Just 30 minutes of brisk walking can immediately boost the mood of depressed patients, giving them the same quick pick-me-up they may be seeking from cigarettes, caffeine or binge eating, a small study found.

Researchers at the University of Texas at Austin found that people suffering from depression who walked on a treadmill for 30 minutes reported feeling more vigorous and had a greater sense of psychological well-being for up to an hour after completing the workout.

Those patients and another group that sat quietly for 30 minutes both reported reductions in negative feelings such as tension, depression, anger and fatigue.

But only the group that exercised said they felt good after the session, according to the study, published in the December issue of the journal, Medicine and Science in Sports and Exercise.

Lead researcher John Bartholomew said the study reinforces past research that has found consistent exercise, along with medication and counseling, can help people overcome depression.

However, Bartholomew's is among the first to show that exercise can have a positive effect right away.

"It's not something you have to do for 10 weeks and it's not something you have to do at a high intensity," said Bartholomew, an associate professor of kinesiology and health education. "You should derive a benefit very early on in the process, and hopefully that is the kind of thing that will motivate them to continue to engage in the behavior."

The study, funded by Future Search Trials, an Austin medical research company, involved 40 people between the ages of 18 and 55. All were recently diagnosed with major depressive disorder, were not taking antidepressants and did not regularly exercise.

Twenty patients were assigned to exercise for 30 minutes, while the others sat quietly for the same amount of time. They were surveyed five minutes before the session and five, 30 and 60 minutes afterward.

The positive mood effects from walking were sizable, lifting their feelings of vigor to near-normal levels, the study said. But the results were short-lived, returning to pre-exercise levels within an hour.

While the study shows depressed people who self-medicate with cigarettes, caffeine or food binges could get similar positive feelings from exercising, experts said it won't be easy to persuade them to replace bad habits with walking or shooting hoops. It's hard enough to get healthy adults to exercise.

"For people who are severely depressed, that may not be something I'm really going to hang my hat on," said Dr. Erik Nelson, an assistant professor of clinical psychiatry at the University of Cincinnati College of Medicine.

But for mildly to moderately depressed patients, exercise may lessen feelings of helplessness and isolation, he said.

"People shouldn't feel like the only thing they can do is take their medicine and wait till they feel better," Nelson said. "This kind of shows there are things you can do to help yourself in the short term."