How the Circadian Rhythm Affects the Brain

Time is a man-made phenomenon, but the human body runs on a sort of clock, which is located in the hypothalamus region of the brain. Studies of this phenomenon have shown that a person tends to feel more mentally alert at 9:00 a.m. and 9:00 p.m. each day, while their physical strength seems to peak at 11:00 a.m. and 7:00 p.m. respectively. This concept is known as the circadian rhythm, which describes how the body reacts to light and patterns of sleep and wakefulness in reaction to hormonal fluctuations. Not all of the body’s rhythms are affected by light; certain chemicals in the body also regulate various body systems.

Melatonin, a natural hormone, controls sleep patterns in both people and animals. It has been suggested that the lower production of the hormone melatonin, normally secreted during regular sleep, can affect organs other than the brain and can lead to cardiovascular disease.

A person’s state of mind is directly affected by these 24-hour a day hormonal variations. But when the patterns are interrupted, people can suffer from fatigue, anxiety and other ill-effects. A common occurrence associated with a disruption in the circadian rhythm is jet lag. Travelers who cross multiple time zones, usually on an international flight, are unprepared physically to cope with the light and time difference upon arriving at their destination.  Sleep patterns can be thrown off for up to a week afterwards, causing fatigue and disorientation.

This disruption can be a major problem for some professionals, such as commercial airline pilots. The United States National Transportation Safety Board has determined that fatigue caused by altered circadian rhythm cycles has led to a number of airline accidents. Disruption of the circadian rhythm can even cause serious disorders including bipolar disorder and even depression.

Recognizing the importance of circadian rhythms in body function, certain lifestyle habits can enhance regularity and facilitate the healthy secretion of melatonin. These habits include waking up to sunlight; which increases energy; waking and sleeping at consistent times; getting work done early in the day when the mind is at its peak efficiency; eating whole grain, fruits and vegetables; and steering clear of stimulants and other harsh drugs that may interfere with hormone production.

This post is brought to you by Argosy University. Drawing upon our more than 30-year history of granting degrees in professional psychology, Argosy University has developed a curriculum that focuses on interpersonal skills and practical experience alongside academic learning. Because getting a degree is one thing. Succeeding, quite another.