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the first thing we need to do is
understand the difference between
physical activity and exercise so
physical activity is just moving if you
sweep the floor make dinner that's all
physical activity but exercise is a kind
of physical activity that's intentional
it's discretionary undertaken for the
sake of health and fitness and that's
actually a very modern strange behavior
nobody ever used to do that you can
spend your entire day sitting in chairs
and pushing buttons and never have to
break a sweat in order to survive but
our ancestors of course had to be
physically active to survive but they
also struggled to get enough calories to
get through the day so they were careful
not to do physical activity when it
wasn't either necessary or rewarding
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common sense tells us that our bodies
were programmed to be as active as our
hunter-gatherer ancestors were but from
an evolutionary perspective we're
actually hard-wired not to waste
precious energy in vain
our ancestors were physically active in
order to get food or avoid being
somebody else's food but other than that
they sensibly conserved energy and so if
you go into a camp of hunter-gatherers
most of the time people are sitting
right and we demonize sitting and say
look you know you know sitting is then
you're smoking and your chair is out to
kill you and but there's nothing strange
about sitting it's just that if that's
all you do then you run into trouble
only about 20 of americans get the
minimum level of exercise you know
recommended by the government which is
150 minutes a week of moderate to
vigorous physical activity and the fact
that they struggle to exercise
isn't some personal failings people are
simply doing what what we evolve to do
which is to avoid physical activity when
it's neither necessary nor rewarding
another problem is that most people
exercise just because they hope to lose
weight but the truth is our bodies have
not evolved to burn more calories the
more physically active we are
we went to work with a hodzia community
in northern tanzania one of the few
traditional hunting and gathering
communities left in the world and the
hadza they don't have any domesticated
animals or plants or machines or guns or
electricity or plumbing or anything like
that and every morning men go and hunt
wild animals with bows and arrows women
go out every day and they dig for wild
tubers root vegetables with a digging
stick they get more physical activity
walking and chopping and digging more
activity in a day
than most americans get in a week and we
were sure that we would find they would
burn more energy every day than
americans in fact dr ponza found quite
the opposite
the hot men and women out there getting
more activity every day than you get in
a week had the same energy expenditure
per day as sedentary americans and
europeans huge surprise researchers were
so surprised that they doubted the
results so they went out to collect more
data in different hunter-gatherer
communities using different techniques
we see the same thing again and again
people who are more physically active
don't burn more calories necessarily
than people who are more sedentary we
see this in other animals we see this in
mice in a laboratory monkeys in the zoo
have the same daily energy expenditure
as monkeys in the wild our bodies are
evolved to keep energy expenditure
within a kind of narrow range that we
can afford right that we can meet those
demands every day so if you spend a lot
of energy on exercise your body will
probably respond by spending less energy
on other things but this is no excuse to
be sedentary please please understand
this is not an excuse to not exercise
right you don't it's not a free pass we
often talk about diet and exercise as
two sides of the same coin right if i
don't want to exercise today i'll just
watch my diet or if i don't want to diet
i'll just exercise more like you can
trade them back and forth and these
results from my work and other people's
work
say no no no it doesn't work that way
diet and exercise are two separate tools
with two separate jobs you need to diet
to watch your weight you need to
exercise for everything else exercise
has such a big impact on not just your
muscles and your heart it affects every
part of your body because it's affecting
how those other systems spend their
energy and how active they are and so we
know that for example if people exercise
more things like inflammation are
reduced but if exercising for the sake
of fitness is an unnatural behavior how
can we inspire people to be more active
i think we should treat exercise the way
we treat education so education is also
a very modern behavior we never evolved
to it to do think about it until a few
100 years ago almost nobody on the
planet was literate now you know
literacy and education are considered
universal
dr lieberman proposes to make exercise
not only necessary but also fun and
social i have friends who i run with
right and i we often agree you know the
night before that we're going to meet at
like 6 a.m and then all of a sudden now
at 6 a.m you know i don't want to be
there but i've already made an agreement
to meet my friends and i can't let them
down right and and then when i meet them
they kind of make me you know glad that
i went after all you don't have to run a
marathon or or swim the english channel
or climb mount everest just climbing the
stairs in your building or walking to
work instead of you know driving or
walking your dog or all of those things
have enormous enormous benefits
the benefits are even greater as we get
older the hunter-gatherers who survived
childhood typically live about seven
decades they become grandparents and
when they become grandparents they don't
retire and you know move to the south of
france or florida or wherever they
actually stay very active and that
activity helps turn on all kinds of
repair and maintenance mechanisms in the
body that keep us healthy and so we
evolved not only to live long but also
to be physically active
as we age and that physical activity
actually helps us age better
recent studies are providing new insight
into how our bodies work it was found
for example that our metabolism slows
down much later than previously thought
your metabolism is really stable from
about 20 years old to 60. that was
surprising because there's this
conventional idea this conventional
wisdom that your metabolism slows down
in middle aged but we don't see any data
for that at all but it's still up to us
to choose to live long healthy lives we
have to choose now for example not to
eat foods that are highly processed and
full of sugar and fat that are really
tasty and delicious right we now have to
choose to be physically active when we
otherwise wouldn't have to do that
that's difficult right especially when
it's also a matter of opportunity
the exercise has become a privilege of
people with wealth and means it used to
be that only rich people could be
physically inactive now it's the other
way around it's only rich people who can
actually afford you know gym memberships
and and living in places where there are
you know access to facilities to
exercise we need to as a society to make
these resources available to absolutely
everybody
you