body clock
The timekeeper in your brain that runs on a cycle of about a day, setting when you feel sleepy and when you feel alert. Daylight, especially in the morning, keeps it in step with the clock on the wall.
Where it comes up
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01
How do I get through the day after a bad night?
Barely slept? How one short night really affects your day, what helps you get through it, and why tonight's sleep will probably be deeper.
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02
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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03
What is the body clock, and how does it decide when I'm sleepy?
How your body clock works: a clock in nearly every cell, reset each morning by light, and why some people are simply built to sleep later.
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04
How much sleep do I really need?
How many hours of sleep adults need, why it's a range rather than one number, and how to tell from your days whether you're getting enough.
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05
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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06
Is it okay to take melatonin every night?
Is melatonin safe to take every night? How the body's nighttime signal works, what it helps and which dose and timing make sense, with a word on children.
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07
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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08
Why am I wide awake at bedtime?
Wide awake at bedtime after a long day? Why the body clock pushes alertness in the evening, how naps and caffeine add to it, and what helps tonight.
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09
How do I sleep well on night shifts?
Why sleep after a night shift is short and light, and what helps: when to sleep, a nap before work, light and darkness, and guarding day sleep at home.
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10
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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11
What can I do when worry keeps me awake?
When a real worry about money, health, work or someone you love keeps you awake: why it seems bigger at night, and how to leave it until morning.
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12
How do I wind down when I’m tired but wired?
Tired but wired in the evening and can’t switch off? Why the day keeps running after you stop, and how to let it wear off without a routine to get right.
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13
Why can’t my teenager fall asleep before midnight?
Teenagers’ body clocks really do shift later. Why your teen isn’t sleepy at 10pm, what school start times do, and how to help without a nightly fight.
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14
Why does my sleep change as I get older?
Why sleep gets earlier, lighter and more broken as you get older, which changes come with age itself and which come from something else, and what still helps.
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15
What is REM sleep?
What REM sleep is, why your body can’t move while your brain is nearly awake, why it gathers toward morning, and what it may do for memory.
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16
What makes us feel sleepy?
Why sleepiness builds the longer you're awake, how the body clock puts it off, and why caffeine, naps and sleeping in work the way they do.
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17
How do I get over jet lag faster?
Why you’re wide awake at 3am after a long flight, why flying east is harder, and how to time light and dark so your body clock catches up sooner.
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18
Why do I wake up too early and can't get back to sleep?
Waking an hour or two before your alarm and lying there until it goes? Why it happens, from an early body clock to low mood, and what helps you sleep later.
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19
Why do my legs feel restless at night?
Restless legs at night: what the creeping urge to move is, why it comes in the evening, how iron and some medicines feed it and what helps.
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20
What makes a bedroom good for sleep?
What makes a bedroom good for sleep: why cool, dark and steady sound matter, what's mostly marketing and what helps if you share a bed or sleep by day.
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21
Why are some nights better than others?
Why you sleep well one night and badly the next: how your day, wake time, light and hours awake shape tonight's sleep, and why some variation is normal.