Updated Sunday, November 4, 2012 at 04:31 PM
/ AUSTIN, Texas — If University of Texas engineering professor Jack Lee misses swim practice for a few days, his wife nudges him out the door.
"Go swimming," she tells him. "You're getting cranky."
As anyone who exercises regularly can tell you, some hearty sweating can calm frazzled nerves and ease a case of the grumps.
Turns out there are physiological reasons for that, beyond the runner's high caused by a rush of endorphins.
Studies published by the American Psychological Association show that exercise improves the body's ability to cope with stress. People who exercise also have lower rates of anxiety and depression.
Hormones like norepinephrine, secreted by the adrenal gland, some sympathetic nerve endings and even the brain, should get some of the credit, says Kay Allensworth, an Austin psychologist who specializes in critical-incident stress management.
When something stressful happens — an unexpected noise in the middle of the night, for example — the pituitary gland sends out a hormone that courses through the blood, reaching the adrenal gland in about 8 seconds. The adrenal gland, in turn, produces epinephrine, which spurs the "fight or flight" response. The pupils dilate, blood pressure increases, the hearing becomes more acute and blood flow increases to the heart and brain and decreases to the extremities and stomach.
"It's a storm that hits you," says Allensworth.
Centuries ago, that response happened only occasionally. "In modern times, that starts happening more and more often. It takes less and less to stimulate epinephrine," Allensworth says.
Not that getting stressed is all bad. It's not doing anything about it that wreaks havoc.
Exercise can help. Exercise spurs the creation of norepinephrine, which acts as a brain stress "buffer," keeping levels of epinephrine and cortisol, another stress hormone, under control.
Small jolts of cortisol and epinephrine can be beneficial — they provide the jolt of energy needed to run away from a bear, for example. It also makes you less sensitive to pain and boosts memory functions.
But if your body doesn't reset to normal afterward, you can start to suffer from chronic stress. And that can lead to everything from sleepless nights, impaired cognitive performance or higher blood pressure.
That's why Allensworth, the Texas coordinator for the American Psychological Association's Public Education Committee on Mind/Body Health, recommends exercise to people coping with stressful events like the death of a loved one or fallout from a crime. Swimming or yoga, which both require focus on breathing, can be particularly helpful, she says, but almost any cardiovascular exercise, from running on a treadmill to working out on an elliptical machine or cycling, does the trick.
"If you know how to relieve the stress you can deal with it, because we're not going to get rid of the stress," Allensworth says. "Exercise and diet are the first things I mention. Those are the underpinnings of what keep us healthy."
Another way exercise helps? Exercise makes you sleep better. Think of the way your dog crashes after he's been chasing a ball or romping at the creek all afternoon.
Just be careful not to overdo it. Depending on your fitness level, even parking your car farther away and walking more can help. Others might need more vigorous exercise, like a short run or bike ride.
"Everyone wants a magic pill, but taking a pill really isn't taking care of yourself. It's putting a chemical in your body," Allensworth says. "Exercise inoculates you to stress naturally. It works better than pharmaceuticals."
Even some forms of conscious relaxation, which mimics exercise, can help.
Start by breathing deeply. Then, working from top to bottom, tense and release your muscles, a body part at a time. Contract your hand muscles, then relax them. Contract your forearms, then relax them. And so on.
Amp up the effect by thinking about someplace where you feel relaxed and happy.
Lee, 54, and his wife, a dentist, have two school-age children. He swims six or seven days a week. Besides keeping him physically fit, he says, swimming helps him keep his mind off the daily stresses of life.
"For the hour and a half we swim in the morning, we're forced to focus on the physical exercise," he says. "Swimming allows my mind to rest, which actually leads to more clear thinking."