When to Work Out: Understanding the Impact of Exercise Timing
We all know exercise is good for us. For the most part, consistent exercise will elicit a positive change: increase muscle and bone strength; decrease the risk of developing a chronic disease; increase cognitive ability and memory; maintain or increase functional capacity for activities of daily living. The list goes on; however, recent research suggests that the time of day when one engages in physical activity can influence performance, health outcomes, and even psychological well-being.
Performance Variations Throughout the Day
Human physiology operates on a circadian rhythm, a roughly 24-hour cycle influencing various bodily functions, including those related to physical performance. Studies have shown that muscular strength and short-term anaerobic performance tend to peak in the late afternoon or early evening. A systematic review and meta-analysis by Chtourou and Souissi (2012) found that short-term high-intensity performance is generally higher in the evening compared to the morning, likely due to fluctuations in body temperature and hormone levels. Muscle hypertrophy and strength were also found to have greater improvements with evening compared to morning exercise (Grgic et al., 2019).
Endurance performance exhibits a similar time-of-day effect with a preference for evening exercise, as shown in the research conducted by Kang and colleagues (2023). However, the effect was not as pronounced compared to anaerobic performance and their review also suggested that individual factors such as habitual training time and chronotype may still play significant roles.
Individual Differences
An individual’s chronotype—their inherent predisposition toward being a “morning person” or “evening person”—can significantly influence how exercise timing affects performance. Facer-Childs et al. (2018) demonstrated that early chronotypes performed better in the morning, whereas late chronotypes exhibited superior performance in the evening. This suggests that aligning exercise schedules with one’s chronotype may optimize performance and reduce perceived exertion. Most people with lived experience will know intuitively if they are more of a “morning” or “evening” person and can adjust their exercise timing where able.
Metabolic and Cardiovascular Implications
The timing of exercise also impacts metabolic health and cardiovascular risk factors. A study by Savikj and Zierath (2020) revealed that evening exercise improved glucose tolerance and lipid profiles more effectively than morning sessions in individuals with type 2 diabetes. This exercise timing effect was also observed with insulin resistance, with a reduction of up to 25% observed in participants who performed moderate to vigorous activity in the evening compared to the morning (van der Velde et al., 2023). These findings imply that for certain populations, scheduling exercise later in the day might confer additional metabolic benefits.
Moreover, research has found that evening exercise led to more significant reductions in blood pressure, in individuals with hypertension, compared to morning workouts (Brito et al., 2019). These results suggest that for individuals managing hypertension, exercise completed in the evening could be more advantageous.
Psychological and Cognitive Effects
Exercise timing can also influence mood and cognitive function. An investigation by Schmidt et al. (2015) indicated that evening exercise enhanced working memory performance in evening-type individuals, whereas morning exercise benefited morning types. This underscores the importance of considering individual differences when scheduling workouts to maximize cognitive benefits.
Practical Considerations and Recommendations
At the end of the day (*hold for laughter*), the best time to exercise is when it is going to work for you. While the timing of exercise can influence various aspects of performance, metabolic health, and psychological well-being, engaging in regular physical activity, regardless of the time of day, is crucial for overall health. Individuals should consider their chronotype and health goals when determining the best time to exercise, while accepting that the most important factor remains the commitment to regular exercise, irrespective of the time of day.
References
Chtourou, H., & Souissi, N. (2012). The effect of training at a specific time of day: a review. Journal of Strength and Conditioning Research, 30(3), 682–690.
Brito, L. C., Peçanha, T., Fecchio, R. Y., Rezende, R. A., Sousa, P., DA Silva-Júnior, N., Abreu, A., Silva, G., Mion-Junior, D., Halliwill, J. R., & Forjaz, C. L. M. (2019). Morning versus Evening Aerobic Training Effects on Blood Pressure in Treated Hypertension. Medicine and science in sports and exercise, 51(4), 653–662.
Facer-Childs, E., Boiling, S., & Balanos, G. M. (2018). The effects of time of day and chronotype on cognitive and physical performance in healthy volunteers. Sports Medicine – Open, 4(1), 47.
Grgic, J., Lazinica, B., Garofolini, A., Schoenfeld, B. J., Saner, N. J., & Mikulic, P. (2019). The effects of time of day-specific resistance training on adaptations in skeletal muscle hypertrophy and muscle strength: A systematic review and meta-analysis. Chronobiology international, 36(4), 449–460.
Kang, J., Ratamess, N. A., Faigenbaum, A. D., Bush, J. A., Finnerty, C., DiFiore, M., Garcia, A., & Beller, N. (2023). Time-of-Day Effects of Exercise on Cardiorespiratory Responses and Endurance Performance-A Systematic Review and Meta-Analysis. Journal of strength and conditioning research, 37(10), 2080–2090.
Savikj, M., & Zierath, J. R. (2020). Train like an athlete: applying exercise interventions to manage type 2 diabetes. Diabetologia, 63(8), 1491–1499.
Schmidt, C., Collette, F., Cajochen, C., & Peigneux, P. (2015). Pushing the limits: chronotype and time of day modulate working memory-dependent cerebral activity. Frontiers in Neurology, 6, 199.
van der Velde, J. H. P. M., Boone, S. C., Winters-van Eekelen, E., Hesselink, M. K. C., Schrauwen-Hinderling, V. B., Schrauwen, P., Lamb, H. J., Rosendaal, F. R., & de Mutsert, R. (2023). Timing of physical activity in relation to liver fat content and insulin resistance. Diabetologia, 66(3), 461–471
