We’ve all been there—lying in bed, waiting for sleep to come. After tossing and turning for what seems like an eternity, you ask yourself: should I give up and get out of bed? Or am I overreacting? How long am I supposed to be lying here? Good question.
How long it takes to fall asleep is a slippery concept, and one that unhappy insomniacs grasp at as they lie awake from one minute to the next. Given the hazy state of mind that sets in when we lie sleepily in bed, it can become difficult to remember clearly just how long it usually takes for sleep to arrive, adding more uncertainty and stress when it seems to be taking too long. Fortunately, there has been research into this issue.
The study of sleep latency
The amount of time it takes you to fully transition from wakefulness to sleep is known as sleep latency, and the pioneer of research into the subject is a researcher at Stanford named William C. Dement. He was the first to develop a test that measures how long it takes to fall asleep: the Multiple Sleep Latency Test (MSLT). In the test, he had subjects rate how tired they felt on a sleepiness scale before lying down in a quiet, dark room. He then measured how long it took them to fall asleep, from 0 to 20 minutes, with subjects’ sleep latency score increasing the longer it took them to fall asleep. If a subject was still awake after 20 minutes, the experiment ended.
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The study found that subjects’ sleep latency was closely correlated with their own self-evaluated level of sleepiness. Now this might not seem like a mind-blowing revelation, but it was the first ever conclusive evidence that the mind and body know how tired they are, and that this knowledge directly impacts sleep behavior. This study also gave rise to the notion of “sleep debt”, showing that the brain keeps track of how much sleep it is owed—and the greater the debt, the lower the sleep latency score. In severely sleep-deprived subjects, sleep latency scores could fall below one, meaning subject fell asleep in under one minute.
Dement’s study and future research into sleep latency found that, on average, it takes between 10 and 20 minutes to fall asleep. A commonly-cited factoid states that it takes seven minutes for the average person to fall asleep, which can fit with this research depending on what you classify as “sleep"; it takes about seven minutes to reach a state where alpha brain waves dominate and we achieve a state between sleeping and waking—we might describe it as dreamlike, hazy, and peaceful, and it may even come with mild hallucinations.
We remain in this in-between state for five or so minutes, and then theta waves take over and we transition into the first stage of full, if light, sleep. This brings the total transition time from awake to asleep to somewhere around 15 minutes.
If you’re on either extreme of the sleep latency spectrum—taking less than five or more than 20 minutes to fall asleep—your body is trying to tell you something. Conventional wisdom goes that if it takes you less than five minutes to fall asleep, you’re extremely sleep-deprived; if you fall asleep within 5-10 minutes, you’re dealing with moderate sleep debt; between 10-20 puts you in the average, healthy zone; if it’s taking you longer than 20 minutes to fall asleep each night, you may be sleeping too much, or it could be a matter of poor sleep hygiene.
You didn’t think we’d get through this post without talking about sleep hygiene, did you? Putting aside a handful of other factors (like medical or psychological issues or a bed that doesn’t provide proper comfort and support), sleep hygiene is the number one place to look if it takes you a very long time to fall asleep. Before you start looking for some big underlying issue, ask yourself the following questions:
- Is your bedroom sufficiently dark?
- Is your bedroom sufficiently quiet?
- Is your bedroom sufficiently cool?
- Has it been at least 3 hours since you drank alcohol or ate a large meal?
- Has it been at least 10 hours since you had caffeine?
- Has it been at least 1 hour since you spent time looking at a screen (phone, TV, computer, tablet)?
If you answered no to any of these questions, try to tweak your habits to create an environment more conducive to sleep. If you answered yes to all of them and are still having trouble falling asleep, your body is likely trying to tell you something. We strongly recommend that you talk with your doctor if this is the case for you.
 Dement, William C.; Christopher Vaughan (1999). The Promise of Sleep: A Pioneer in Sleep Medicine Explores the Vital Connection Between Health, Happiness, and a Good Night’s Sleep. Dell Trade Paperbacks. ISBN 0-440-50901-7. pp. 58–59.