Stress Takes a Toll on the Brain But Exercise Can Help

Stress can wreak havoc on your body. It also can harm your brain.

Whether it's short-term stress (17 people are coming for dinner and your oven just went on the blink) or long-term stress (a loved one is seriously ill), the body releases powerful fight-or-flight stress hormones (adrenaline, cortisol).

While these hormones do sharpen attention and spur us to take needed action, humans weren't designed to handle high levels of stress hormones day after day, year after year.

Indeed, in the brain those stress hormones weaken blood vessels, kill off neurons and even shrink the hippocampus, a known risk factor for Alzheimer's disease. But there are ways to fight back.

"Exercise is essential for anyone under chronic stress, and that includes most of us," says Elissa Epel, a professor of psychiatry at the University of California, San Francisco. Exercise short-circuits the stress response by triggering the release of BDNF (brain-derived neurotrophic factor), which nourishes cell growth, as well as endorphins (serotonin, dopamine and norepinephrine), brain chemicals that boost feelings of well-being, ease muscle tension and improve sleep.

The cognitive functions and brain regions showing the most significant decay in late adulthood are the same regions that may benefit the most from exercise, says Benjamin L. Willis,  an epidemiologist at the Cooper Institute in Dallas and coauthor of a long-term study highlighting the importance of exercise in reducing dementia risk.

So don't procrastinate: Carve out 150 minutes a week of moderate aerobic exercise. Couch potatoes should start slowly — 10 to 15 minutes every other day, working up to 30 to 45 minutes, five days a week. After all, you're not competing in Olympic trials. Just walk briskly, jog, swim or bike — anything you enjoy doing that gets your heart pumping a bit faster and makes you break a sweat.

A study by Scottish researchers found that simply strolling through a green leafy park, as opposed to the concrete jungle of a busy city, actually lowers cortisol levels in the brain, easing "brain fatigue."

Don't forget resistance training (20 minutes every other day, using exercise bands or light weights) to boost muscle tone, balance and flexibility. Never done any of that? You can sign up for an orientation class at a health club, but push-ups (on the floor, against a wall) and squats in your living room work, too.