
Image: iStock. By Michele Lo, Victoria University and David Kennaway.
Most people are aware of the importance of being active and exercising daily. Unfortunately, due to busy schedules, most people are forced to exercise around other numerous commitments. However, the timing of exercise can have profound effects on performance.
All the functions and systems of the human body are moderated by a pattern called circadian rhythms (from Latin circa dies about a day). As the name suggests, these rhythms are a biological phenomena with a periodic oscillation of 24.2 hours on average. Examples of these rhythms include our body temperature, sleep/wake cycles, and the production of hormones. Human and animal lives are synchronized with the solar day and the cyclic alternations of light and darkness.
When the eyes are exposed to light, a signal reaches light/darkness receptors in the brain called zeitgebers (German for “time givers”). This portion of our brain, the suprachiasmatic nucleus, also often referred to as the “master biological clock”, is the head of a complex hierarchical system that controls how the rhythms of our body are synchronized. (Watch: Paper Tiger show you boxilates. Post continues after video.)
When to exercise
These rhythms are also related to many aspects of exercise, although their influence on athletic performance is still a matter of debate. Some argue the performance of professional athletes might be influenced by the scheduled time of a competition. However, performance is a complex process involving many different factors and the influence of circadian rhythms on the outcomes of athletes is still uncertain.
The time window of performing physical activity is broad and can change according to individual differences. In particular, people can be assigned to two broad groups: larks (people who go to bed early and rise early) and owls (people who go to bed late and rise late).
