Mechanisms of Action
Circadian Rhythm
The body's internal 24-hour clock regulating sleep-wake cycles and physiological processes.
The circadian rhythm is an endogenous ~24-hour cycle driven by the suprachiasmatic nucleus (SCN) of the hypothalamus, synchronized to external light-dark cues. It regulates sleep-wake timing, hormone secretion (melatonin, cortisol, growth hormone), body temperature, and metabolism. Circadian disruption (shift work, jet lag, irregular schedules) is associated with sleep disorders, metabolic dysfunction, and impaired immune function. Melatonin supplementation, light exposure timing, and sleep hygiene are primary interventions for circadian rhythm optimization.