Identifying causes of healthy behaviors is important for harnessing health benefits. A growing body of experience sampling research suggests that positive emotion may drive these behaviors. However, it is not known how long elevations in positive emotion facilitate these behaviors in daily life. The present study tested how time between signals moderates the association between within-person positive affect and healthy behaviors. A sample of 197 college students completed a 10-day experience sampling diary, with 5 signals a day, measuring affect and healthy behaviors. We replicated results from Nylocks and colleagues (2018) finding that within-person positive affect predicted engagement in healthy behaviors; however, this association was only significant within the same day, and not across days (i.e. overnight). Taken together, these findings highlight the importance of considering positive affect, rather than negative affect in patients with psychopathology, to improve behavioral interventions targeted to increase engagement in healthy behaviors.