Circadian Rhythms and the Biological Clock: Our Body’s Internal Timekeepers

What Are Circadian Rhythms and the Biological Clock?

Circadian rhythms are biological rhythms that determine our body’s internal clock. They help regulate our daily life, including our sleep-wake cycle, body temperature, metabolism, and other physiological processes. These rhythms repeat approximately every 24 hours independently of external environmental factors.

How Does the Biological Clock Work?

Our biological clock is controlled by specialized groups of cells in a region called the hypothalamus. These cells synchronize with signals from light-sensing cells in the eyes that detect environmental light levels. When more light is detected during the day, the body becomes more awake and active, whereas when less light is detected at night, the body prepares for sleep.

The Role of Melatonin Hormone

Melatonin is a crucial hormone that regulates the body’s internal clock. It is secreted at night and controls the sleep cycle. Melatonin secretion is regulated based on environmental light levels. The use of red-colored lights or blue light filters on screens can positively affect melatonin secretion and sleep quality.

Chronobiology and Its Applications

Understanding circadian rhythms and the biological clock has led to the development of a field called chronobiology. Chronobiology studies the changes in our body over time and uses this knowledge to cope with conditions such as sleep disorders, jet lag, and shift work.


This information is based on research in the fields of biology, physiology, and medicine. More information on biological clocks and circadian rhythms can be found in scientific articles and books. Publications by researchers focusing on biological clocks and circadian rhythms can provide in-depth knowledge on these topics.

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