Question 1

How many hours of sleep do adults need?

Accepted Answer

CDC recommends 7–9 hours for adults 18–64. Teenagers 8–10 hours, children 9–12 hours, adults 65+ need 7–8 hours.

Question 2

What is a sleep cycle?

Accepted Answer

Sleep cycles last ~90 minutes, including light sleep, deep sleep, and REM. Adults complete 4–6 cycles per night. Waking at cycle end leaves you more refreshed.

Question 3

What happens without enough sleep?

Accepted Answer

Chronic deprivation increases risk of obesity, type 2 diabetes, heart disease, depression, and impaired cognition. One bad night impairs reaction time like mild intoxication.

Question 4

How to improve sleep quality?

Accepted Answer

Consistent schedule, cool dark room (65–68°F/18–20°C), no screens 1 hour before bed, no caffeine after 2pm, regular exercise (not within 3 hours of bedtime).

Question 5

What is the best bedtime?

Accepted Answer

Count back in 90-minute intervals from wake time. For 6:30am wake: optimal bedtimes are 9:30pm, 11:00pm, 12:30am, 2:00am, 3:30am, or 5:00am.

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