Dopamine Nation

of Applied Physiology, conducted an experiment in which ten men
volunteered to submerge themselves (head out) in cold water (14 degrees
Celsius) for one hour. This is 57 degrees Fahrenheit.
Using blood samples, the researchers showed that plasma (blood)
dopamine concentrations increased 250 percent, and plasma norepinephrine
concentrations increased 530 percent as a result of cold-water immersion.
Dopamine rose gradually and steadily over the course of the cold bath and
remained elevated for an hour afterward. Norepinephrine rose precipitously
in the first thirty minutes, plateaued in the latter thirty minutes, and dropped
by about a third in the hour afterward, but it remained elevated well above
baseline even into the second hour after the bath. Dopamine and
norepinephrine levels endured well beyond the painful stimulus itself, which
explains Michael’s statement, “Right after I get out . . . I feel great for hours.”
Other studies examining the brain effects of cold-water immersion in
humans and animals show similar elevations in monoamine neurotransmitters

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(dopamine, norepinephrine, serotonin), the same neurotransmitters that
regulate pleasure, motivation, mood, appetite, sleep, and alertness.
Beyond neurotransmitters, extreme cold in animals has been shown to
promote neuronal growth, all the more remarkable since neurons are known
to alter their microstructure in response to only a small handful of
circumstances.
Christina G. von der Ohe and her colleagues studied the brains of
hibernating ground squirrels. During hibernation, both core and brain
temperatures drop to within 0.5–3 degrees Celsius. At freezing temperatures,
the neurons of hibernating ground squirrels look like spindly trees with few
branches (dendrites) and even fewer leaves (microdendrites).
As the hibernating ground squirrel is warmed, however, the neurons show
remarkable regrowth, like a deciduous forest at the height of spring. This
regrowth occurs rapidly, rivaling the kind of neuronal plasticity seen only in
embryonic development.
The study’s authors wrote of their findings: “The structural changes we
have demonstrated in the hibernator brain are among the most dramatic found
in nature. . . . Whereas dendritic elongation can reach 114 micrometers per
day in the hippocampus of the developing rhesus monkey embryo, adult
hibernators exhibit similar changes in just 2 hours.”
—
Michael’s accidental discovery of the benefits of ice-cold water immersion
is an example of how pressing on the pain side of the balance can lead to its
opposite—pleasure. Unlike pressing on the pleasure side, the dopamine that
comes from pain is indirect and potentially more enduring. So how does it
work?
Pain leads to pleasure by triggering the body’s own regulating homeostatic
mechanisms. In this case, the initial pain stimulus is followed by gremlins
hopping on the pleasure side of the balance.

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The pleasure we feel is our body’s natural and reflexive physiological
response to pain. Martin Luther’s mortification of the flesh through fasting
and self-flagellation may have gotten him a little bit high, even if it was for
religious reasons.
With intermittent exposure to pain, our natural hedonic set point gets
weighted to the side of pleasure, such that we become less vulnerable to pain
and more able to feel pleasure over time.
In the late 1960s, scientists conducted a series of experiments on dogs that,
due to the experiments’ obvious cruelty, would not be allowed today but

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nonetheless provide important information on brain homeostasis (or leveling
the balance).
After connecting the dog’s hind paws to an electrical current, the
researchers observed: “The dog appeared to be terrified during the first few
shocks. It screeched and thrashed about, its pupils dilated, its eyes bulged, its
hair stood on end, its ears lay back, its tail curled between its legs. Expulsive
defecation and urination, along with many other symptoms of intense
autonomic nervous system activity, were seen.”
After the first shock, when the dog was freed from the harness, “it moved
slowly about the room, appeared to be stealthy, hesitant, and unfriendly.” The
dog’s heart rate increased to 150 beats per minute above resting baseline
during the first shock. When the shock was over, the dog’s heart rate slowed
to 30 beats below baseline for a full minute.
Over subsequent electric shocks, “its behavior gradually changed. During
shocks, the signs of terror disappeared. Instead, the dog appeared pained,
annoyed, or anxious, but not terrified. For example, it whined rather than
shrieked, and showed no further urination, defecation, or struggling. Then,
when released suddenly at the end of the session, the dog rushed about,
jumped up on people, wagged its tail, in what we called at the time ‘a fit of
joy.’ ”
With subsequent shocks, the dog’s heart rate rose only slightly above
resting baseline, and then only for a few seconds. After the shock was over,
the heart rate slowed massively to 60 beats per minute below resting
baseline, double the first time. It took a full five minutes for the heart rate to
return to resting baseline.
With repeated exposure to a painful stimulus, the dog’s mood and heart rate
adapted in kind. The initial response (pain) got shorter and weaker. The
after-response (pleasure) got longer and stronger. Pain morphed into
hypervigilance morphed into a “fit of joy.” An elevated heart rate, consistent
with a fight-or-flight reaction, morphed into minimal heart rate elevation
followed by prolonged bradycardia, a slowed heart rate seen in states of
deep relaxation.

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It’s not possible to read this experiment without feeling pity for the animals
subjected to this torture. Yet the so-called “fit of joy” suggests a tantalizing
possibility: By pressing on the pain side of the balance, might we achieve a
more enduring source of pleasure?
This idea is not new. Ancient philosophers observed a similar
phenomenon. Socrates (as recorded by Plato in “Socrates’ Reasons for Not
Fearing Death”) mused on the relationship between pain and pleasure more
than two thousand years ago:
How strange would appear to be this thing that men call pleasure! And
how curiously it is related to what is thought to be its opposite, pain!
The two will never be found together in a man, and yet if you seek the
one and obtain it, you are almost bound always to get the other as well,
just as though they were both attached to one and the same head. . . .
Wherever the one is found, the other follows up behind. So, in my
case, since I had pain in my leg as a result of the fetters, pleasure
seems to have come to follow it up.
The American cardiologist Helen Taussig published an article in American