SUNDAY, Jan. 30 (HealthDayNews) -- Aerobic exercise alone can have a significant impact on mild to moderate depression, says a study by researchers at the University of Texas Southwestern Medical Center.

The study found that taking part in 30-minute aerobic exercise sessions three to five times a week reduced depressive symptoms by nearly 50 percent in adults aged 20 to 45. The results are comparable to findings from studies in which people with mild to moderate depression were treated with antidepressants or cognitive therapy.

"The effect you find using aerobic exercise alone in treating clinical depression is similar to what you find with antidepressant medications. The key is the intensity of the exercise and continuing it for 30 to 35 minutes per day. It's not for the faint of heart," study co-author Dr. Madhukar Trivedi, director of UT Southwestern's mood disorders research program, said in a prepared statement.

The study appears in the January issue of the American Journal of Preventive Medicine.

"Numerous effective treatments for depression are available, yet many people don't seek treatments for depression because of the negative social stigma still associated with the disease. Exercise may offer a viable treatment alternative, particularly as it can be recommended for most individuals," Trivedi said.