A good night's sleep is about way more than just clocking seven to nine hours in bed each night. And now, experts in sleep medicine and other health care fields have issued new metrics that spell out exactly what high-quality slumber means.
The National Sleep Foundation, a nonprofit advocacy group, for the first time defined key indicators of good sleep quality in a recent report:
Being asleep for at least 85 percent of the time you spend in bed;
Taking 30 minutes or less to fall asleep (or up to 60 minutes if you're 65 or older);
Not waking up more than once per night for more than five minutes (or twice a night for five minutes for those 65 or older); and
Spending less than 20 minutes total awake after initially falling asleep.
These new metrics are based on the findings from 277 peer-reviewed sleep studies. An expert panel of sleep-medicine specialists and members of other health organizations (including the American Academy of Neurology, the Society for Research of Human Development and the Society for Women's Health Research) analyzed those studies and agreed on the final version. The sleep-quality indicators are separate from the National Sleep Foundation's recommendations for sleep durations for various age groups, released in 2015.
The new metrics are meant to help people better understand what good sleep health looks like overall, David Cloud, chief executive officer of the National Sleep Foundation, told The Huffington Post in an email.
"Now more than ever people are using devices [that] track their sleep and generate a tremendous amount of data without providing the tools people need to understand it," Cloud explained.
Your sleep might look different ― and that's okay.
The new metrics describe good-quality sleep, Sabra Abbott, a neurologist who specializes in circadian rhythm and sleep disorders at Northwestern Memorial Hospital, told HuffPost. But not everyone's sleep looks the same, she added.
"Just because you aren't able to perfectly meet these four guidelines, it doesn't necessarily mean that you have poor-quality sleep," Abbott said. The metrics "are useful as an initial target."
If your sleep does not meet these measures, that's reason to check what needs improvement ― like spending too much time awake in bed at night, which can make insomnia worse. (If you can't fall asleep within 20 minutes of waking up in the middle of the night, you should actually get up and do something else to help you relax ― like listening to music or reading. Lying awake in bed can create an unhealthy link between your bed and not sleeping, according to the National Sleep Foundation.)
Not meeting the new metrics may also be a sign of an undiagnosed sleep disorder, like sleep apnea, sleep-wake phase disorder (where your body clock does not run on average time) or insomnia, which can all be treated, Abbott said.
Another important indicator of getting good sleep is how you feel when you wake up, and during the day. "Do you have any reason to think you could be getting better sleep, or you feel tired during the day?" Abbott asked.
Answering yes to either of those questions, or not meeting the new quality sleep metrics, are red flags, and you should discuss these issues with your physician, Abbott said. Talking about your sleep habits and patterns with your primary-care doctor is just as important as talking about diet and exercise, she said.
"The intent [of the new report] was not to diagnose the public with potential sleep disorders, but rather to provide information to empower people and help them gauge their sleep health," Cloud added.
Another finding from the report was the need for more research to better understand the parameters of good-quality sleep ― especially which measures correspond to good long-term outcomes for other health measures, Cloud added.
"Ultimately, a better understanding of sleep quality is key to unlocking sleep health overall," Cloud said.
Sarah DiGiulio is The Huffington Post's sleep reporter. You can contact her at sarah.digiulio@.