Should you run on an empty stomach in the morning, exercise during your lunch break, or workout after work? Are certain hours more effective for burning calories or building muscles?
Our natural circadian rhythm, which regulates many functions of the body (release of hormones, muscle metabolism…), has a great influence on the effects of our activity. Numerous contradictory studies have been published on the most favorable times for sports activities. This is what we can carefully conclude from them.
Exercise in the morning
When you wake up, your body needs time to recover. You should, therefore, avoid physical activity that puts too much stress on your heart and joints, such as jogging or bodybuilding. However, some scientists believe that morning exercise can help you get a good night’s sleep and lower your blood pressure during the day. A study by the University of Copenhagen on rats shows that morning exercise has a more beneficial effect on sugar and fat metabolism, which means muscles use resources more efficiently.
Does running on an empty stomach means you can lose more weight?
The body has no carbohydrates available, so you have to rely on your fat reserves, but these are more difficult for the muscles to access which causes them to consume themselves. As a result, you are more likely to get hurt or have an accident. Not to mention the danger of hypoglycemia.
Sports during lunch break
Many employees use their lunch breaks to practice their favorite sport. Multi-person training can be a good source of motivation. On the other hand, it is not advisable to start an aerobics session immediately after eating as it can interfere with digestion,
Working out in the afternoon
The human body is programmed to think in the morning, be physically active in the afternoon, and relax in the evening. According to experts, the best time of day to work out would, therefore, be between 3 and 7 pm: digestion is complete, body temperature is at its maximum and blood sugar levels are more or less constant. Several studies have shown that muscle strength peaks at around 5 pm and anaerobic strength increases significantly between 2 pm and 6 pm compared to 9 am; 5 pm is also the time when the body burns calories more quickly.
Exercising at night
Doing an intense workout before bedtime can delay sleep by increasing body temperature and restarting the production of adrenaline and cortisol, which have a stimulatory effect. For this reason, it is generally recommended to stop all sports activities at least two hours before going to bed. But even here there are conflicting opinions: A 2019 study says that late exercise has no effect on the quality of sleep and that it reduces the levels of ghrelin, a hormone that stimulates the appetite. Playing a sport at night would also prolong overall energy expenditure for a longer period after the session, according to researchers at Copenhagen University.
Conclusion: When is it best to exercise?
It really depends on your personal Circadian Rhythm. According to a study by the University of Birmingham, there is a 26% difference in performance between people who wake up early and those that sleep late. “Athletes who wake up early will perform best in the middle of the day, while athletes who get up late reach their peak performance at night around 8 pm,” says Roland Brandstaetter, one of the authors. Then there are the practical aspects: Who is really free in the middle of the afternoon to do sport, or is motivated enough to go running in the cold at 6 am? The most important thing is regularity, so first, choose the time that suits you best.