evolutionary
00:17:50
model at least in my mind um where the purpose of being Physically Active is to
00:17:57
move around a habit to find things find food find water find firewood um and so
00:18:03
physical activity in in this sort of ecologically relevant world is a combination of cognitive challenges and
00:18:11
physical challenges so I think that when you combine them in the way that perhaps
00:18:16
orienteering does or maybe some other sports you might actually get a bigger boost for your buck a bigger bang for
00:18:23
your buck um in terms of the brain benefits and that I think is rooted in our evolutionary history like I said I
00:18:29
think that being active in an evolutionary sense always comes with sort of a cognitive challenge nobody's
00:18:35
ever just going out for a workout there's no reason to if you're not if you don't need to find something you're going to relax and rest because you're
00:18:42
an energy minimizer right don't spend that energy if you don't have to is there any animal studies that show how
00:18:49
um have doing challenging exercise so cognitively challenging exercise so exercise that involves problem solving
00:18:56
improves our neuroplasticity or increases our the amount of brain cells we have across our brain yes yeah there
00:19:02
there have been and a great um impetus for our work was some of the work done in rodent studies um by a a professor
00:19:10
named ger Kerman um and he and his group did some work in in Mouse models where
00:19:16
they combined uh access to running Wheels with a very enriched cage
00:19:22
environment um so they looked at they they did a very careful study where they looked at some mice who were just living
00:19:28
in their cage you know normally a control group they looked at mice that were given access to a running wheel
00:19:34
they looked at mice that were given access to this enriched environment that's cognitively challenging and things to play on and then they looked
00:19:41
at a combined group where they combined the running wheel with the enriched environment and they found this effect
00:19:46
where the combined environment doubled the growth and survival of new neurons
00:19:52
compared to either wheel running alone or cage enrichment alone so you got this really cool ative effect um where you
00:20:00
where you really enhance the effects of either one of those behaviors by combining them if we can pull that
00:20:07
conclusion over to human life if we can if one assumes that the same effect will be seen in humans what does that then
00:20:13
tell us we should be doing if we if our objective is to live long happy healthy
00:20:19
lives with fantastic brains what should we then be doing exercise wise well I think number one is just getting active
00:20:25
right so I think you know to me the number one recommendation is you know to
00:20:31
be physically active and especially for people who aren't that active right now um the best thing they can do is get out
00:20:37
and and start walking um but if we want to enhance the effects of physical activity on the brain and build on this
00:20:43
animal work we're starting to see some good evidence that if you do something similar if you combine physical activity
00:20:49
with cognitive challenges you can boost the effects of physical activity on um
00:20:55
on the brain on on especially cognitive uh performance and so you know most of
00:21:00
the work has been in controlled environments so we've done a study where um we built a uh a game that you can
00:21:07
play while you're on an exercise machine um so you combine exercise with
00:21:12
challenging activities right um and we've shown that you can actually get a bigger benefit for cognition when you do
00:21:19
that than when you just exercise or you just play a game and so we can you know
00:21:24
take that and perhaps translate that into the real world and think about way that you can make your exercise more
00:21:31
cognitively challenging so can you go out and and um challenge yourself spatially take new Roots right
00:21:37
oftentimes especially runners or or Walkers they just do the same route every time or same they have two or
00:21:43
three rootes that they do every time depending on how long they want to go but maybe we should be challenging ourselves a little more right maybe we
00:21:49
should take new routes where you get a little lost and then have to find your way back right I'm someone that runs on
00:21:55
the treadmill but Jack over there he runs Outdoors so you're telling me sort
00:22:00
of Topline that Jack is serving his brain more than I am when I'm just on that same treadmill every day in my
00:22:06
hotel room while I'm out here in New York whereas he's running around Central Park it's possible so I think there's
00:22:12
there's a couple things um you know running on a treadmill may end up being a little more like running on a running
00:22:18
wheel for a mouse without the extra enrichment and yeah running outside May provide some of those better benefits we
00:22:25
also know that running outside actually has a lot more more uh benefits than just maybe cognition but also seems to
00:22:31
boost mood a little bit more than running or exercising in more impoverished environments you know Cog
00:22:39
really yes so there's like there's a research movement called the green exercise movement that is uh focused on
00:22:47
uh the impact of exercising in green spaces versus um more urban environments
00:22:53
or or indoors on exercise equipment and I don't want to scare anybody said exercise is great if if you if running
00:23:00
on a treadmill works for someone's lifestyle it is fantastic exercise right but you know what I mean I could go
00:23:05
outside so the only reason I'm not is because I don't know the difference and
00:23:11
so you know it's for someone like me of course I could have gone outside this morning instead of just um being on the
00:23:16
treadmill but I've I I thought they were the same so you're telling me that there is potentially some upside according to
00:23:22
research and me getting outside and running in both mood and neuroplasticity makes me go okay tomorrow a different
00:23:28
decision absolutely I think that I mean to me that's the really surprising outcome of a lot of This research is
00:23:33
that uh moving outside and especially moving in green spaces so moving in um
00:23:39
Parks or near Parks or uh moving on Trails things like that seems to uh have
00:23:45
bigger benefits especially for mood we don't know yet about the cognitive benefits that's our hypothesis but
00:23:51
certainly uh some of the research out there suggests that for mood and feelings of well-being moving your body
00:23:57
in a green space provides a little bit extra benefit than moving in um in like
00:24:02
I said in city streets or in in indoors one of the things I notice all the time
00:24:07
is if I exercise before I do this podcast my brain just seems to work yeah whereas if I get out of bed and I don't
00:24:14
exercise and then I come and do this podcast it's like the words just don't go from my brain to my mouth properly
00:24:19
yeah I mean that's why I got into this right because I started noticing the same thing and I started noticing how
00:24:26
much better I felt after I exercised and you know and and to this day right I mean my wife knows when I didn't go for
00:24:32
a run in the morning right I'm not that Pleasant of a person to be around the rest of the day what is going on there
00:24:37
do you do you know the sort of physiological reason why it feels like if I exercise in the morning before I
00:24:43
have a two-hour conversation my brain and mouth seem to be connected one of the things that I I think is happening
00:24:49
is that um you've activated uh reward centers in your brain that have
00:24:54
increased your arousal right they you've activated these centers in your brain um that are making you feel good and when
00:25:01
we feel good we feel more confident um we're not as sort of stuck in our heads we're not as we're more present um but I
00:25:09
think that is rooted in the rewarding sensations of exercise right it it makes
00:25:14
us feel better and when you feel better you function better across all aspects of your body of of your life um and
00:25:21
those rewards are molecular rewards that are that are popping up it's there's there's similarities with um with how
00:25:28
people feel when they use certain drugs they're activating similar receptors in your brain as when you're using certain
00:25:33
drugs although to a much lower extent um and it's really it's making you you know sharper and and making you more
00:25:39
confident and making you feel better is there a optimal time of day to exercise I know to your point um about any
00:25:46
exercise is better than no exercise but is there an optimal time to exercise I mean when do you exercise and why well I
00:25:53
exercise first thing in the morning why um because I will feel better all day right and so I mean there's two reasons
00:25:59
I think one if I save exercise for later in the day there's a greater chance that things will come up and I'll you know
00:26:05
I'll I'll find excuses not to but mainly it's because first thing in the morning if I exercise my whole day is better
00:26:12
right and so that's the motivation to get out of bed for me and and get out the door is I literally think about how
00:26:18
I will feel if I don't do it um because sometimes it's cold sometimes you don't it's dark you know this time of year you
00:26:24
don't want to do it but if I think about how feel the rest of the day um that's a
00:26:30
big motivator and people might hear this and they they might be starting from zero right they might not be excising at
00:26:36
all what would you say to those people not to be intimidated by the advice out
00:26:43
there about how much you have to exercise because it's actually surprising how little you need to exercise to gain benefits um so if
00:26:50
you're starting from zero the biggest bang for your buck from a public health
00:26:56
standpoint are people who are starting from almost zero and just starting to exercise a little bit right just getting
00:27:03
out the door and taking a thousand steps right something like that you know those those sorts of uh small amounts going
00:27:11
from zero to two three 4,000 steps per day of exercise that's that's the
00:27:17
biggest public health benefit then you start to see diminishing returns right so if you're if you're already
00:27:22
exercising a lot and you and you want to bump it up a little higher you know the amount of benefit you get is is smaller
00:27:29
than going from very little to to more but I think that's the I mean that's the surprising thing for me is that you know
00:27:36
if you if you are not an exerciser getting four or 5,000 steps per day is
00:27:41
going to give you a big cardiovascular benefit and a big benefit for your brain you've studied some of the tribes around
00:27:47
the world so the hatza tribe right is correct yes what what work have you done with them and when did that research
00:27:54
begin so I started working with uh the hza and 2009 that was my first time out there
00:28:00
and we've been working with them and interested in um what kinds of um Health
00:28:07
impacts you see in a hun in the context of a hunting and Gathering lifestyle and they live in what part of the world so
00:28:13
they live in northern Tanzania why did you want to spend time with them so the hodza uh provide a window into what a
00:28:21
hunting and Gathering lifestyle looks like and so if you work with individuals who are still um pretty much full-time
00:28:28
hunting and Gathering um they give you a view of how much physical activity does it take to be a hunter gatherer for
00:28:34
example and how does that relate to biomarkers of cardiovascular health or how does that relate to their cognition
00:28:42
um how does this lifestyle impact the way that they age and the hodza give us this really important view of what that
00:28:49
lifestyle is like in terms of behavior and activity and and um and aging is
00:28:56
there a op timal amount of exercise that's in line with our sort of evolutionary past we said you know that
00:29:02
we've evolved to be active was is there like an average amount I mean do we see this in the hatza tribes do we have any
00:29:09
clues from history yeah I mean it so we can look at what living hunter gatherers
00:29:15
do and that provides us with kind of a clue as to what that lifestyle um might entail and I like I do like to think
00:29:21
about things in terms of steps per day often because that's an easy metric for people to kind of understand and Trav
00:29:27
for themselves there are more complicated ways to to measure physical activity but steps is a good one step
00:29:32
counts and so um the hodza that as we've measured their step counts are getting a
00:29:38
lot so it's like you know 15 to 20,000 steps per day in that range which is quite a bit of of movement and that's
00:29:45
not to say that that is the optimal amount um but that's what we see in hunting and Gathering Lifestyles the
00:29:51
benefits that we get from a public health standpoint start to occur at much smaller levels right so you know four
00:29:59
five 6,000 steps per day you start to see some real benefits and as I said you start to maybe see diminishing returns
00:30:05
as you get higher and higher levels so what's what what we see in the past or see in living Hunter gathers may be
00:30:12
quite different than what's necessarily you know optimal for our health in terms of you know where are we going to get
00:30:18
the most benefit and and where do we start to Trail off with the hazer is that across all age groups or is that
00:30:25
yeah I mean there is a decline in IAL activity with age that's clear but um
00:30:31
but even older adults we we've measured physical activity in adults in their 70s and even their early 80s and they're
00:30:37
still far exceeding what we do in in in uh in the US or the UK or by factor of a
00:30:44
lot of times the way that we measure physical activity is in terms of um how much time they spend in moderate or
00:30:50
vigorous intensity activity um so these are kind of activities that are that get your heart rate up up to about 50 55%
00:30:58
plus of your of your maximum heart rate and older adults are still engaging in
00:31:03
60 70 80 minutes per day of that kind of activity whereas say in the US you might
00:31:09
see older adults on average engaging in two to four minutes per day of that
00:31:15
level of activity to four yeah so on average right for for older adults so we
00:31:21
just don't see as much physical activity in in the US like I said before only 25%
00:31:28
of adults in the US meet physical activity guidelines and physical activity guidelines here are 150 minutes
00:31:34
per week of moderate to vigorous physical activity so in the US 25% of
00:31:40
adults meet those guidelines in the hodza uh those that we've measured are
00:31:45
meeting weekly physical activity guidelines on average in two days so they're getting 300 minutes of physical
00:31:53
activity in a couple days versus you know adults the US who aren't coming close to that one of the biggest Killers
00:32:00
I think maybe the biggest killer of people in the US and I believe in the UK as well is cardiovascular diseases yeah
00:32:07
that is am I right in thinking that is the single biggest that's the disease you're most likely to die from yes I
00:32:12
believe so when we look at the hadza how are they doing in terms of cardiovascular illness so we don't see a
00:32:18
lot of evidence of uh disease risk so we we have not yet measured cardiovascular
00:32:25
outcomes like we haven't measured mortality for example from cardiovascular disease but we have measured uh biomarkers so things like
00:32:32
cholesterol levels triglyceride levels um blood pressure so looked at whether there's hypertension and we see very
00:32:39
little evidence of cardiovascular disease um in this group others other
00:32:44
researchers have looked at other groups so um there's a long-term study of a group in South America called the
00:32:50
chimane um that have been studied in a lot of detail and there they found almost no evidence of cardiovascular
00:32:57
disease and they've been able to look in a much more detailed way at at outcomes like you know death from cardiovascular
00:33:02
disease and they see almost no evidence of of high levels of cardiovascular disease diabetes very little evidence of
00:33:10
diabetes very little evidence of dementia I mean these diseases that we look at as inevitable parts of Aging
00:33:17
they're just not right they are not inevitable a lot of them are a product of our lifestyle and you know I'm I'm
00:33:24
most familiar with dementia and something like 40% of risk of dementia
00:33:30
is preventable it's due to Lifestyle right we have the ability to
00:33:35
modify our risk in really big Ways by altering the way we live what else has
00:33:41
inspired you or caused you to implement behavioral changes into your life new habits based on your work researching
00:33:48
the hadza tribe is there anything at all that has either changed your mind or modified how you live your life yeah I
00:33:54
mean I think a couple of things um number one um physical activity is is
00:34:00
sort of the Cornerstone of my life that's sort of that is that is um that's been driven by my personal sort of uh
00:34:08
enjoyment of it but also from a research standpoint that's been really motivating to maintain an active lifestyle um
00:34:15
across these years but more recently I've been really interested in sitting um which is you know in some ways um
00:34:22
it's it's not really the opposite of being Physically Active um but it's another behavior that we engage in
00:34:28
actually for much more time per day than than anybody's physically active and um we've done a lot of work on resting
00:34:35
behaviors in the hza and that's been an area that I that I've sort of tried to pull into my life as well is um trying
00:34:41
to understand you know how sitting can impact our lives and then how our
00:34:47
evolutionary biology May uh may be tweaked by by this behavior and so I've
00:34:54
tried to implement some things like trying not to sit too long trying to break up my sitting um finding ways to
00:35:01
to um to not be stuck on in a chair all day um and a lot of that's driven by by
00:35:06
my research what's uh what's the issue with sitting so sitting is um sitting is a beautiful thing right I mean we're
00:35:12
doing it right now it's really comfortable and the reason it's comfortable is because we've basically taken all of the load off of our lower
00:35:19
body so we're we're supporting ourselves in these chairs right you got to move around you mention you know when I give
00:35:26
talks about sitting all of a sudden I start seeing people fidgeting right some people get up and and stand up in the
00:35:31
back um so you know you take the load off of your lower legs and your muscles don't have to work and you know not
00:35:37
surprisingly that super comfortable we're not working hard um but the same time what's happening is the our muscles
00:35:44
not being active means that what we normally do to fuel muscle activity which is you know we break up
00:35:50
triglycerides in our bloodstream and that's you know that's those are broken up into fatty acids that fuel muscle
00:35:56
activity that's not happening and so those those fuels now build up in our in
00:36:02
our blood vessels and that's associated with cardiovascular disease so sitting for long periods of time is associated
00:36:09
with some negative Health outcomes and one of the things that we've learned from working with the hodza is that you
00:36:16
know people rest a lot like the hodza they sit for as rest and sit for as long
00:36:22
as we do which was actually super surprising to us we thought that wouldn't be the case we thought they were going to be active you know all the
00:36:28
time and there would be much less sitting but when we finally actually measured it with accelerometers um they're resting for the same amount of
00:36:34
time that we are but they're not sitting in chairs they're resting in postures that require a little muscle activity so
00:36:41
they're squatting or they're they're kneeling or they're sitting on the ground in ways that you know you have to
00:36:46
kind of keep shifting your body around and it's possible that just that kind of low level of muscle activity um is is
00:36:54
how our bodies are well adapted to rest and what's weird is the invention of chairs and what's weird is the invention
00:37:01
of these objects that completely eliminate the need for our lower bodies to use muscle activity chairs a fairly
00:37:08
new invention when when did chairs come into the picture the first chairs that we know about from the archeological record are about 5,000 years old um but
00:37:16
you know the ubiquitous use of chairs is is probably even more recent than that right chairs are chairs are these weird
00:37:22
objects that they're not only you know ergonomic and and and made for you know
00:37:28
our comfort but they also over history have had implications for economic status and power and you know taking a
00:37:34
seat at the table and a throne in in you know in in terms of political power um
00:37:40
where you sit has always been important from a political and and economic and social standpoint so um chairs have have
00:37:47
sort of Taken on a big part of our lives and if you you know if you walk into someone's house you know generally the
00:37:55
first thing that you're seeing is there seating environment right chairs and couches and um and and places to sit are
00:38:03
part of the way we design our world um we don't think about them that often but
00:38:09
we use them more than almost any other object in our lives it's kind of like we assume they've just always been a thing
00:38:14
it's most of these things in our life we assume that this is just the way it's always been and this is therefore normal and acceptable but it must be pretty
00:38:21
Illuminating to go and see these tribes who they must think we're crazy they must think we're so strange by the
00:38:27
things that we do I mean they do but at the same time you know when we work in
00:38:32
in Hodel land we bring chairs because they're comfortable and you know the the first thing that happens when we're out
00:38:38
there is you know this crazy game of musical chairs that if one of us gets up you know someone comes over and sits in
00:38:43
our chair and why is that because they're super comfortable um and so I I don't think they they necessarily think
00:38:49
we're crazy I think they they they you know they enjoy sitting in the chairs um they just don't have them be careful not
00:38:55
to leave any of them that well that's what you know that's what happens is you know we'll go out for the day and and go you know go um you know foraging with
00:39:03
people and and come back and you know you can't find you want to sit down and you can't find a chair because everyone's sitting in your chair but
00:39:09
that's totally fine they they deserve to rest just as much or more than than anybody else what's the Practical advice
00:39:15
do you think there for for employers for people that work at home for people that sit in chairs often because we people
00:39:22
can't just know we can't just do this podcast squatting right when we could but you know what I'm saying very challenging it' be very very challenging
00:39:29
is there some kind of Middle Ground that is um accessible and realistic for us yeah I think the I think the best thing
00:39:34
people can do is just try not to sit for prolonged periods of time I mean there's no way to eliminate sitting and I don't
00:39:40
think that standing all day is is necessarily the answer I don't think that that's necessarily A a benefit
00:39:47
full-time I think breaking up sitting into smaller periods is probably the best thing we can do um so you know one
00:39:55
of the pieces of advice is is actually that I always tell people is you know just drink more water so you got to get up and pee more um that is that's an
00:40:02
easy way to to kind of force yourself not to sit for two hours at a time but you know having those kinds of reminders
00:40:09
that you should get up move around um there's been this popular notion of take an exercise snack break so you know
00:40:16
every 30 minutes every 45 minutes get up and walk up a staircase or do some push-ups or something just to get your
00:40:22
body moving get your muscles working do some squats um and so that can be you
00:40:28
know really beneficial some people will hear that and go yeah but if just doing just getting up and doing a two-minute
00:40:33
walk how's that going to help in the grand scheme of things there's really good evidence so okay couple things um
00:40:38
from an epidemiological standpoint there's been this really great work coming out on um something that's called
00:40:44
vigorous intermittent physical activity um so this is um activity that's not
00:40:51
purposeful it's short in duration but it's vigorous so going up the stairs or walking really briskly for like a minute
00:40:58
or two that in the long run people that do that often have a lower risk of mortality and a lower risk of
00:41:04
cardiovascular disease regardless of purposeful physical activity right so you can actually get big benefits by
00:41:11
just doing these short bursts of activity walking to get your lunch or at
00:41:16
a vigorous Pace at a vigorous Pace yeah I mean walking to get your lunch is great but you get a little bit more
00:41:22
benefit from doing it at a vigorous pace so you know if you're walking and you can't sing at the same time or you can't
00:41:28
talk at the same time that's that's now you're getting into kind of a vigorous intensity um and there's also been
00:41:35
randomized control trials where people have actually in the lab had people sit for you know eight hours not do anything
00:41:42
and then they've taken those same people on another day and had them sit but break it up into you know 20 minutes
00:41:48
break it up and walk on a treadmill for two minutes something like that and those Studies have shown changes in
00:41:54
cardi metabolic markers so they've shown shown changes in um insulin levels and
00:41:59
changes in um in triglyceride levels and and cardiovascular disease biomarkers
00:42:06
just from breaking up your sitting in into into shorter periods so you really can have a a profound effect I think on
00:42:12
your health um by implementing some of these small changes is there you know a
00:42:19
type of EX we touched on this a little bit earlier on but I'm really trying to make a case to myself that I should be
00:42:25
doing more ER iic exercise then I typically do a little bit of aerobic
00:42:30
exercise um unless I'm training for something in particular and a lot of sort of resistance training is there any
00:42:36
case that I should be doing more aerobic exercise or resistance training if my goal is to improve my brain my memory my
00:42:44
cognition I think I mean I think both are important um from from my
00:42:49
perspective aerobic activity you know we're we're thinking about this from an evolutionary standpoint right we've been
00:42:54
talking about this idea of can we boost the effects of exercise by adding cognitive challenges right and so from
00:43:01
my perspective aerobic activity is probably the place where you can do that um in the easiest way um so by moving
00:43:09
yourself outside in new environments um by adding in some some spatial navigation challenges to a workout you
00:43:16
might be able to do that a little easier than than when you're lifting weights you know this whole brain training industry that emerged I think it emerged
00:43:22
like 10 years ago and there became all of these apps that were kind of like puzzles and stuff and they claimed that
00:43:27
if you use these apps and do this brain training stuff then it will um make your memory better your IQ higher all of
00:43:33
these things is there any Merit to these brain training games there does appear to be some um so there do appear to be
00:43:40
some training games that that do improve aspects of um of cognition you know it's
00:43:48
been a it's been a tough industry because not all of the studies are super high quality um and and some of the
00:43:54
claims can be a little bit further ahead of maybe where the science is so are the effects that big like if you do it you
00:44:01
know every day and you invest all this time are you going to get the biggest effect um but there does appear to be
00:44:07
some benefit you know if I were in a perfect world would I be doing
00:44:13
everything I could um to save off the potential for developing dementia yes and so if there's a little bit of
00:44:19
evidence that that could be helpful I would I would definitely jump in and do it just learning generally yeah learning
00:44:26
so learning education um keeping yourself
00:44:31
cognitively challenged throughout your lifespan is clearly um a way to keep
00:44:38
staving off cognitive decline is there research to support the idea that learning or reading or some kind
00:44:43
education for sure for sure and and you know education is a difficult one because education is wrapped up in a lot
00:44:49
of other things right so education is wrapped up in um your parents and socioeconomic class and so when we study
00:44:56
education from an epidemiological standpoint it's really hard to deal with um the kinds of other variables that
00:45:02
could confound those relationships but certainly lifelong learning seems to be associated with better reserve so one of
00:45:09
the things that we think about in terms of cognitive aging is how much Reserve do you build up over the course of your
00:45:15
lifespan so that as we undergo some atrophy and decline which isn't which is
00:45:20
kind of inevitable um have you built up enough Reserve so that that decline doesn't impact your daily life right you
00:45:27
you have enough of this builtup tissue and built up reserve and built up connections um that even if you undergo
00:45:35
some decline or in in tissue it doesn't impact you reserve being kind of like
00:45:40
Pathways is that Reserve could be Pathways right it could be volume volume so it could be a bigger hippocampus or
00:45:46
it could be the connections between your hippocampus and and other parts of the brain and both of those are are
00:45:52
important and you can build those up across your lifespan with physical activity with um cognitive engagement um
00:46:00
things like that and with avoiding some of the sort of negative health behavior
00:46:05
like smoking or excessive alcohol use does excessive alcohol use and smoking shrink the brain they do they are they
00:46:12
are risk factors in cognitive decline and the development of dementia and Alzheimer's disease how much alcohol we
00:46:18
know that excessive like you know excessive consumption over the sort of one drink per day or two drinks per day
00:46:25
for a man one drink per day for a woman um that level of alcohol consumption is
00:46:31
associated with negative Health outcomes including risk of dementia and Alzheimer's disease is so sleep is the
00:46:38
other one that's a big a big factor in cognitive decline right it is and sleep
00:46:43
I mean a lot of things happen during sleep um that are really important one of the things that happens during sleep
00:46:49
we think is that um it's a time where your brain is clearing these plaques
00:46:55
that can build up that are associated with um neurodegenerative disease and so
00:47:01
if that's the case and there's been some evidence that suggests that that sleep is when some of that clearance is happening then poor Sleep
00:47:08
Quality just doesn't allow that function to occur allows those uh plaques to build up sleep is weird in some ways
00:47:15
because it's not always more is better so uh it follows a U-shaped curve in
00:47:21
terms of risk of developing dementia for example where less sleep
00:47:26
and lots of sleep are both associated with higher risk and there's like a sweet spot right there's a sweet spot of
00:47:33
you know call it seven to nine hours a night something like that um that that's
00:47:38
that is where your lowest risk is going to be so you can over sleep you can Here's the the the the caveat to that is
00:47:47
what's going on with overs sleepers that you're not able to sus out in your analysis so a lot of times people
00:47:54
oversleep because they're depressed and we know depression is linked with these neurodegenerative diseases and so it's
00:48:01
it's possible that it's those it's not the actual sleep itself but it's what's linked with too much sleep like
00:48:07
inactivity they might not be exercising as much as other yeah what are you displacing so another yeah that's a great Point another thing that we can
00:48:14
look at is you know you have 24 hours in a day right and so if you sit for an
00:48:20
extra hour that's going to come at the expense of something else if you sleep for an extra hour yeah or exercise or
00:48:27
light physical activity just housework or something um so you can't the day is
00:48:32
not infinite so anything that you choose to do is displacing something else what
00:48:37
about having friends yeah having a partner you know does that is that going to increase my chances of having a great
00:48:44
cognitive function in a big brain well it depends on how good your relationship is so I mean just having a partner
00:48:51
sometimes you know if it's if it's there are ways that that can be associated with negative outcome comes if if your
00:48:56
relationship is is challenging right um but you know so I I think of healthy
00:49:02
aging as linked to really three main behaviors diet physical activity and
00:49:08
social connections okay social connections are key and so you know
00:49:13
we're hearing now there's a kind of a buzzword the epidemic of loneliness especially coming out of the pandemic
00:49:19
years that is really um it's kind of frightening because people have gotten more used to sort of living alone and
00:49:26
being alone um and those social connections are a key aspect of maintaining a healthy brain when we age
00:49:33
we know that um and how do we know well mainly from epidemiology there's two ways to two ways to analyze these these
00:49:40
these questions there are are randomized control trials and sort of observational trials it's really hard to do randomized
00:49:47
control trials on loneliness and and look at long-term outcome so we look at observational data and people who have
00:49:53
stronger social connections who have um it's not necessarily more but it's it's
00:49:59
higher quality social connections who you know if you ask them if they have people they can confide in they'll say
00:50:05
Yes um those people tend to have better brain outcomes than people who who don't
00:50:10
have those connections and if you think about it again I I don't want to make a a sort of an easy evolutionary argument
00:50:17
where we just say this is how we evolved so this is how we live should live now but I mean if you think about our
00:50:23
evolutionary history for for the most part we lived in a in a time where social connections were imperative to
00:50:30
survival right I mean if you are living in a in a hunting and Gathering lifestyle you know you need those social
00:50:37
connections you can't guarantee that you will find food every day so you need to
00:50:43
have connections with other people who you trust and they trust who you're willing to share with right and so those
00:50:49
social connections become um become inextricably linked to your health does
00:50:54
pollution have an impact on our cognitive performance yeah that's been so that's been a surprising and really
00:51:00
kind of sad result of a lot of research lately is that air pollution um has real
00:51:07
negative impacts on brain aging um and we've seen that in acute studies where
00:51:13
people have looked at um the effects of you know what's going on in your in your
00:51:18
peripheral blood when you commute in traffic right when you ride your bike in traffic um but also from an
00:51:24
epidemiological standpoint people who are living in areas with higher air pollution have a higher risk of
00:51:30
developing Alzheimer's disease and other dementias um one of the things that we've done some work on we were really
00:51:36
interested in whether physical activity either could you know diminish those
00:51:41
impacts of air pollution on the brain but also we were thinking well when you're active you're breathing more
00:51:47
right you're your your your respiration increases so you're breathing in more uh pollution more particles so could that
00:51:53
actually you know have an impact on the benefits of activity on your brain and we found we we've looked at a look at
00:52:00
this in a couple ways and both for some brain structural outcomes and for risk of dementia exercising in or being
00:52:06
physically active in in an area with even moderate levels of air pollution diminishes the benefits of physical
00:52:13
activity on the brain which is a real bummer especially for me I live in Los Angeles which is a very uh it's an area
00:52:20
with a lot of air pollution and um and so being physically active in that environment when there's a lot of
00:52:26
pollution in the air um it doesn't it doesn't make your health outcome worse
00:52:32
but it diminishes the benefits of physical activity so if you go for a a run in the middle of London for example
00:52:37
or in the middle of New York City the cognitive benefits are diminished that's what we're seeing in the data we're
00:52:43
seeing and in fact the study that we did was was uh from data uh based in the UK
00:52:48
where you know we're not seeing the kinds of levels of pollution that we see in some other cities around the world where it's really drastic or even in Los
00:52:56
Angeles where it's much higher levels of pollution than we'd see in say London but even in those levels with more
00:53:01
moderate levels of air pollution um people who are active in in higher levels of air pollution don't show the
00:53:08
same brain benefits as people who are active in areas with lower pollution I
00:53:13
had my brain scanned uh what two months ago now and it was okay okay it wasn't
00:53:21
amazing it what do you mean by okay I mean he just told me there was room for improvement in terms of like some things
00:53:26
he saw in my brain he also diagnosed me with ADHD following that and a few other questionnaires and and things one of the
00:53:31
things in my sort of prescription that he asked me to do more of was racket Sports interesting okay he
00:53:39
said if you do this list of things that he's asked me to do things like hyperbaric chambers and blah blah blah
00:53:44
blah blah blah and Racket Sports um we'll see an increase in certain parts
00:53:50
of your brain now that somewhat ties into what you're saying with doing this
00:53:55
physical activity but pairing it with some kind of cognitive challenge racket Sports seems like a prime example it's
00:54:02
actually it's funny it it is the number one question I get after I give a talk is about tennis and I think I probably
00:54:08
you know I give talks a lot in in you know to communities with you know more a sometimes more affluent older adults who
00:54:15
probably play a lot of tennis and but it is you know it's an activity that people play can play later in life you know um
00:54:22
and um and it does involve a lot of strategic thinking it involves a lot of
00:54:27
fast reactions and it involves aerobic activity um and so it is it's a great Contender and you're doing and you're
00:54:33
doing with someone it's social um oftentimes especially U when you get a little older you play doubles um so you
00:54:39
don't have to run the court as much what are the other questions people after hearing you speak what are the other questions that people often are most
00:54:46
curious about how much activity that's the big one right how much do I have to do do I have to do right that's way
00:54:53
people think about it yeah and you know I think have to do yeah and it it it's
00:54:59
it sort of does bum me out to frame it that way because um because I think of physical activity as as something that
00:55:06
as as we were just talking about it improves your whole day um it's something that many of us want to do
00:55:12
because of that right and so I think you know first the first thing I always tell people is find the activity you want to
00:55:19
do because that's the one you'll keep doing and so don't look for the perfect right if running a treadmill makes you
00:55:26
crazy and you don't want to do it then you won't keep it up um if playing tennis does it for you maybe it's not
00:55:32
the best if we fig you know if we can even figure out what that means but you're going to do it for the rest of
00:55:37
your life then by all means that's the one to do and so I think that is the first thing that everyone should be
00:55:43
thinking about is you know what do you what do you what makes you excited to get out the door and do um and don't
00:55:50
worry about what's best what is the research that you've done that you're most proud of or that surpris surprised
00:55:56
you the most because you know I've I've been looking through your work and found different things that I found
00:56:02
interesting but um I must have missed something that you find really fascinating well one of the things that
00:56:08
I found really surprising was actually it was it's now been a while it's been like over over a decade ago I did some
00:56:15
work on um the endoc canabo system um and the endoc canabo system is our
00:56:20
body's uh sort of natural form of marijuana you know we produce these uh
00:56:26
chemicals that activate brain receptors the same way that the active ingredient in marijuana um activates and so um it
00:56:33
turns out that exercise upregulates the same system um these endoc canabo and that may be why at least partially why
00:56:39
exercise makes people feel good um and one of the studies that we did like I said about 10 11 years ago now uh was we
00:56:46
found that the same thing that we get from exercise in terms of endoc canabo signaling dogs also get that and I'm I'm
00:56:54
a dog dog lover and I know my dog loves to exercise and she's you know bummed
00:56:59
out if she can't get her her her walk and run in for the day and I think there's something similar going on it's
00:57:05
these similar rewarding mechanisms that make them feel good that that makes us feel good so that was one um one really
00:57:12
fun and and interesting kind of finding that I think has some implications right it's it's if if if we can find those
00:57:19
activities that generate those rewards we're going to want to do that more often and it also provides a sort of
00:57:25
physiological explanation as to why some people who don't exercise or aren't able
00:57:31
to exercise can often have depressive symptoms agree I totally agree yeah and I think these biological mechanisms that
00:57:38
can that can make you feel better when you exercise they don't always kick in right away right and so I also think
00:57:45
they can be a that can be a little bit of a barrier to someone who's not active that you know if you just get up and
00:57:50
start exercising you know maybe it takes a little bit of time for these things to kick in you have to be able to stay
00:57:56
within a certain intensity level and maybe if you're not very fit you kind of overshoot that and you you end up going
00:58:01
too too intense and you don't get those same sort of mild benefits that just
00:58:07
make you feel good all day right I think one of the things that people need to kind of keep in mind is is maybe try to
00:58:12
stick with it long enough to get a little bit of Fitness so you can reap those rewards they'll come you just need
00:58:18
to just give it some time right have you got any hypothesis that you're working on at the moment that you have haven't
00:58:25
been able to prove out yet but you know as someone that's a researcher and that's insanely curious there must be things in your mind that you're thinking
00:58:30
I'd love to do a study on that to figure out if that's true yeah I mean so a
00:58:36
couple things I mean one we are not done with the combining cognitive challenges with physical activity I think that is a
00:58:42
really um a really exciting area and it's it's early on so I think the the
00:58:49
work that we've done and others have done is in its infancy and how we can boost the the the brain benefits of
00:58:55
exercise and that's sort of that's going to be a big part of our work going forward is what can we do to really um
00:59:02
make exercise a little more cognitively challenging and get those benefits um the area that I'm that I'm really
00:59:07
interested in now um is the effects of sitting on the brain and um what are the
00:59:15
mechanisms that link too much time spent sitting with brain health and how can we
00:59:20
kind of manage that a little bit better you know when we think about exercise participation and I've been
00:59:27
saying you know 25% of adults engage in in uh the guidelines for physical
00:59:33
activity levels in the US that number hasn't changed over the last you know couple decades all the messaging I mean
00:59:39
you know would you could you ever meet someone who doesn't know that physical activity is important to do but still
00:59:44
75% of people don't exercise and so I don't know what it'll take to to change
00:59:49
that number but I think maybe we can look at other behaviors that we can change and sitting is something that
00:59:56
everyone does and so that I think is a really nice place to focus to move the needle a little bit so can we get people
01:00:03
to sit less what are the kinds of interventions we can Implement that can get people to to reduce their time spent
01:00:09
sitting and will that pay off in terms of brain health and I think that's it's a big question we know that time spent
01:00:16
sitting is associated with risk of dementia we just we just did a big study looking at you know if you if you sit
01:00:22
for 10 hours a day compared to nine hours a day it's about
01:00:28
a 10% increased risk of dementia if you sit for 12 hours a day it's about a 60%
01:00:33
increase risk of dementia compared to sitting for N9 n and a half% 60% versus 9 hours a day right so just a couple
01:00:40
more hours right it's it's a nonlinear relationship so once you get past about
01:00:46
nine nine and a half hours a day your risks start going up in in a nonlinear exponential way and so can we alter that
01:00:54
can can we I mean it doesn't it doesn't take a lot necessarily to go from 12 to 8 hours a day so maybe that's easier
01:01:02
than getting people out the door maybe we can find some find some intervention so that's what I'm really excited about
01:01:07
is you know some of some lowcost ideas some low investment ideas for people um
01:01:15
that could maybe have a big impact on the way they age I'm thinking about all kinds of chairs that vibrate and give
01:01:21
you an electric shock I'm thinking of how we can Implement that into which is aany involved in totally yeah I
01:01:28
mean reminders are one way right I mean I think tracking um your behavior I mean there it's not going to work for
01:01:33
everybody but certainly tracking your time spent sitting for a couple weeks might actually give you a little bit of
01:01:39
motivation once you realize just how much time you spend on these chairs what is brain foods is is there
01:01:46
such thing as a brain food I think I much the reason I take aega is because people tell me it's good for your brain yeah I don't you know I don't think
01:01:52
there's a magic pill um I you know I think the best evidence that we have
01:01:58
right now is um is more plant-based less meat-based especially less processed
01:02:04
meat more plant-based more plant-based foods and and Less meat Less meat yeah
01:02:09
here's where the difficulty lies in all of this research to study brain health
01:02:15
you need to observe people over long periods of time and so you can't Implement a a 10-year diet intervention
01:02:22
just nobody will follow it so all of the research that's really um strong in this area is asking people to report what
01:02:29
they eat and then tracking what happens to them over time so it's it's difficult
01:02:34
work but the best evidence is that aspects of the Mediterranean diet seem
01:02:39
to be linked with better brain outcomes so more plant-based more um more legumes
01:02:47
more whole grains less processed food Less meat less sugar these are you know
01:02:54
these are the obvious dietary interventions right and I think they're they're obvious for a reason because
01:02:59
they seem to be so good for so much of our bodies and you know so much of our cardiovascular metabolic health and our
01:03:06
brain health if there was one fundamental misunderstanding that most people have that your work and your
01:03:14
experience has um rebutted I guess what is that fundamental human
01:03:19
misunderstanding about the nature of our bodies and how we're supposed to be living to be optimal I think I think the
01:03:26
most dangerous misunderstanding is how much exercise it takes to get benefits right and I think that's because that
01:03:33
acts as a barrier to people and what we've seen from the epidemiological work is that you know the the there are
01:03:41
minimal amounts of activity that provide big benefits more is generally better
01:03:47
but you can get huge benefits just by moving your body a little bit every day and so I think that's you know as I said
01:03:54
it's a dangerous misconception because it's a barrier when someone thinks when someone doesn't exercise at all and
01:03:59
thinks I need to get 12,000 steps per day and I'm tracking it and I'm getting 3,000 that's a pretty big gap and that's
01:04:06
one that maybe you don't think you can fill but if you're getting 3,000 and you think if I get to 5,000 I'm gonna get a
01:04:13
big benefit that's motivating right it's so true that sometimes going from zero
01:04:20
to one feels so hm inconsequential and somewhat
01:04:26
embarrassing that we just don't do it because we I think many people think of 0 to one as like zero to a five day a
01:04:34
week gym attendance record right which is just like climbing Mount Everest in your mind it's just so far away that
01:04:40
there's going to be so much psychological discomfort it's going to result in procrastination you're going to do something else and you're going to avoid it but if we reframe that to zero
01:04:48
to one being walking for your lunch yeah and that as the starting point and then one to two being as you said going from
01:04:54
1,000 steps to maybe 2,000 steps feels like something everyone can do but we just don't think it's important we think it's totally inconsequential to go for a
01:05:01
walk as opposed to um you know just sitting down and ordering our food on an
01:05:06
app yeah something that I I think about a lot because even as someone like me that I I go to the gym you know um as
01:05:13
frequently as I possibly can however there are some days like today where I'm
01:05:18
extremely busy where I might have said I was going to go to the gym lateer at night and I either think to my myself
01:05:25
that there's no middle ground I think that's either going to the gym and working really hard or [ __ ] it yeah yeah
01:05:31
there's great middle ground though yeah you can run up the stairs on your way to bed right you know I mean you really or you you know you can do these exercise
01:05:38
snacks but I like to think of the the things that you're talking about you know walk to lunch instead of ordering
01:05:44
in you think that's not important maybe it's life-changing for some people it
01:05:50
will literally change your life if if you are doing very little and you take that first step you know it can change
01:05:58
everything about your you know your future in some ways um because it builds the foundation for oh that feels good
01:06:05
maybe I'll try a little bit more right maybe I'll try a little bit more you know we were talking earlier you were saying you know you implement a new
01:06:11
exercise regimen and you jump in with everything and then you end up you know getting a achilles tendon injury or
01:06:17
something like that you know that's especially true of people who don't exercise at all and so you know the best
01:06:23
thing to do is to start slowly and really start reaping those rewards because that's the motivator and so yeah
01:06:28
I mean I think if you are exercising a lot you know day that gets away from you and you can't make it to the gym I mean
01:06:35
getting a little bit of vigorous activity going for a really brisk walk going up the stairs doing some pushup I
01:06:41
mean anything is going to give you a little bit of benefit um you know these are really easy things that we can
01:06:47
Implement into our lives quick one from one of our sponsors a lot of you have asked me the question about Hu over the
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01:07:13
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01:07:51
exist on a spectrum per se and is is what one end of that Spectrum sort of
01:07:56
just general cognitive decline and memory reduction because I sometimes wonder obviously my job here is to I
01:08:02
interview very intelligent people and those people come in all shapes sizes and ages and I obviously as an observer
01:08:10
notice how some of the older people that I meet are
01:08:16
incredibly sharp you know arguably significantly sharper than I am and I'm you know in
01:08:23
some cas is 30% 40% of their age 40% of their age um and they're just
01:08:29
unbelievably sharp and then we've also all had experiences maybe with an elder relative or you know someone slightly
01:08:34
older where you can see that that their memory recall or their sort of it's
01:08:39
almost sometimes you experience it as their self-awareness has started to wne they might tell you a short story in one
01:08:47
hour if you know what I'm saying they might they just it's almost like the self-awareness of what they're saying and how they're saying it and their
01:08:53
ability articulate themselves has some somewhat slipped away and I wonder if that exists on this scale of Dementia or
01:08:59
whether that's just general atrophy as you call it of the brain right and I don't I really really want to be someone
01:09:05
as I'm sure we all do that has my brain works until the day that I die yeah you
01:09:11
know yeah we all want that yeah we all want that and of course and I that's why I wonder if it's the Spectrum or is it
01:09:16
is a spectrum yeah I mean so there's sort of a a a a normal amount of of cognitive change that happens with aging
01:09:23
in most people um that in general should not impact your daily life greatly right
01:09:29
you should still be able to do all the things you want to do navigate your world in the way that you want to you
01:09:34
may have some you know it's inevitable that there will be some memory changes um some changes in your in your
01:09:41
executive functions planning but not the kinds of profound changes that we see in
01:09:46
people with dementia and so dementia is is is cognitive decline that impacts your daily life in in a way that makes
01:09:53
it hard hard to keep doing the things you want to do um when you start to get down into sort of the nitty-gritty of
01:10:00
different types of dementia you know Alzheimer's disease which is by far the most common has a lot of pathological
01:10:06
features that make it a progressive disease right that that mean you know you will continue to decline um over
01:10:13
over the course of the disease and there's no way to stop it really that we know of but there is going to be there's always going to be some change in your
01:10:19
brain with age that you can't fully stop for most people I've also always wondered about this is totally random
01:10:25
but I said this a few times to a few people this idea that when a spouse or a partner passes away people seem to go
01:10:33
into pretty quick cognitive decline and their sort of mortality risk seems to multiply and that could be a very
01:10:39
complex thing to do with cortisol and other things going on in the body and hormones and but I wondered if there was
01:10:44
accelerated atrophy if my if I'm 85 and my wife passes away yeah so I mean a couple things are going on Grief in
01:10:52
itself is associated with brain changes um there's been interesting work on that brain changes yeah I mean that there are
01:10:58
cognitive changes and and structural changes that happen when you're grieving I think some of this is depression as
01:11:04
well that's clear and one of the things you know untreated depression can start
01:11:09
to look a lot like dementia it's a risk factor for dementia but it can also look like dementia because when you are
01:11:15
undergoing um depression a lot of things happen you stop paying attention when you're talking to people you're you're
01:11:22
you're you're not as present and so you know what can sometimes seem like a
01:11:27
memory deficit might be because you weren't pay able to pay attention to what was going on in the first place and
01:11:32
so I think one of the things that I worry about with older adults a lot is making sure that depression is treated
01:11:39
because especially when there are cognitive challenges that they're that they're experiencing they're they're
01:11:45
feeling like they're have declines in their thinking and memory skills making
01:11:50
sure they're not depressed is the first step because you can treat that and actually you can treat that really well with exercise so you might be able to
01:11:56
get a couple of bangs for your buck by both treating your you know helping to manage your depressive symptoms and
01:12:02
getting the brain other brain benefits but you can also treat it pharmaceutically or with therapy and
01:12:08
that can have a profound impact on the way that you think and the way that you manage um those symptoms so yeah I think
01:12:15
losing a partner you're also losing a social connection and we know that social connections are so important and
01:12:21
so that loneliness and that loss of a social connection is important so um I think that's that's all wrapped up in
01:12:27
these brain changes and these are all modifiable things we can watch out for our parents or people in our community
01:12:33
when these are H things are happening and try to help them maintain better social connections we have a closing tradition
01:12:40
on this podcast where the last guest leaves a question for the next guest unaware of who they'll be leaving it for and the question left for you
01:12:46
interesting maybe a little bit obvious but how can your work help the world
01:12:53
it's a simple answer I guess but I think it's profound that if you if you sit
01:12:58
less and you move more you will not only help yourself but you will also help the
01:13:04
general population right I mean we when when we talk about um uh aging it
01:13:11
doesn't just affect you right it affects everybody around you it affects your
01:13:16
family caregivers it affects our economy I mean the US is is is is we're thinking
01:13:24
the US might end up spending a trillion dollars a year on Alzheimer's Disease by 2050 right and so prevention will have a
01:13:32
big impact on our economy and I'm not saying people should Implement sitting less and moving more for our economy but
01:13:38
by doing that you might actually on a broad scale have a big impact on on our world and so you know I hope that that
01:13:46
message gets out there that's why I'm so I was excited to you know to do this podcast with you because you know I
01:13:52
think it is a message that we need to keep repeating and and and find ways to help people do that because I think it
01:13:57
can have a profound effect on themselves their family and Society are you hopeful
01:14:04
well that's a hard question to answer I mean I I am on some level because I
01:14:09
think you know especially with the focus on you know start moving away from
01:14:14
having people do big steps and trying to get people to do small steps first I am hopeful that we can motivate people to
01:14:20
to implement these these changes I I hope it possible um it's been hard to do
01:14:26
is the the data going in the wrong direction at the moment generally you know what we just haven't seen big
01:14:31
improvements in in adherence and I think one of the things I'm worried about is that
01:14:37
worldwide uh more countries are becoming more like the US and UK and instead of
01:14:42
less right and our societies are aging and so you know we have a larger number
01:14:48
of older people and so just by the sheer numbers we're going to have more people with these these diseases and so you
01:14:56
know implementing these these um increases in activity reductions and
01:15:01
sedentary Behavior hopefully will have these kind of profound effects on our aging Society but I think it needs to be
01:15:08
our Focus like right now you know when we think about Alzheimer's disease we don't have drugs that that are going to
01:15:13
have a big impact I mean there's some new drugs that that are promising maybe um but the biggest thing we can do is
01:15:19
prevention and that's where this work comes in is you know if we can prevent or delay we can save people happiness I
01:15:28
mean improve their happiness and we can save money and we can improve Society David thank you thank you absolutely
01:15:34
incredibly enlightening and inspiring and maybe most importantly of all motivating conversation motivating
01:15:40
because knowledge is power um and you've given me so much knowledge which has added fuel to a bunch of different
01:15:48
behaviors that are critical for my cognitive outcomes but also just My overall all day-to-day health so thank
01:15:54
you so much for that thank you so much for doing the work that you do because I know you're probably doing it in part
01:16:00
because you're incredibly curious and you love it um but the other part of that is it's an incredible service to
01:16:05
all of us that you go out there and you take this time to do all this research that you then pass out to society in a
01:16:11
way that's going to serve us and get us close to the goals that matter most keep us healthy and happy into our later years and keep families together
01:16:19
ultimately so thank you for the work you do and thank you for being here today you're welcome thanks so much for having me on it's
01:16:24
pleasure quick one as you might know a company that I've invested in is now also a sponsor of this podcast and
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[Music] it
