Dopamine Nation

Scientist in 1969 in which she described the experiences of people struck by
lightning who lived to tell about it. “My neighbor’s son was struck by
lightning as he was returning from a golf course. He was thrown to the
ground. His shorts were torn to shreds and he was burned across his thighs.
When his companion sat him up, he screamed ‘I’m dead, I’m dead.’ His legs
were numb and blue and he could not move. By the time he reached the
nearest hospital he was euphoric. His pulse was very slow.” This account
recalls the dog’s “fit of joy,” including the slowed pulse.
We’ve all experienced some version of pain giving way to pleasure.
Perhaps like Socrates, you’ve noticed an improved mood after a period of
being ill, or felt a runner’s high after exercise, or took inexplicable pleasure
in a scary movie. Just as pain is the price we pay for pleasure, so too is
pleasure our reward for pain.

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The Science of Hormesis
Hormesis is a branch of science that studies the beneficial effects of
administering small to moderate doses of noxious and/or painful stimuli, such
as cold, heat, gravitational changes, radiation, food restriction, and exercise.
Hormesis comes from the ancient Greek hormáein: to set in motion, impel,
urge on.
Edward J. Calabrese, an American toxicologist and a leader in the field of
hormesis, describes this phenomenon as the “adaptive responses of
biological systems to moderate environmental or self-imposed challenges
through which the system improves its functionality and/or tolerance to more
severe challenges.”
Worms exposed to temperatures above their preferred 20 degrees Celsius
(35 degrees C for two hours) lived 25 percent longer and were 25 percent
more likely to survive subsequent high temperatures than nonexposed worms.
But too much heat wasn’t good. Four hours as opposed to two hours of heat
exposure reduced subsequent heat tolerance and reduced lifespan by a fourth.
Fruit flies that were spun in a centrifuge for two to four weeks not only
outlived unspun flies but were also more agile in their older age, able to
climb higher and longer than their nonexposed counterparts. But flies spun
longer than that did not thrive.
Among Japanese citizens living outside the epicenter of the 1945 nuclear
attack, those with low-dose radiation exposure may have shown marginally
longer lifespans and decreased rates of cancer compared to un-irradiated
individuals. Of those living in the direct vicinity of the atomic blast,
approximately 200,000 died instantaneously.
The authors theorized that “low-dose stimulation of DNA damage repair,
the removal of aberrant cells via stimulated apoptosis [cell death], and
elimination of cancer cells via stimulated anticancer immunity” are at the
heart of the beneficial effects of radiation hormesis.
Note that these findings are controversial, and a follow-up paper published
in the prestigious Lancet disputed them.

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Intermittent fasting and calorie restriction extended lifespan and increased
resistance to age-related diseases in rodents and monkeys, as well as
reduced blood pressure and increased heart rate variability.
Intermittent fasting has become somewhat popular as a way to lose weight
and improve well-being. Fasting algorithms include alternate-day fasting,
one-day-per-week fasting, up-to-the-ninth-hour fasting, one-meal-per-day
fasting, 16:8 fasting (fasting for sixteen hours each day and doing all your
eating within the other eight-hour window), and so on.
American celebrity talk show host Jimmy Kimmel practices intermittent
fasting. “Something I’ve been doing for a couple of years now is starving
myself two days a week. . . . On Monday and Thursday, I eat fewer than five
hundred calories a day, then I eat like a pig for the other five days. You
‘surprise’ the body, keep it guessing.”
Not long ago, such fasting behaviors might have warranted the label “eating
disorder.” Too few calories is harmful for obvious reasons. But today,
fasting in some circles is considered normal and even healthy.
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What about exercise?
Exercise is immediately toxic to cells, leading to increased temperatures,
noxious oxidants, and oxygen and glucose deprivation. Yet the evidence is
overwhelming that exercise is health-promoting, and the absence of exercise,
especially combined with chronic sedentary feeding—eating too much all
day long—is deadly.
Exercise increases many of the neurotransmitters involved in positive
mood regulation: dopamine, serotonin, norepinephrine, epinephrine,
endocannabinoids, and endogenous opioid peptides (endorphins). Exercise
contributes to the birth of new neurons and supporting glial cells. Exercise
even reduces the likelihood of using and getting addicted to drugs.
When rats were given access to a running wheel six weeks prior to gaining
free access to cocaine, they self-administered the cocaine later and less often
than rats who had not had prior wheel training. This finding has been
replicated with heroin, methamphetamine, and alcohol. When exercise is not

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voluntary but rather forced on the animal, it still results in reduced voluntary
drug consumption.
In humans, high levels of physical activity in junior high, high school, and
early adulthood predict lower levels of drug use. Exercise has also been
shown to help those already addicted to stop or cut back.
Dopamine’s importance to motor circuits has been reported for every
animal phylum in which it has been investigated. The nematode C. elegans, a
worm and one of the simplest laboratory animals, releases dopamine in
response to environmental stimuli signaling the local abundance of food.
Dopamine’s ancient role in physical movement relates to its role in
motivation: To obtain the object of our desire, we need to go get it.
Of course today’s easy-access dopamine doesn’t require us to get off the
couch. According to survey reports, the typical American today spends half
their waking hours sitting, 50 percent more than fifty years ago. Data from
other rich nations around the globe are comparable. When you consider that
we evolved to traverse tens of kilometers daily to compete for a limited
supply of food, the adverse effects of our modern sedentary lifestyle are
devastating.
I sometimes wonder if our modern predilection for becoming addicted is
fueled in part by the way drugs remind us that we still have bodies. The most
popular video games feature avatars that run, jump, climb, shoot, and fly. The
smartphone requires us to scroll through pages and tap on screens, cleverly
exploiting ancient habits of repetitive motion, possibly acquired through
centuries of grinding wheat and picking berries. Our contemporary
preoccupation with sex may be because it’s the last physical activity still
widely practiced.
A key to well-being is for us to get off the couch and move our real bodies,
not our virtual ones. As I tell my patients, just walking in your neighborhood
for thirty minutes a day can make a difference. That’s because the evidence is
indisputable: Exercise has a more profound and sustained positive effect on
mood, anxiety, cognition, energy, and sleep than any pill I can prescribe.
—

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But pursuing pain is harder than pursuing pleasure. It goes against our innate
reflex to avoid pain and pursue pleasure. It adds to our cognitive load: We
have to remember that we will feel pleasure after pain, and we’re
remarkably amnestic about this sort of thing. I know I have to relearn the
lessons of pain every morning as I force myself to get out of bed and go
exercise.
Pursuing pain instead of pleasure is also countercultural, going against all
the feel-good messages that pervade so many aspects of modern life. Buddha
taught finding the Middle Way between pain and pleasure, but even the
Middle Way has been adulterated by the “tyranny of convenience.”
Hence we must seek out pain and invite it into our lives.