Early antidepressant effects of supervised Nordic walking in adults with moderate to severe depression: A randomized controlled trial

Background Physical exercise is an effective treatment for depression, yet little is known about the temporal dynamics of symptom improvement during exercise interventions. Methods In this randomized controlled trial, 64 adults with moderate to severe depressive symptoms were allocated to a 10-week supervised Nordic walking (NW) program ( n = 48) or a non-active control condition ( n = 16). The NW group completed two weekly training sessions at moderate intensity (65–75% HRmax). Depressive symptoms were assessed at baseline, mid-intervention (Week 5), and post-intervention (Week 10) using the Beck Depression Inventory-II. Primary analyses examined Group × Time effects on symptom severity. Secondary analyses explored (via a Group × Depression intensity × Time ANOVA) whether baseline depression intensity moderated treatment response. Results A significant Group × Time interaction indicated greater reductions in depressive symptoms in the NW group compared with controls. Symptom improvement was most pronounced during the first half of intervention (Hedges's g = −0.98), with smaller changes thereafter (Hedges's g = −0.40 from mid- to post-intervention). In addition, a significant Group × Depression intensity × Time interaction suggests that participants with severe baseline depression experienced larger and more rapid improvement than those with moderate symptoms in the first five weeks. Conclusions Supervised Nordic walking was found to be associated with substantial reductions in depressive symptoms within five weeks, particularly among individuals with severe depression. Implications of our findings and study's limitations are discussed.