A good night's sleep is something that many have trouble experiencing, but there has also been a bit of confusion regarding what it is that defines a high quality slumber.
The National Sleep Foundation questioned a panel of experts and has come up with a list of factors that characterize good quality rest.
Among them are spending at least 85% of one's time in bed asleep and taking no more than 30 minutes to arrive at that state.
RELATED: Sleep tips
Other key indicators of satisfactory sleep involve prolonged rest, experiencing an interruption only once, and not exceeding 20 minutes of wakefulness after sleep sets in for the first time.
The National Sleep Foundation encourages the use of the many sleep-monitoring technologies available, as they can identify problems, which, it points out, would be "otherwise unknown."
It also notes in its Sleep Health Index that 27% of people do not fall asleep within the optimal 30-minute window.
Maurice Ohayon, director of the Stanford Sleep Epidemiology Research Center, commented, "In the past, we defined sleep by its negative outcomes including sleep dissatisfaction, which were useful for identifying underlying pathology. Clearly this is not the whole story. With this initiative, we are now on a better course towards defining sleep health."