Imagine a depression treatment (search) that soothed the mind and emotions, protected the heart and zapped away excess weight — without side effects.

Sound too good to be true? It’s not. Such a remedy already exists, and it doesn’t come in a pill bottle, say experts from the University of Texas Southwestern Medical Center.

Aerobic exercise can make a big difference in mild to moderate depression, say Andrea Dunn, PhD, and colleagues in the American Journal of Preventive Medicine’s January edition.

The researchers found that 30-minute aerobic workouts of moderate intensity, done three to five times weekly, cut mild to moderate depression symptoms nearly in half. That’s comparable to other depression treatments, say researchers.

Depression Common, Treatment Rare

In any given year, nearly 19 million adults in America have a depressive illness, says the National Institute of Mental Health. That’s more than 9 percent of the population.

Many suffer silently, not getting treatment that could help.

Only 23 percent of depressed people seek treatment and just 10 percent receive adequate treatment. That’s partly due to social stigma associated with treatment, say the researchers.

With that in mind, they studied a socially accepted antidepressant — exercise. Studies have shown that exercise can help relieve depression, but no one knew exactly how well it worked.

Participants were 80 adults with mild to moderate depression. All were 20 to 45 years old. None were taking other depression treatments.

Fitness Makeover

The participants signed on for a major fitness overhaul. Before the study, they were largely sedentary, working out less than three times weekly for no more than 20 minutes per session.

Those couch-potato days vanished when the 12-week study began. Participants were randomly assigned to one of five groups to test different fitness strategies.

Two groups did moderate aerobic exercise. One group worked out 3 days per week; the other group exercised 5 days per week. They worked out on treadmills or stationary bikes.

The other groups took it a bit easier. Two groups did low-intensity aerobic workouts for 3 or 5 days weekly. For comparison, the last group didn’t do any aerobic exercise. Instead, they stretched and did flexibility exercises for 15 to 20 minutes 3 days per week.

Cheating was out of the question. Everyone exercised under the watchful eye of fitness pros at the Cooper Institute in Dallas.

Exercise Equals Talk Therapy, Drugs

After 12 weeks, participants were rescreened for depression symptoms. All three groups had lower scores than at the beginning of the study.

The moderate-intensity groups had the biggest improvement. Their symptoms fell by 47 percent. In addition, depression had gone into remission for 42 percent of those participants, according to their depression test scores.

That’s comparable to other depression treatments, say the researchers. They cite remission rates of 36 percent for cognitive behavior therapy and 42 percent for the antidepressant medication Tofranil (search) (imipramine) – an older antidepressant — in other studies.

Lower-intensity aerobic exercise and stretching/flexibility weren’t as beneficial. Low-intensity exercise cut depression symptoms by 30 percent, compared to 29 percent for stretching/flexibility.

It didn’t matter whether the workouts were done three or five days per week.

“The key is the intensity of the exercise and continuing it for 30-35 minutes per day,” says psychiatry professor Madhukar Trivedi, MD. Trivedi worked on the study and directs the university’s mood disorders research program.

Keep in mind that this study focused on mild to moderate depression in younger adults. It didn’t address severe depression, or other groups of patients.

Depression is a serious illness affecting the whole body and deserves professional help. No one suggests trading talk therapy or prescription drugs for gym memberships. Instead, exercise might be one more option to consider in planning treatment. It’s also a good idea to get your general health checked out before launching a new fitness program.

By Miranda Hitti, reviewed by Michael W. Smith, MD

SOURCES: Dunn, A., American Journal of Preventive Medicine, January 2005; vol 28: pp 1-8. National Institutes for Mental Health, “Depression.” News release, University of Texas Southwestern Medical Center at Dallas.