How to tell if you've had a good night's sleep

After tossing and turning for what seems like hours, you come to terms with the fact that it'll be another sleepless night. But how can we tell if we've had a good night's sleep or not?

The Medical News Today editorial office is a melting pot of sleep issues. Whether caused by hormonal changes, anxiety, or young children who just won't sleep through the night, our sleep is a constant topic of conversation.

With 35 percent of adults sleeping for under 7 hours each night, according to the American Sleep Association, our team is a fairly representative sample of society.

Find out what sleep experts say the telltale signs of a good or bad night's sleep are, and why the data from sleep trackers doesn't necessarily reflect how we feel about our sleep quality.

Sleep quality

According to the National Sleep Foundation, over one third of people in the United States say that their sleep quality is "poor" or only "fair."

But what determines sleep quality? In a 2017 report published in the journal Sleep Health, the National Sleep Foundation assembled a team of sleep experts to define what indicates good-quality sleep. Here are some of the metrics that the panel agreed on.

Factors that contribute to good sleep quality in adults:

  • falling asleep in 30 minutes or under
  • waking up for under 5 minutes once per night
  • being asleep for 85 percent or more of the total time that you spend in bed
  • being awake in the night for under 20 minutes

Factors that contribute to bad sleep quality:

  • taking more than 1 hour to fall asleep
  • waking up on four or more occasions
  • sleeping for less than 74 percent of the time spent in bed
  • being awake for 41 minutes or more during the night

Interestingly, an editorial that accompanies the article highlights how difficult it is to measure sleep quality because it is a "subjective experience." The authors of the National Sleep Foundation report agree.

"Our findings highlight the multidimensional nature and complexity of sleep quality."

So, how do these metrics stack up against our personal perception of sleep quality?

What sleep trackers say vs. how you feel

A study published this week in the journal Behavioral Sleep Medicine followed 50 participants for 2 weeks.

Sleep quality as perceived by each individual was recorded in daily sleep diaries and compared with measurements taken by a wrist-worn sleep tracker, or actigraph.

The study found that two factors made the biggest contribution to the participants' perceived sleep quality: the number of times a person woke during the night, and how much time they had spent asleep during the previous night.

Interestingly, the authors point out that "the relationship between the actigraphy-based sleep characteristics and the perceived sleep quality was only modest."

So, your sleep tracker might show you that it measured a good night's sleep, but you could still wake up feeling groggy.

Whether we can use the tracker's data to convince ourselves that our sleep was better than we thought is a question that our team would like to see answered in the future.

For now, however, our perception of sleep quality will remain uniquely personal. But it might be worth bearing in mind how quickly we fell asleep, how often we woke during the night, and how long we lay awake, as well as how well we slept the previous night, before we cast our verdict about last night's sleep quality.