There`s now sufficient research data to provide specific guidance on how to prescribe exercise for people with major depressive disorder (MDD), according to researchers including an Indian origin.

Despite the substantial evidence supporting the use of exercise in the treatment of MDD, previous studies have not provided a clear indication of the proper dose of exercise needed to elicit an antidepressant effect, noted Chad Rethorst, PhD, and Madhukar Trivedi, MD, of the Department of Psychiatry at the University of Texas Southwestern Medical Center, Dallas.

To fill this gap, the researchers reviewed available data from randomized controlled trials, with the goal of developing specific and detailed recommendations for clinicians on how to prescribe exercise for their patients with MDD.

Randomised trials have shown that exercise is effective in reducing depressive symptoms in patients with MDD, on its own and in conjunction with other treatments, such as antidepressant medication and/or psychotherapy.

Exercise may help to meet the need for cost-effective and accessible alternative therapies for depressive disorders-particularly for the substantial number of patients who don`t recover with currently available treatments.

Based on the available data, aerobic exercise is the preferred form of exercise for patients with MDD-although there is also support for resistance training, Drs Rethorst and Trivedi noted.

In terms of session frequency and duration, they recommend that patients participate in three to five exercise sessions per week, for 45 to 60 minutes per session.

In terms of intensity, for aerobic exercise, they recommend achieving a heart rate that is 50 to 85 percent of the individual`s maximum heart rate (HRmax). For resistance training, they recommend a variety of upper and lower body exercises, three sets of eight repetitions at 80 percent of 1-repetition maximum (RM-that is, 80 percent of the maximum weight that the person can lift one time).

Data suggest that patients may experience improvement in depressive symptoms as little as four weeks after starting exercise. However, Drs Rethorst and Trivedi emphasize that the exercise program should be continued for at least ten to twelve weeks to achieve the greatest antidepressant effect.

Some people have questioned whether patients with MDD will be willing to participate in an exercise program. But Drs Rethorst and Trivedi noted that, in the studies they reviewed, only about fifteen percent of patients dropped out of exercise programs-comparable to dropout rates in studies of medications and psychotherapy.

They discuss strategies that may help improve adherence to exercise programs, such as consulting patients about their preferred types of exercise and providing individualized educational materials and feedback.
They also provide some practical tips for clinicians on how to estimate exercise intensity using readily available information.

Even if the depressed patient can`t reach the target intensity and frequency levels, exercise can still be helpful.

"Taken as a whole, these findings suggest that exercise doses below the current recommendations may still be beneficial for patients with MDD," Drs Rethorst and Trivedi added.

The results were published in the May Journal of Psychiatric Practice .