Virtually every organism on the planet — from bacteria to humans — has a circadian clock, a biological timing mechanism that oscillates with a period of about 24 hours and is coordinated with the cycle of day and night. And while it runs independent of external cues, it is influenced by sunlight, temperature and food availability. This internal ‘body clock’ guides the best time for many activities. The observation of this process in humans was mentioned in Chinese medical texts dating back to around the 13th century. Referred to as the circadian rhythm – from the Latin ‘circa’ meaning “around” and diem meaning ‘day’, this timekeeper guides activities of the body including the best times to eat and sleep.
Almost every function of the body oscillates during the day according to this clock. For example, body temperature is regulated in part by this internal clock. The body’s temperature is lowest around 5am, just before waking in the morning, and highest in the late afternoon. This may have some bearing on heart attacks, which are most common in the morning hours. There are indications that the circadian clock also helps to regulate metabolism. When altered or hindered, that biological clock can wreak havoc in the body. For example, people can experience fatigue and dizziness, known as jet lag, when crossing time zones. Others suffer from depression when living in places with minimal daylight/sunlight such as Alaska.
This internal clock seems to also impact a person’s chronotype; that is whether the individual is a morning person, a night dweller or somewhere in between. A person’s chronotype affects their productivity at work. How so? While a person’s chronotype may not seem like an important employment variable, it has a profound impact on every employee’s creativity, attitude, problem solving skills, and ability to socialize. And those variables have a direct impact on the bottom line of every business. It helps to understand how a person’s chronotype should fit with their work hours and demands.
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