REVIEW OF: Tian S et al, J Psychiatr Res 2024;176:384–392

STUDY TYPE: Systematic review and meta-analysis 

Exercise is an adjunct therapy for major depressive disorder (MDD) (Xie Y et al, Front Psychiatry 2021;12:705559). We know it can help—but what kind, how much, and how often?

Researchers analyzed data from 46 RCTs involving 3,164 adults with MDD or dysthymia. They wanted to determine the optimal exercise type and dose for reducing symptoms. They evaluated four exercise types—mind-body (for strengthening mental and physical connections, such as tai chi, yoga, or qigong), aerobic, resistance, and mixed aerobic and resistance. These were compared against a control of no exercise.

All exercise modalities reduced depression when maintained for more than four weeks. There was no statistically significant difference between them. The aggregate maximum effective dose was 245 minutes of walking, 140 minutes of aerobic exercise, or 215 minutes of yoga per week (the authors didn’t provide an equivalent mixed or resistance threshold). More exercise than this was associated with less-robust improvements in depressed symptoms. 

CARLAT TAKE
All sorts of exercise can benefit depressed patients. This study suggests that patients could aim for very specific weekly targets. However, this quantification was not the product of direct comparison and should not be seen as a universal clinical goal. Start where patients are at, encourage a healthy, sustainable habit, and don’t worry too much about exact numbers.