Circadian Rhythm

The circadian rhythm is an internal timekeeping system driven by a cluster of neurons called the suprachiasmatic nucleus in the brain's hypothalamus. This biological clock responds primarily to light and darkness, signaling the body when to produce sleep hormones like melatonin and wake-promoting hormones like cortisol.

Disrupting circadian rhythms through shift work, jet lag, irregular sleep schedules, or excessive evening screen exposure has been linked to numerous health problems including obesity, type 2 diabetes, cardiovascular disease, depression, and impaired immune function. Research has shown that even a few days of circadian misalignment can reduce insulin sensitivity and increase inflammatory markers.

Optimizing circadian health involves maintaining consistent sleep and wake times, getting bright light exposure in the morning, avoiding blue light from screens in the evening, eating meals at regular times, and keeping the sleeping environment cool and dark. The emerging field of chronobiology has shown that timing medications, exercise, and meals according to circadian rhythms can significantly improve their effectiveness.