Background: The number of adults across the globe with significant depressive symptoms has grown substantially during the COVID-19 pandemic . The extant literature supports exercise as a potent behavior that can significantly reduce depressive symptoms in clinical and non-clinical populations .
Objective: Using a suite of mobile applications, at-home exercise, including high intensity interval training (HIIT) and/or yoga, was completed to reduce depressive symptoms in the general population in the early months of the pandemic .
Methods: A 6-week, parallel, multi-arm, randomized controlled trial was completed with 4 groups:  HIIT,  Yoga,  HIIT+Yoga, and  waitlist control (WLC). Low active, English-speaking, non-retired Canadians aged 18-64 years were included . Depressive symptoms were measured at baseline and weekly following randomization .
Results: A total of 334 participants were randomized to one of four groups . No differences in depressive symptoms were evident at baseline . The results of latent growth modeling showed significant treatment effects for each active group compared to the WLC, with small effect sizes in the community-based sample of participants . Treatment groups were not significantly different from each other . Effect sizes were very large when restricting analyses only to participants with high depressive symptoms at baseline .
Conclusions: At-home exercise is a potent behavior to improve mental health in adults during the pandemic, especially in those with increased levels of depressive symptoms . Promotion of at-home exercise may be a global public health target with important personal, social, and economic implications as the world emerges scathed by the pandemic.