sleep cycle
One round of the stages of sleep, from light sleep down to deep sleep and on to dreaming sleep. Each lasts about ninety minutes on average, though the length varies, and a night holds four to six of them.
Where it comes up
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01
Are naps good for you?
Are naps good or bad for you? How long and when to nap, why a long nap can leave you groggy, and how a nap changes the night ahead.
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02
Why do I keep waking up at 3am?
Waking at 3am and can't get back to sleep? Why it happens in the second half of the night, why it feels so bleak, and one small thing to try now.
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03
Why am I still tired after a full night’s sleep?
Slept seven or eight hours and still woke up exhausted? Why mornings feel so slow, from sleep inertia to body-clock timing, and when it's worth a doctor.
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04
What happens while we sleep?
What happens while you sleep: light, deep and REM sleep, how the cycles repeat through the night, and why brief wakings are a normal part of it.
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05
How can I help my child sleep?
Why children wake in the night and call for you, how much sleep school-age kids need, and ways to ease bedtime battles, fears and night wakings.
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06
How much should my newborn sleep, and how do I keep them safe?
How much newborns sleep, why they wake every few hours and mix up day and night, when nights lengthen and how to put your baby down safely.