Most people generally decide whether to exercise in the morning or evening, or possibly a combination of the two simply due to time availablility or individual preference. Some people swear by the 6am workouts that gets them pumped for the rest of the day, others wouldn’t dare break a sweat before lunch, but is there a ‘best’ time of day to exercise?

Have you ever considered the possible benefits or negatives of which time of day you decide to exercise? 

Several studies have focused on this exact question and looked at varying physiological processes to see the change to morning and evening exercise. One study compared the differences in a maximal exertion treadmill test on untrained individuals randomly performed once in the morning and once in the evening. Recording heart rate, oxygen consumption, respiratory exchange ratio, rate of perceived exertion and total exercise time, they found no significant difference in performance during maximal exercise. Due to variations in body temperature, a longer warm up may be required in morning training due to a slower increase in body temperature, which may have an effect on ventilation responses and rating of perceived exertion.

Exercising in the morning has been linked to a better night’s sleep. Exercising just before bed can affect sleep due to increased levels of endorphin’s and serotonin. If you have trouble getting to sleep at night, it’s best to make sure you don’t exercise within two hours of going to bed.

One study focused on the effect morning and evening exercise had on the hormones; growth hormone (important for human development) and cortisol (helps the body manage stress). Previous research has shown that these two hormones response to exercise is dependent on other factors, such as: workload, mode, duration, anaerobic vs. aerobic, diet and fitness level. When such factors are controlled, it was found that time of day does not alter growth hormone response to exercise; however, peak cortisol concentrations in response to exercise were found in the morning.

Another study focused on the psychological responses to exercise and found no significant changes in anxiety, depression, anger or mood following high intensity exercise in the morning or evening, concluding that mood and anxiety responses to exercises are similar whether exercise is performed in the morning or evening

So what can we take from all of this? While some studies have shown possible benefits to exercising either in the morning or evening the vast majority show no significant change and agree that it really doesn’t matter what time of day you exercise – the most important thing is to pick a time of day that works best for you, because after all exercising any time of day is better than not exercising at all.