Circadian rhythm is the body’s internal 24-hour clock that regulates sleep, alertness, hormone release, and other biological processes. It is influenced by external cues like light and darkness, but also runs independently.
For example, most people naturally feel more alert in the morning and sleepier at night due to circadian rhythms. Disruptions—such as jet lag, night shift work, or excessive screen time—can impact mood, concentration, and overall health.
Circadian rhythm is controlled by the brain’s suprachiasmatic nucleus (SCN), which synchronises body systems to the day-night cycle. Maintaining a consistent sleep schedule and regulating light exposure can help establish a healthy sleep rhythm.