From Science Daily
People suffering from depression feel better if they do weight training, researchers at Harvard Medical School discovered in the 1990s. The heavier the weights they used, the greater the effect the strength training had on the level of depression.
That intensive exercise can help reduce depression was already known in the late nineties. Most of the research was done on people with depression who started running and who showed marked improvement after a few weeks. While the studies did not show that this cured depression, they did show that people whose functioning was impaired by moderate depression could reduce their symptoms and resume work again.
The Harvard researchers only found two studies in which researchers had got people with depression to do weight training. [Compr Psychiatry. 1989 Jul-Aug; 30(4): 324-31.] [Consult Clin Psychol. 1987 Oct; 55(5): 748-54.] The effects measured in these two studies, however, exceeded the average effect of the studies in which subjects had gone running.
The Harvard researchers made a cursory repeat of the studies. They chose 15 people in their sixties who were suffering from depression but were not being treated by psychiatrists. A similar group of 17 over-sixties formed the control group.
The experimental group trained three times a week for 10 weeks, doing five exercises for the largest muscle groups: bench-press, lat-pulldown, leg-press, leg-extension and leg-curl. The participants did 3 sets of 8 reps for each exercise. The researchers encouraged the subjects to train at 80 percent of the weight with which they were just able to do 1 rep [1RM]. Each workout lasted 45 minutes, after which the subjects did stretches.
At the end of the 10 weeks the subjects who had trained were in a better frame of mind than the subjects in the control group. The Exercise group scored better for the Beck Depression Inventory [BDI] and for the Hamilton Rating Scale For Depression [HRSD] at the end of the 10 weeks.
The researchers also kept track of the amount of weight that the subjects used in their workouts. The subjects trained at an average of 78 percent of their 1RM. The researchers discovered that the heavier the weights the subjects used the more they could reduce their level of depression.
The researchers are positive about the results of their study. They measured strong positive effects and there was considerable improvement in the subjects' quality of life.
J Gerontol A Biol Sci Med Sci. 1997 Jan;52(1):M27-35.