Every human body has an internal clock, and the body’s routine is dependent on that internal clock. This internal clock tells the body when to sleep, when to wake up, when to eat, etc.

A recent study suggests that this internal clock lies within the control of the body and could be altered as per one’s liking. The internal clock could be modified by performing the exercise, or specifically with the movement of the muscles. However, the time of the exercise plays its part too.

Even though the master clock is located up in the brain, each muscle has its own clock. Each clock present in the muscle tissue has its circadian rhythm. In this circadian rhythm, hormones are released at fixed intervals during the day. The body responds to these hormones and carries out a function which is then known as a routine.

An experiment was conducted on 30 female mice and they were put to exercise during their rest phases. Note that mice are nocturnal animals and their rest phase begins during the day as opposed the humans. They were put to exercise in the middle of their rest phase, in the middle of their active phase, and during the end of their rest phase. Results were noted down under each scenario.

Phase delays and advancements were seen when mice were put to exercise during the end of their rest phase and in the middle of their rest phase respectively. However, no change was seen when they exercised in the middle of their active phase.

Just to be extra sure that it was the muscle movement that was causing changes in the internal clock, scientists electrically stimulated the muscles as well and similar results were observed.

The research only shows that exercise can alter the body clocks present in the tissue peripherals. Its effect on the master clock that is present in the brain is still unknown.

This research could prove to be beneficial to the night shift workers who can modify their routine and internal clocks by exercising at certain times during the day. This could even be used to cure body clock disorders that happen in heart patients.

Another research was conducted in 2019 that shows that people felt active and inactive during a day the depending upon the time when they exercised. If they exercised early in the morning they felt more active earlier during the day, as opposed to those who chose to exercise later in the evening.

The study, “Time of day dependent effects of contractile activity on the phase of the skeletal muscle clock”, was authored by Denise Kemler, Christopher A. Wolff, and Karyn A. Esser