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we never evolved to exercise.
no one ever ran or walked several miles just for health.
punish prisoners and prevent idleness.
many of our beliefs and attitudes about exercise are myths (by
that by ignoring or misinterpreting evolutionary and anthropological perspectives on physical activity, the contemporary, industrial approach to exercise is marred by misconceptions, overstatements, faulty logic, occasional mistruths, and inexcusable finger-pointing.
Exhorting us to “Just Do It” is about as helpful as telling a drug addict to “Just Say No.”
understand the paradox of exercise—that is, why and how something we never evolved to do is so healthy.
The mantra of this book is that nothing about the biology of exercise makes sense except in the light of evolution, and nothing about exercise as a behavior makes sense except in the light of anthropology.6
“Why,” he asked me with evident disbelief, “would anyone run when they didn’t have to?”
the average adult Hadza spends a grand total of three hours and forty minutes a day doing light activities and two hours and fourteen minutes a day doing moderate or vigorous activities.
On average, the women walk five miles a day and dig for several hours, whereas the men walk between seven and ten miles a day.
comprehensive studies of contemporary foraging populations from Africa, Asia, and the Americas indicate that a typical human workday used to be about seven hours, with much of that time spent on light
activities and at most an hour of vigorous activity.
In other words, typical hunter-gatherers are about as physically active as Americans or Europeans who include about an hour of exercise in their daily routine.
you are a typical person who barely exercises, it would take you just an hour or two of walking per day to be as physically active as a hunter-gatherer.
how we define exercise and play.
define “exercise” as a “planned, structured physical activity to improve health, fitness, or physical skills,”
“play” as “an activity undertaken for no serious practical purpose.”
exercise outside the context of sports was extremely rare until relatively recently.
recent technological and social developments have diminished industrialized people’s need to be physically active, a growing chorus of experts has never ceased to raise the alarm that we aren’t exercising enough.
Philosophers like Plato, Socrates, and Zeno of Citium preached that to live the best possible life, one should exercise not only one’s mind but also one’s body.
Chinese philosophers also taught that exercise was equally essential for physical and mental health and encouraged regular gymnastics and martial arts.
Unsurprisingly, exercise has become increasingly advertised as virtuous and has been commodified, commercialized, and industrialized.
apes make them seem like workaholics. And
that human resting metabolisms are flexible.
Their heart rates decreased by one-third, and their body temperatures dropped from a normal 98.6°F to 95.8°F, causing them to feel constantly cold,
Your brain and liver each consume about 20 percent of your resting metabolism,
your muscles expend 16 to 22 percent of your resting metabolism.
you are sitting while reading this, for every five breaths you take, one pays for your brain, another for your liver, a third for your muscles, and the last two pay for the rest of your body.
resting is not just a state of physical inactivity.
As you read these words, you are spending roughly sixty calories an hour (the energy in a typical orange) tending to your brain, liver, muscles, kidneys, intestines,
We use energy as we do in large part because of the way Darwinian evolution acted on millions of generations of our ancestors.
one of the most fundamental is whether to spend precious calories being physically inactive or active.
given calorie in just five ways: growing your body, maintaining your body (resting metabolism), storing energy (as fat), being active, or reproducing.
Like an unsentimental novelist such as Jane Austen, natural selection doesn’t care if we are happy, nice, or wealthy; it just favors heritable traits, including trade-offs, that enable us to have more children.
Stated simply, we evolved to be as inactive as possible. Or to be more precise, our bodies were selected to spend enough but not too much energy on nonreproductive functions including physical activity.
No sensible adult hunter-gatherer wastes five hundred calories running five miles just for kicks.
So if, as you read these words, you are seated in a chair or lounging in bed and feeling guilty about your indolence, take solace in knowing that your current state of physical inactivity is an ancient, fundamental strategy to allocate scarce energy
In fact, compared with other mammals, humans might have evolved to be especially averse to exercise.
People who avoid exercise are commonly labeled lazy, but aren’t these exercise avoiders behaving normally?
The more calories we need, the more we are vulnerable to not having enough.
Of the 151 people I observed during those ten minutes, only 11 took the stairs, about 7 percent. Apparently, people who study and promote exercise are no different from the rest of us. Worldwide, the average is just 5 percent.
we need to override ancient, powerful instincts to avoid unnecessary physical activity, and it should hardly be surprising that most of us—hunter-gatherers included—naturally avoid exercise.
So let’s banish the myth that resting, relaxing, taking it easy, or whatever you want to call inactivity is an unnatural, indolent absence of physical activity.
The problem, however, is that until recently only great kings and queens could enjoy taking it easy whenever they wanted.
voluntary physical activity for the sake of health—a.k.a. exercise—has become a privilege for the privileged.
find that average adult Americans are sedentary 55 to 75 percent of the time they are awake.
between nine and thirteen hours a day.
older individuals average slightly more than twelve hours a day.
total time Americans spent sitting increased 43 percent between 1965 and 2009,
