Jennifer Lovejoy, Arivale Chief Science Officer, PhD
There are some clear physical benefits associated with resistance exercise training–or RET–including increased strength, skeletal muscle mass, and endurance. But, according to new research, those benefits may extend to mental health, specifically as it pertains to depression.
While the mental health benefits of acute aerobic exercise are well established, a meta-analysis published May 9 in JAMA Psychiatry and covered by Time suggests RET, which includes weightlifting and strength training, can have a positive effect on the symptoms of depression.
Researchers did a meta-analysis–an analysis that combines the results from previous studies–on 33 already-conducted clinical trials covering 1,877 individuals. They found RET was associated with a statistically significant reduction in depressive symptoms, including loss of interest in activities, feelings of worthlessness, and poor mood.
Improvement in depressive symptoms was seen regardless of the participants’ characteristics–age, sex, and health status–or the type of RET they performed–duration, intensity, frequency, and so on. The positive results even held regardless of any change participants saw in their physical strength.
Additional analyses showed that significantly larger improvements in depressive symptoms were seen in trials of participants with mild to moderate depressive symptoms compared with trials of participants without such symptoms. Similarly, larger improvements were noted in trials of shorter RET sessions (less than 45 minutes) compared with trials of longer sessions.
Those previous clinical trials documented improvements in depressive symptoms in participants utilizing a wide range of RET programs, so the lead author of the meta-analysis recommends sticking with the guidelines provided by the American College of Sports Medicine: perform eight to 12 repetitions of eight to 10 strength-building exercises at least twice per week.
As with most studies, there are some limitations worth noting.
First–and not noted in the Time article–there were substantial differences in the study design and/or patient populations between the 33 trials. This suggests the results from those trials aren’t directly comparable to one another and the overall result from the meta-analysis should be interpreted with some caution. Furthermore, many trials failed to clearly or completely report on intervention design, analysis, and participant information, such as antidepressant use.
Second, the meta-analysis doesn’t tell us how RET seems to alleviate depressive symptoms.
Lastly, the Time article mentions that RET “seems to work as well as the frontline treatments for depression—antidepressants and behavioral therapies.” The meta-analysis doesn’t actually make any comparisons between RET and antidepressants or RET and behavioral therapies, likely because there haven’t been many trials to do so. Without such comparisons, it’s difficult to draw conclusions on how RET compares to a more clinically standard therapy for depression.
It’s important to note that while exercise may help alleviate the symptoms of depression, it may not necessarily take the place of prescribed medication or therapy. One should work with their physician to treat depression or depressive symptoms.