Exercise for Mood: Real Effect, Smaller Than the Headlines

Summary

Exercise is a genuinely effective, prescribable lever for low mood and mild-to-moderate depression — **Tier 1 (Strong Evidence)**, with a real moderate average effect (headline SMD roughly **−0.4 to −0.6** versus control) that is comparable to antidepressants or therapy for milder presentations and adds value on top of medication; but the magnitude is systematically inflated by unblinded, self-report trials, shrinking to **small and non-significant in the highest-quality studies** (Cochrane: −0.62 across all trials → **−0.18, not significant** in the six most robust), so the honest claim is "r