The present study aimed to advance insight in the role of leisure time physical activity (LTPA) in the recovery process, by focusing on the strenuousness of LTPA. It was proposed that-compared with less strenuous LTPA-more strenuous LTPA would show stronger positive relationships with recovery through higher levels of mental disengagement from stressors resulting from more strenuous LTPA. This hypothesis was examined in two studies, in which participants' positive and negative affective states were included as indicators of recovery. Study 1 was a 10-day daily diary study (3 measurements daily) among 74 employees. Each day, participants reported the time they had spent on mild, moderate, and strenuous LTPA. Multilevel path analysis showed that only strenuous LTPA was related to beneficial changes in the two indicators of recovery before bedtime and in the next morning through its positive relationship with psychological detachment from work. Study 2 was an experiment with two between-participants conditions, in which-after a stress-inducing task-44 participants engaged in either (a) a 20-min moderate intensity cycling task, or (b) a 20-min high intensity cycling task. Results showed that high intensity exercise was indirectly related to higher recovery as indicated by a lower level of participants' negative affective state, through lower levels of rumination about the stress-inducing task in this condition. The results of these two studies indicate that to fully savor LTPA's beneficial effects through mental disengagement from stressors, it is best conducted with a high level of strenuousness. (PsycINFO Database Record (c) 2019 APA, all rights reserved).