The Exercise Effect

When Jennifer Carter, PhD, counsels patients, she often suggests they walk as they talk. "I work on a beautiful wooded campus," says the counseling and sport psychologist at the Center for Balanced Living in Ohio.

Strolling through a therapy session often helps patients relax and open up, she finds. But that's not the only benefit. As immediate past president of APA's Div. 47 (Exercise and Sport Psychology), she's well aware of the mental health benefits of moving your muscles. "I often recommend exercise for my psychotherapy clients, particularly for those who are anxious or depressed," she says.

Unfortunately, graduate training programs rarely teach students how to help patients modify their exercise behavior, Carter says, and many psychologists aren't taking the reins on their own. "I think clinical and counseling psychologists could do a better job of incorporating exercise into treatment," she says.

"Exercise is something that psychologists have been very slow to attend to," agrees Michael Otto, PhD, a professor of psychology at Boston University. "People know that exercise helps physical outcomes. There is much less awareness of mental health outcomes — and much, much less ability to translate this awareness into exercise action."

Researchers are still working out the details of that action: how much exercise is needed, what mechanisms are behind the boost exercise brings, and why — despite all the benefits of physical activity — it's so hard to go for that morning jog. But as evidence piles up, the exercise-mental health connection is becoming impossible to ignore.

Mood enhancement

If you've ever gone for a run after a stressful day, chances are you felt better afterward. "The link between exercise and mood is pretty strong," Otto says. "Usually within five minutes after moderate exercise you get a mood-enhancement effect."

But the effects of physical activity extend beyond the short-term. Research shows that exercise can also help alleviate long-term depression.

Some of the evidence for that comes from broad, population-based correlation studies. "There's good epidemiological data to suggest that active people are less depressed than inactive people. And people who were active and stopped tend to be more depressed than those who maintain or initiate an exercise program," says James Blumenthal, PhD, a clinical psychologist at Duke University.

Fight-or-flight

Researchers have also explored exercise as a tool for treating — and perhaps preventing — anxiety. When we're spooked or threatened, our nervous systems jump into action, setting off a cascade of reactions such as sweating, dizziness, and a racing heart. People with heightened sensitivity to anxiety respond to those sensations with fear. They're also more likely to develop panic disorder down the road, says Jasper Smits, PhD, Co-Director of the Anxiety Research and Treatment Program at Southern Methodist University in Dallas and co-author, with Otto, of the 2011 book "Exercise for Mood and Anxiety: Proven Strategies for Overcoming Depression and Enhancing Well-being."

Smits and Otto reasoned that regular workouts might help people prone to anxiety become less likely to panic when they experience those fight-or-flight sensations. After all, the body produces many of the same physical reactions — heavy perspiration, increased heart rate — in response to exercise. They tested their theory among 60 volunteers with heightened sensitivity to anxiety. Subjects who participated in a two-week exercise program showed significant improvements in anxiety sensitivity compared with a control group (Depression and Anxiety, 2008). "Exercise in many ways is like exposure treatment," says Smits. "People learn to associate the symptoms with safety instead of danger."

Therein lies the problem with prescribing exercise for mental health. Researchers don't yet have a handle on which types of exercise are most effective, how much is necessary, or even whether exercise works best in conjunction with other therapies.

"Mental health professionals might think exercise may be a good complement [to other therapies], and that may be true," says Blumenthal. "But there's very limited data that suggests combining exercise with another treatment is better than the treatment or the exercise alone."

Buffering the brain

It's also unclear exactly how moving your muscles can have such a significant effect on mental health. "Biochemically, there are many things that can impact mood. There are so many good, open questions about which mechanisms contribute the most to changes in depression," says de Groot.

Some researchers suspect exercise alleviates chronic depression by increasing serotonin (the neurotransmitter targeted by antidepressants) or brain-derived neurotrophic factor (which supports the growth of neurons). Another theory suggests exercise helps by normalizing sleep, which is known to have protective effects on the brain.

There are psychological explanations, too. Exercise may boost a depressed person's outlook by helping him return to meaningful activity and providing a sense of accomplishment. Then there's the fact that a person's responsiveness to stress is moderated by activity. "Exercise may be a way of biologically toughening up the brain so stress has less of a central impact," Otto says.

It's likely that multiple factors are at play. "Exercise has such broad effects that my guess is that there are going to be multiple mechanisms at multiple levels," Smits says.

Getting the payoff

Of all the questions that remain to be answered, perhaps the most perplexing is this: If exercise makes us feel so good, why is it so hard to do it? According to the Centers for Disease Control and Prevention, in 2008 (the most recent year for which data are available), some 25 percent of the U.S. population reported zero leisure-time physical activity.

Starting out too hard in a new exercise program may be one of the reasons people disdain physical activity. When people exercise above their respiratory threshold — that is, above the point when it gets hard to talk — they postpone exercise's immediate mood boost by about 30 minutes, Otto says. For novices, that delay could turn them off of the treadmill for good. Given that, he recommends that workout neophytes start slowly, with a moderate exercise plan.

Otto also blames an emphasis on the physical effects of exercise for our national apathy to activity. Physicians frequently tell patients to work out to lose weight, lower cholesterol or prevent diabetes. Unfortunately, it takes months before any physical results of your hard work in the gym are apparent. "Attending to the outcomes of fitness is a recipe for failure," he says.

The exercise mood boost, on the other hand, offers near-instant gratification. Therapists would do well to encourage their patients to tune into their mental state after exercise, Otto says — especially when they're feeling down.

"Many people skip the workout at the very time it has the greatest payoff. That prevents you from noticing just how much better you feel when you exercise," he says. "Failing to exercise when you feel bad is like explicitly not taking an aspirin when your head hurts. That's the time you get the payoff."

It may take a longer course of exercise to alleviate mood disorders such as anxiety or depression, Smits adds. But the immediate effects are tangible — and psychologists are in a unique position to help people get moving. "We're experts in behavior change," he says. "We can help people become motivated to exercise."