Eight hours not enough: a sleep doctor explains how routine matters more than sleep duration

Eight hours in bed isn’t always enough if your sleep cycles are repeatedly interrupted. A sleep doctor says sleep quality and regularity matter more than total hours: most adults cycle through 4–6 ~90-minute stages nightly, so a consistent bedtime and wake time, plus a cool bedroom (about 65–68°F), limited caffeine after lunch, and short naps can improve how rested you feel in the morning.