Does The Time-Of-Day Of Exercise Influence The Total Volume Of Exercise? A Cross-Sectional Analysis Of Objectively Monitored Physical Activity Among Active Individuals

Background: To improve compliance and adherence to exercise, the concept of temporal consistency has been proposed. Before- and after-work are periods when most working adults may reasonably incorporate exercise into their schedule. However, it is unknown if there is an association between the time-of-day that exercise is performed and overall physical activity levels. Methods: Activity was assessed over 1 week in a sample of 69 active adults (n = 41 females; mean age = 34.9 [12.3] y). At the end of the study, participants completed an interviewer-assisted questionnaire detailing their motivation to exercise and their exercise time-of-day preferences. Results: Participants were classified as "temporally consistent" (n = 37) or "temporally inconsistent" (n = 32) exercisers based on their accelerometry data. The "temporally consistent" group was further analyzed to compare exercise volume between "morning-exercisers" (n = 16) and "evening-exercisers" (n = 21). "Morning-exercisers" performed a greater volume of exercise than "evening-exercisers" (419 [178] vs 330 [233] min by self-report; 368 [224] vs 325 [156] min actigraph-derived moderate to vigorous physical activity, respectively). Conclusions: Our findings suggest that active individuals use a mixture of temporal patterns to meet PA guidelines. Time-of-day of exercise should be reported in intervention studies so the relationship between exercise time-of-day, exercise behavior, and associated outcomes can be better understood.