How much sleep do you need?

You've probably heard it before: 8 hours for sleeping, 8 hours for working, and 8 hours for leisure (although that's not entirely true, because calling your commute time "leisure" is a stretch!).

But where does the idea that we need 8 hours of sleep come from? Why do we believe that at least eight hours of sleep per night is so important and that sleeping less can have harmful effects?

The myth of 8 hours of sleep

When people are asked how much they sleep, the answer usually falls in the 7 to 9 hour range, which is why the 8-hour convention became an approximate average of what most people believe they sleep.

However, preliminary results from one of the world's largest sleep studies¹, involving more than 10,000 people from different parts of the globe, showed that people sleep approximately 6.3 hours per night.

This belief may also be fueled by advertising. Spreading the negative consequences of not getting enough sleep is convenient for those who have an answer to this mythical medical problem - take a pill, and if that doesn't work, take two!

What isn't widely publicized are the effects of chronic use of the most popular sleep medications, linked to elevated mortality rates, increased drowsiness-induced accidents, dementia risk, among others.

But what do public health agencies and medical research say?

General recommendations

Studies that predict sleep needs in people generally consider the average population, not individual needs².

On average, people who sleep between 7 and 8 hours tend to perform better in terms of cognitive functions and memory¹. Even so, a study³ from the University of California that evaluated mortality rates in a population over 4 years reached the following conclusion:

People who sleep five or six hours can rest easy (they are outside the high mortality risk zone).

To understand how individual sleep needs can vary, the National Sleep Foundation⁴ recognizes that between 6 and 10 hours of sleep may be appropriate for people aged 26-64.

source: National Sleep Foundation

According to the American Academy of Sleep Medicine (AASM)⁵, the difference in sleep needs among individuals is influenced by genetic, behavioral, medical, and environmental factors. However, there is no clear understanding of how much sleep a person who has had insomnia needs per night.

So how much sleep do you need?

Different people need different amounts of sleep

What studies and recommendations tell us is that if, for example, you regularly sleep 8 hours per night but are still dozing off during the day, you're not getting enough sleep. On the other hand, if you only sleep 6 hours but never feel tired or lethargic during the day, you're obviously getting enough sleep. Different bodies require different sleep patterns.

Certain scientific experiments have concluded that we never sleep 8 consecutive hours, because we usually wake up in the middle of the night and fall back asleep. Therefore, don't worry too much about sleeping an exact amount every night. Quality is more important than quantity, which is why it's more beneficial to have shorter, better sleep than longer, poor-quality sleep (we've already seen this when we discussed the effect of alcohol in the blood). That's why the best way to recognize if you're not getting enough sleep is to look for the following signs.

Signs that you're not getting enough sleep

• You wake up during the night due to stress or a bad dream.
• You frequently sleep outside your normal sleep schedule and suffer from significant sleep inertia when you wake up.
• You are moody and easily irritable
• You're gaining weight even though you're eating properly and exercising.
• You have daytime sleepiness

Note that none of these determine how many hours you should sleep.

Conclusion: there is no "magic number"

What it all comes down to is that there is no 'magic number'² for the amount of hours you need to sleep.

To roughly calculate how many hours of rest your body needs, observe how it responded to the weeks of sleep restriction therapy and how it affected you the following day. Pay close attention to your mood and energy levels the next day.

I'm not suggesting that your sleep time doesn't matter. But if you're like most people with insomnia, that number is probably less important than you think.

If you're fortunate enough to increase your average nightly sleep time with the program, that's wonderful. But be careful about what target you focus on. Thinking too much about hours slept can make you more anxious.

Additionally, there are good reasons to believe that people who complete the CBT-I program will continue to slowly increase their average nightly sleep. But this happens long after they start feeling better.

What is your ideal amount of sleep? Share your thoughts on how many hours of sleep you get in the comments.