WEST PALM BEACH, Fla. (Cox News Service) - Yet another study has been released showing the benefits of exercise. But before you hem and haw, hear this: Researchers at Berlin's Free University found that just a half-hour a day on a treadmill substantially improved the moods of patients with major depression.

It was a small study - only 12 patients - but 10 of the patients had been treated previously with two different antidepressants without improvement.

The results were reported recently in the British Journal of Sports Medicine.

The researchers were spurred to evaluate depressed patients after noticing positive mood results in bone-marrow transplant patients who took part in an earlier study of the effects of exercise on their physical performance.

Doctors found exercise resulted in similar mood uplifting in depressed patients.

``At the end of the training program, we observed a substantial improvement in six patients and a slight improvement in two; the severity of symptoms was unchanged in four patients,'' the report said.

``Our results indicate that, in selected patients with major depression, aerobic training can produce a substantial improvement in symptoms in a short time.''

This is encouraging news, since antidepressants can take anywhere from two to four weeks before any therapeutic effect is felt, and in some patients, no improvement is ever shown.

``For these patients, aerobic training could offer a safe therapeutic option,'' the doctors said.

Researchers chalked up the findings to the traditionally accepted notion that exercise produces changes in biology that improve mood. But they also evaluated factors such as motivation, expectancy and human contact.

``At the time of participation in the study, most of the patients had been taking part in a program of therapeutic activities - for example, work or occupational therapy - for several months without any improvement in symptoms. Therefore, we feel that psychological or motivational factors alone cannot fully explain the observed outcomes.''

You have to think if exercise could benefit people who were clinically depressed, it can certainly elevate mood in people who have more garden-variety blues.

Coincidentally, last month's Mayo Clinic newsletter reported findings in the Journal of Aging and Physical Activity that showed regular exercise improved mood in people 65 and over.

The optimal combination for mood enhancement was strength training mixed with aerobics or other types of exercise. Studies like these make it increasingly difficult for our sedentary society to blow off the benefits of movement. And that movement doesn't even need to be strenuous.

The Journal of Aging found the most consistent improvement in mood among the elderly was with low-intensity exercise done fewer than three days a week, but for at least 45 minutes or more a session.

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