False. The 7-9 hour range is the adult average; individual needs vary by 1-2 hours either side, and what matters is how you function, not the round number.

False. Loud, habitual snoring is the most common visible sign of obstructive sleep apnea, which raises risk of heart disease, stroke, and daytime accidents. Worth screening.

False. This was an old wives' tale based on the fact that early-night sleep has more deep sleep. The hours themselves aren't special — your sleep architecture matters, not the clock.

False. Alcohol speeds onset but fragments the second half of the night — less REM, more wake-ups. Even one drink measurably degrades sleep quality.

False. Catch-up sleep restores some function but not all. Metabolic and inflammatory markers recover slowly, and the timing shift itself creates social jet lag that haunts Monday.

False. The need stays close to 7-8 hours; what changes is the ability to consolidate it. Older adults often get less because they wake more often, not because they need less.

True. Naps under 25 minutes stay in light sleep, so you wake up without sleep inertia. Cross 30 minutes and you risk dropping into deep sleep, which causes the foggy feeling.

True. Blue-rich light in the hour before bed measurably shifts melatonin onset later — meaningful for sleep timing if your phone is the last thing you see.

False. After ~20 minutes awake, get up, dim the lights, and do something boring. Lying frustrated in bed trains your brain to associate the bed with wakefulness.

False. The 9-minute snooze cycles are too short to enter restorative sleep, and the repeated interruptions worsen sleep inertia. One firm alarm is better.

False. Falling asleep requires your core body temperature to drop. A cool room (16-19°C / 60-67°F) is the single most-studied environmental factor for sleep onset.

False. Most people dream every cycle; remembering them just means you woke up during or right after REM. It's neutral — not a sign of bad sleep on its own.