When people are asked if they are good sleepers, they usually focus on how many hours they sleep. They may say, “I know I should get 7 or 8 hours of sleep, but I can sleep only 6.” However, when it comes to sleep, quality is as important as quantity.
What is good-quality sleep? Measuring sleep quality can be difficult, since it’s a subjective experience, and we are poor self-observers while sleeping. But nowadays some people go to sleep clinics to evaluate their sleep, and millions use a variety of sleep-tracking devices and apps.
In part to help people assess the data they may get from such devices, a panel of experts assembled by the National Sleep Foundation recently published its key indicators of sleep quality in the journal Sleep Health. The panel included not only experts on sleep, but also neurology, geriatrics, biology, and human development. Based on their analysis of 277 studies, they came up with these four “objective components” of good-quality sleep:
- Falling asleep within 30 minutes of going to bed.
- Sleeping at least 85 percent of the time spent in bed.
- Waking no more than once per night for 5 minutes or longer.
- Being awake for less than a total of 20 minutes after initially falling asleep. That is, it’s okay to wake up briefly, say, 5 times. But only one of these wake-ups should be longer than 5 minutes (see previous bullet).
For people over 65, the criteria are relaxed somewhat, since sleep patterns change with age. Thus, if they take longer to fall asleep (up to 60 minutes) and wake up more often (totaling up to 30 minutes after initially falling asleep), that can still be considered good-quality sleep.
What about various sleep stages, such as REM (rapid eye movement) or slow wave sleep—how much of your night should be spent in each of them? The expert panel could reach no consensus about the optimal amounts of the stages.