More exercise wasn't better against postpartum depression

Postpartum depression strikes at a vulnerable moment when many new mothers are reluctant or unable to take medication, which makes exercise an appealing option. But past studies of aerobic exercise for postpartum depression have disagreed, with some showing clear benefit and others very little, and nobody had pinned down whether the type, frequency, intensity or setting of the exercise explains the gap. This review set out to pool the trial evidence and, using network methods that rank different exercise prescriptions against each other, to work out what an effective programme actually looks like.

The researchers searched five databases for trials of aerobic exercise in the prevention or treatment of postpartum depression, registering the review in advance. Twenty-six studies with 2,867 participants were included. Standard pooling compared aerobic exercise against usual care on depression scores, while subgroup analyses probed supervised versus unsupervised and team versus individual formats, and a network meta-analysis ranked combinations of session length, intensity and weekly frequency against each other.

Aerobic exercise beat standard care on postpartum depression scores overall, with the caveat that the included trials disagreed with each other substantially. Prevention and treatment appeared to work differently, with the authors noting a greater emphasis on prevention, and this split explained some of the disagreement between trials. Moderate-intensity sessions of 35 to 45 minutes ranked above both shorter high-intensity and longer low-intensity formats, and a frequency of 3 to 4 sessions per week outperformed both 1 to 2 and 5 to 6 sessions. Supervised and team-based exercise looked slightly better than unsupervised and individual formats, but those differences were not statistically significant, and no single type of aerobic exercise beat the others.

The headline result confirms what smaller bodies of evidence have suggested: aerobic exercise helps with postpartum mood, perhaps more in prevention than in treatment. The more useful contribution is the dose-ranking, which pushes back against the assumption that more is always better, since 5 to 6 weekly sessions ranked below 3 to 4. The authors themselves urge caution: trials varied widely, several comparisons were indirect, and factors such as supervision and group settings could not be confirmed as genuine enhancers. Larger, more uniform trials are needed before the sweet spot can be treated as settled.

For a new mother weighing up how to protect her mood, this is evidence that aerobic exercise is a credible option, and that an achievable schedule may serve better than an exhausting one. The ranking that favoured 3 to 4 moderate sessions a week over near-daily exercise is worth knowing, especially at a life stage when time and sleep are scarce. No particular type of aerobic exercise stood out, so the form it takes may matter less than that it happens. As with any depression finding, this informs a conversation with a professional rather than replacing one.