Does it matter if we exercise in the morning or at night (1)? Recent research has found that the effect of exercise may differ depending on the time of day it is performed, confirming the theory that our body’s circadian clock can affect our health.
When we exercise also tunes our internal clocks.
Physiological and neurobiological processes depend on biological rhythms in the body, which change over the course of the day. Our internal clocks affect metabolism, body temperature, blood sugar, blood pressure, appetite, heart rate, hormone levels, energy levels, and cellular processes.
Based on previous published studies, circadian rhythms of sports performances are linked closely in phase with the rhythm of core body temperature, suggesting a causal link between them. These diurnal variations are influenced by the regular training at a particular time of day. The research showed that training in the morning can improve typically poor morning performances to the same or even higher level as their normal daily peak typically observed in the late afternoon and decrease the amplitude of the diurnal rhythm. However, training in the evening hours can increase the amplitude of the daily variations of neuromuscular performances.
Benefits of Morning Exercise
Morning exercise has very different effects on metabolism than an identical workout performed later in the day. Morning exercise initiates gene programs in the muscle cells, making them more effective and better capable of metabolizing sugar and fat. Thus, morning exercise helps us burn sugar and fat throughout the day. This is especially helpful for people who are overweight or have type 2 diabetes.
Benefits of Evening Exercise
Evening exercise, on the other hand, increases whole body energy expenditure for an extended period of time. The results also show that exercise in the evening increases energy expenditure in the hours after exercise.
Based on this information we cannot say for certain which is best, exercise in the morning or exercise in the evening. There are still a lot of discrepancies and inconsistencies with regard to our internal clocks and exercise. At this point, we can only conclude that the effects of the two appear to be different. But regardless of timing, there are significant health benefits from exercising from thirty to sixty minutes each day. Paying attention to when you have the most energy may provide a clue as to what your body needs and how effective your workout will be. Until the issue of timing is better understood, for now it’s best to choose the time that is most convenient.
(1) Chtourou, Hamdi1,2; Souissi, Nizar1,3. The Effect of Training at a Specific Time of Day: A Review. Journal of Strength and Conditioning Research: July 2012 – Volume 26 – Issue 7 – p 1984-2005 doi: 10.1519/JSC.0b013e31825770a7
(2) Seo DY, Lee S, Kim N, Ko KS, Rhee BD, Park BJ, Han J. Morning and evening exercise. Integr Med Res. 2013 Dec;2(4):139-144. doi: 10.1016/j.imr.2013.10.003. Epub 2013 Oct 14. PMID: 28664065; PMCID: PMC5481716.