The internal clock in living beings that regulates sleeping and waking patterns -- usually called the circadian clock -- has often befuddled scientists due to its mysterious time delays. Molecular interactions that regulate the circadian clock happen within milliseconds, yet the body clock resets about every 24 hours.

Our body’s production of urine follows a circadian rhythm. During the day, we experience greater urinary frequency; at night, urine production declines, enabling us to get uninterrupted sleep. The regulation of urine excretion during nighttime hours is influenced by many factors, including hormones, blood flow (hemodynamics), and sleep-related factors.