What "good sleep" means

Enough hours, falling asleep without a fight, few wake-ups, regular times, and feeling alert in the day.

• Evidence: Strong
• Low effort
• Free
• Works: 1 week

Why it matters

The American Academy of Sleep Medicine and the Sleep Research Society recommend at least 7 hours a night for adults. Regularly sleeping less is linked to weight gain, diabetes, high blood pressure, heart disease, depression and a higher risk of death [1]. More than 9 hours can be fine for young adults, people catching up on lost sleep, or people who are ill [1].

Hours aren’t everything. Researchers describe “sleep health” as several dimensions, measured both by how you feel and by recordings [6]. For this site, that comes down to five things you can check: duration, how fast you fall asleep, how much you wake, regularity, and how alert you feel.

How to do it

Check your own sleep against these markers. The first four come from a National Sleep Foundation panel that reviewed 277 studies [2].

1. Total sleep: 7 hours or more on most nights [1]. Average a whole week, not one night.
2. Falling asleep: 30 minutes or less [2].
3. Waking: no more than one wake-up longer than 5 minutes, and 20 minutes or less awake in total after you first fall asleep [2].
4. Sleep efficiency: 85% or more. That’s time asleep divided by time in bed. 7 hours asleep in 8 hours in bed is 88% [2].
5. Regular times. Going to sleep and waking at similar times each day is important for health, safety and performance [3]. There’s no agreed cutoff; closer is better.
6. Daytime alertness. Can you get through the afternoon without fighting sleep? That’s the result all the other numbers are meant to predict.

Common mistakes

• Chasing a deep-sleep or REM percentage. The NSF panel reached little or no agreement that sleep stage amounts are a sign of good sleep quality [2]. App targets such as Oura’s “15–20% deep sleep” and “about 1.5 hours of REM” are the company’s guidance [7], not clinical standards.
• Comparing yourself with a 25-year-old. In healthy adults, total sleep, sleep efficiency and the share of deep and REM sleep all fall with age, and time to fall asleep and time awake at night rise [5]. Compare with your own past weeks.
• Judging by one bad night. Everyone has them. Look at weekly averages.
• Staying in bed longer to get more sleep. If the extra time is spent awake, your efficiency drops and the bed starts to feel like a place to lie awake.

Effect on your sleep score

The markers above map onto what wearables report:

• Duration is the biggest single part of Apple’s Sleep Score: 50 of 100 points. Bedtime consistency is 30 points, and interruptions are 20 [8].
• Time to fall asleep is Oura’s Latency contributor. Oura calls 15–20 minutes ideal [7], which is stricter than the NSF’s 30 minutes [2].
• Efficiency is an Oura contributor too; Oura uses the same 85% line [7].

How confident: the definitions match well. How accurately each device measures them is a separate question, covered in the Wearables section.

Evidence

The 7-hour recommendation and the sleep quality markers both come from expert panels that used formal voting methods after reviewing the research [1][2]. That’s why this page is rated Strong.

Regularity has a consensus statement behind it [3], plus large observational data. In 60,977 UK Biobank participants who wore activity trackers, the most regular sleepers had a 20–48% lower risk of dying during follow-up than the least regular [4]. That study shows a link, not that regularity causes the difference, and its participants averaged 63 years old.

General information for healthy adults, not medical advice. If you have a sleep problem that lasts, read when to see a doctor. Sources checked 4 October 2026. Spot a mistake? Tell us.