Weight training can help shape the body and also the mind, studies show

Could lifting weights take a weight off the mind? Yes, said a newly published analysis of dozens of studies that looked at mood disorders.

Exercise can help improve symptoms of depression, the analysis found -- and not just aerobic exercises like running, jazzercise or cardio machines.

Whether it's the weight room or the mat, the authors of the study published Wednesday in the Journal of the American Medical Association, said resistance training can also help people suffering with depression.

More than 300 million people worldwide are affected by depression, according to the World Health Organization, which can be a debilitating and costly problem. First-line treatments are usually medications and psychotherapy, which work for many, but can also be expensive and time-consuming.

Plus, the authors found that almost 70 percent of patients in the studies still reported feeling down for up to 14 weeks after starting therapy -- and close to a third of patients had to try four different medications to get relief.

Researchers from Ireland and Sweden pooled the data from 1,877 patients and 33 randomized clinical trials measuring how resistance training affects mood. The patients worked out, 3 sessions per week, for an average of 16 weeks. The intensity of the exercise was mixed, but it wasn't an Olympic effort -- most were putting in low to moderate effort, and ranged in age from their 20s to their 80s.

Resistance training -- everything from arm raises and leg lifts to weight training -- alleviated depression symptoms, study participants said. The largest gains were made by patients who reported mild to moderate depression.

The analysis was limited in some ways. These were a mix of studies and not every study had the same forms of resistance training or the same amount of information about the specific exercises. Only a few studies compared aerobic to resistance exercises -- and found there was no difference.

Improvements in mood did not depend on how much exercise was done, baseline health or the amount of strength gained from the exercise program, the authors found. The important thing was to just do it.

Sunny Intwala, M.D., is a third-year Cardiology fellow affiliated with Boston University School of Medicine and a Clinical Exercise Physiologist who works in the ABC News Medical Unit.