Weight Gain Linked to Stress
Exercise Stress Away
It's Only Natural: Our Innate Response to Stress continued...
When we experience something stressful, our brains release a
substance known as corticotropin-releasing hormone (CRH), which puts the body
on alert and sends it into "fight or flight" mode. As the body gears up
for battle, the pupils dilate, thinking improves, and the lungs take in more
oxygen. But something else happens as well: Our appetite is suppressed, and the
digestive system shuts off temporarily. CRH also triggers the release of the
hormones adrenaline and cortisol, which help mobilize carbohydrate and fat for
quick energy. When the immediate stress is over, the adrenaline dissipates, but
the cortisol lingers to help bring the body back into balance. And one of the
ways it gets things back to normal is to increase our appetites so we can
replace the carbohydrate and fat we should have burned while fleeing or
"But when was the last time you responded to stress with
such physicality?" Peeke asks. In today's modern world, this elegant
survival mechanism may be an anachronism that causes the body to refuel when it
doesn't need to.
Yet, it's not just quick, unsettling episodes that can prove
problematic, says Peeke. Feeling stressed-out over a long period of time may be
fattening, too: Sustained stress keeps cortisol, that cursed hunger promoter,
elevated and that keeps the appetite up, too.
And there's another factor as well. If stress and cortisol
levels stay high, so will insulin levels, says Robert M. Sapolsky, PhD, a
professor of biological sciences and neuroscience at Stanford University.
"The net effect of this will be increased fat deposition in a certain part
of the body."
And that body part generally is the waistline. A recent study
conducted by researchers at Yale University and published in the September 2000
issue of Psychosomatic Medicine compared 30 women who stored fat
primarily in their abdomens with 29 women who stored it mostly in their hips.
They found that the women with belly fat reported feeling more threatened by
stressful tasks and having more stressful lives. They also produced higher
levels of cortisol than the women with fat on their hips. And that, the authors
reasoned, suggests that cortisol causes fat to be stored in the center of the