This study examines the short-term recovery benefits of weekend physical activity on reduced negative affective state (NA) on Monday morning, using a weekly diary method from 70 employees across four weekends (repeated pre- and post-weekend measures). The first hypothesis tests the within-person relationship between weekend physical activity and post-weekend NA. The results of multilevel path analysis show that the main effect of weekend physical activity on reduced Monday NA is not significant. In addition, the study tests weekend recovery experiences (i.e., psychological detachment, relaxation, mastery, and control) and sleep hours as possible moderators. The findings support the moderating effects of psychological detachment and sleep hours. Specifically, weekend physical activity is related to lower Monday NA only if workers achieve high psychological detachment from work during the weekend. If not, their weekend physical activity is associated with higher NA. Also, the benefit of weekend physical activity occurs only when workers sleep longer on the weekend nights. The findings suggest that physical activity has important boundary conditions-psychological detachment and sleep duration-that influence its recovery effects on NA. The complex relationship between exercise and recovery is discussed, along with the implications of the findings for future research.