Every living human is controlled by an internal “clock” which drives our circadian rhythm – the natural internal process that regulates our sleep-wake cycle during a 24-hour period. This internal clock controls most of our body processes over this period, including our sleep cycle, digestion, metabolism, appetite and immunity.
External light levels, eating times and physical activity all act to keep the body clock synchronised to the external environment. Every cell in our body also has its own clock, which helps keep these processes working so seamlessly. For example, clocks in individual tissues, such as the liver, work to ensure timely supply of energy to the rest of the body.
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