A longitudinal study on depressive symptoms and physical activity during the Spanish lockdown.

: The aim was to evaluate the evolution of depressive symptoms and to explore the influence of physical activity (PA) practice during the home confinement due to the COVID-19 outbreak in Spain. : Information was collected from 595 confined participants who reported personal and contextual information, depressive symptoms and PA levels at four time points. : The changes in depressive symptoms were analyzed using a linear mixed model with cubic splines. Results showed a significant increase, with a significant rise between T1 and T2 (OR = 2.38, 95% CI = 1.83-3.10). It continued growing until T4 (OR = 2.93, 95% CI = 1.97-4.38). A negative relationship was observed between the increase in depressive symptoms and moderate-to-vigorous physical activity (MVPA) levels, with a significant slope up to 4 hours of MVPA per week (OR = 0.51, 95% CI = 0.29-0.90) that tended to increase until 16 hours per week of MVPA (OR = 0.41, 95% CI = 0.20-0.87). : Results from a partition model showed that moderate intensity of PA could be enough to prevent an increase of depressive symptoms during home isolation.