It depends on one key factor. According to a BBC article, recent research has shown that there is an ideal time to do physical activities. In the Olympic Games of 2004, 2008, 2012, and 2016, 144 swimmers who won medals performed better when they competed in the late afternoon. Around 5:12 PM, to be exact. This finding is part of a growing body of evidence that suggests that the time of day influences athletic performance. The effect is not only seen in Olympic champions: amateur cyclists in time trials are also faster in the late afternoon. Resistance exercises are also very sensitive to timing, with performance usually peaking between 4:00 PM and 8:00 PM.
What is the reason behind this? The key role of the circadian rhythm, also known as the “internal clock of the human body,” explains this phenomenon: a central clock located in the hypothalamus responds to light exposure through signals from the optic nerve. Then, the suprachiasmatic nucleus sends signals to peripheral clocks, other organs, muscle tissues, and fat tissues, allowing the body to stay in sync. Juleen Zierath, an exercise physiologist at the Karolinska Institute in Sweden, has investigated the connections between the circadian rhythm and sports practice. With her team, she has found that the benefits of physical exercise can be enhanced depending on the time of day it is done. For instance, women had better performance when they exercised in the evening than when they did the same workout at another time of day. Therefore, doing a physical activity at a certain time could optimize the benefits of this activity on health, especially for people with metabolic diseases such as type 2 diabetes or obesity. “Everyone agrees that it is good to exercise, no matter the time of day, but we may be able to fine-tune the metabolic outcomes of exercise depending on when we do it,” says Juleen Zierath.
You can also “reset” your internal clock if you realize that your circadian rhythm is not aligned with your preferences. This is shown by the latest study from the research group led by Karyn Esser, which focused on mice. At first, performance was better in mice doing exercises in the morning than in mice doing exercises in the afternoon. After six weeks of training, both groups had the same endurance level. The researchers speculate that if a similar effect happened in humans, an athlete could “reset” their internal clock through proper training, simply by doing it consistently at the same time of day. Remember that most scientists agree that doing sports is beneficial, regardless of the time of day. But if you find a time that works better for you than another and stick to it, the results will be quicker and more beneficial – both for your health and athletic performance.
