How much sleep do we need?

Although everyone differs in the amount of sleep they need, here are some general guidelines:

infancy/toddler : 16-20 hours
4 year old: 12-14 hours
10 year old: 10-12 hours
18 year old: 9-11 hours
30 year old: 8-9.5 hours
60 year old: less than 7-9 hours

If you think there aren't enough hours in a day for you to get enough sleep in your busy schedule, don't despair. There are various ways you can manage your sleep debt during the week and catch up on the weekends. You may also be a person who doesn't need as much sleep as others. The key is to find out how much sleep you need and this lesson will give suggestions for finding out.

Our grandparents and great grandparents who lived before electricity was installed in homes slept 9-10 hours a night. They went to bed soon after the sun went down and got up with the sun in the morning. There was a natural change in sleep lengths that followed the seasons - more sleep in winter, less in summer. Nowadays, most of us are getting 7 or 8 hours of sleep per night. We are a culture of sleep deprived individuals.

We are living longer than our grandparents in spite of getting less sleep. Our grandparents died of diseases that we hardly think of now - diphtheria, flu, pneumonia. They did not have antibiotics to fight these diseases the way we have today. So think about how much longer we could live if we kept ourselves healthy by sleeping more.

To Do:

How can we know our own individual sleep needs? Here are some methods to calculate your need.

1. Most people have a general idea of how much sleep they need. So let's say you think you need 8 hours of sleep per night. Decide when you have to get to bed to get this 8 hours. Then go to bed at this time, and set your alarm for 8 hours and 15 minutes later. (The fifteen minutes is the time it should take you to fall asleep.) Keep track of how you feel during the day (see charts from lesson 1) and if you're getting too sleepy, add half an hour to your night's sleep by either going to bed earlier or getting up later. Keep doing this until you find that you're functioning at an optimal level throughout the day. When you've reached this point, you'll know how much sleep you need. You may be pleasantly surprised to find you only need another half hour per day or you may find that you're seriously short-changing yourself.

2. Another calculation method is to take a vacation at least 2 weeks long, sleep late until you've caught up on all your sleep debt and then allow yourself to sleep as long as your body wants. Note the approximate time you go to sleep and the time you wake and want to get up. When you sleep like this, without stress, you'll get a good idea of how much sleep you really need. It might surprise you to find how many hours your body is actually asking for. This method is great if you're already scheduled for a holiday but is not practical otherwise.

Are you sleep-deprived?

Although they don't tell you how much sleep you need, the following tests can indicate whether you're sleep deprived.

1. Try a sleep latency test. In a sleep lab, you would be hooked up to an EEG machine which would accurately measure how long it takes you to fall asleep. Although it's not quite as accurate, you can still get a pretty good idea at home. Notice the time when you lie down to sleep. Lie down with a spoon held in your hand; drape your hand over the edge of the bed and over a plate that you've placed on the floor. Your hand will relax and release the spoon when you fall asleep, the spoon will clatter onto the plate and wake you. Then you look at the clock to see how long it took you to fall asleep. If you fall asleep very quickly, you're sleep deprived. (See chart below.)

Minutes to fall asleep	Amount of Sleep Debt
1-5	Severely sleep deprived - check with a sleep clinic to see if you have a sleep disorder
5-10	Troublesome amount of sleep debt (likely to fall asleep while driving)
10-15	Manageable amount of sleep debt
15-20	Little or no sleep debt

2. You can also take a subjective measurement by rating yourself with the test in the following charts. Rate your tendency to fall asleep in various situations as described, using the Epworth Sleepiness Scale¹.

Epworth Sleepiness Scale:

0 = no chance of dozing

1 = slight chance of dozing

2 = moderate chance of dozing

3 = high chance of dozing

Situation	Your Chance of Dozing
Sitting and reading	___
Watching TV	___
Sitting inactive in a public place (e.g. a theater or a meeting)	___
As a passenger in a car for an hour without a break	___
Lying down to rest in the afternoon when circumstances permit	___
Sitting and talking to someone	___
Sitting quietly after a lunch without alcohol	___
In a car, while stopped for a few minutes in traffic	___

Evaluate your total score:
0-5	Slight or no sleep debt
6-10	Moderate sleep debt
11-20	Heavy sleep debt
21-25	Extreme sleep debt - get help!

Besides knowing whether you're sleep deprived or not, take note of your feelings. Does 10 hours of sleep debt impair you only a little or do you feel awful and unable or unmotivated to do anything? It's important to have this self knowledge. But be honest - our culture glories in hard work over long hours and admitting you need more sleep goes against this culture.

Footnotes:

1.The charts in this lesson come from Dement, William C. and Christopher Vaughan, The Promise of Sleep, Dell Publishing, New York, 2000. chapter 15, p 339-342

Contents

How much sleep do we need?

To Do:

Are you sleep-deprived?

Footnotes: