Sleep does more than fight fatigue. Doctors explain how a chronic lack of sleep weakens immunity, affects vaccine response, ...

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How does your brain know when it's time to sleep? There are two main factors: Hours Awake. The longer you've been awake, the stronger your drive for sleep. Circadian Rhythm. Your body operates on a ...

From babies who cry through the night to teens who sleep all morning to older adults who just can’t seem to catch any z’s, sleep patterns and the amount of sleep you need change throughout our lives.