calculate your sleep need by keeping track of the hours you sleep on vacationYou’ve heard the advice to get 8 hours of sleep a night? Now they’re saying that 7 hours is the optimal amount of sleep–which may not be very cheering for most people with insomnia. Still our nights do not measure up.

As if that weren’t bad enough, the web is glutted with articles showing that short sleepers are vulnerable to a host of ailments: depression, heart disease, obesity, diabetes, dementia. Yikes! It’s a wonder any of us live past 65.

If you have persistent insomnia, and if you fall short of the recommended 7 or 8 hours, it’s natural to wonder if you’re getting enough sleep.

How Much Sleep Is Enough?

Sleep need—or sleep ability—varies a lot from one person to the next. Some people feel refreshed after 5 hours while others need 9. In normal sleepers, the duration of sleep is fairly consistent from one night to the next, so it’s easy to make inferences about sleep need. A person who under favorable conditions normally falls asleep at 11 and wakes up at 6 needs an average of 7 hours’ sleep a night.

But the sleep of people with insomnia is much more variable. Insomniacs are 60 percent more likely than good sleepers to sleep poorly on any given night. After a slew of bad nights, it feels heavenly to pop off a solid 8 hours. You wake up feeling rested and ready for the day—and this might lead you to infer that you need 8 hours a night to function at your peak.

But it’s a mistake to assume that the sleep you get on a night of recovery sleep is equivalent to the amount of sleep you need every night. It’s also wrong to assume that the 4 hours you more often get will suffice. The truth lies somewhere in between.

Track Your Sleep over Time

To find the amount of sleep you need for optimal functioning, keep track of the hours you sleep for a week or two and then take the average of that. This is probably closer to your daily sleep need.

But . . . this figure may be off the mark for people with persistent insomnia. Stress can interfere with sleep and make it hard to get an accurate read on sleep need. You may be slightly but chronically low in the tank.

A Better Way to Calculate Sleep Need

Eve Van Cauter, director of the Sleep, Metabolism and Health Center at the University of Chicago, suggested a better way to figure out sleep need or capacity in last week’s USA Today. Here it is:

Wait until you’re on vacation and free of the stressors connected to the daily grind. Once you’re away, go to bed at your usual time but do not set an alarm clock. The first few days you may sleep longer than normal to make up for the sleep debt you’ve accumulated at home.

Then, once your sleep stabilizes, start keeping track of how long you sleep. This, plus or minus 15 minutes, Van Cauter says, is as good a way as there is to get a handle on your daily sleep need.

Posted by Lois Maharg, The Savvy Insomniac

Lois Maharg has worked with language for many years. She taught ESL, coauthored two textbooks, and then became a reporter, writing about health, education, government, Latino affairs, and food. Her lifelong struggle with insomnia and interest in investigative reporting motivated her to write a book, The Savvy Insomniac: A Personal Journey through Science to Better Sleep. She now freelances as an editor and copy writer at On the Mark Editing.


  1. Finding the average over two weeks of a sleep pattern (or non-pattern!)sounds like a good idea. Even though I don’t have insomnia, I like reading your posts because sleep is an interesting subject. This morning, for instance, I woke up at 4:00 a.m. because last night I went to bed before 9:00. I’ve noticed that my fiction writing goes better when I have aimless daydreaming before I get up. I used to try hard to get back to sleep, but now I just drift and find it beneficial to writing. And get this: for several mornings now I have thrown back the covers at exactly 5:59 a.m., just one minute before the alarm goes off. Maybe we should just trust our deeper mind. Would this be true for insomniacs? Oh. One other thing, Lois: have you ever written about sex and sleep? Does it help? Now that I have a wonderful gentleman friend, I realize that it’s different sleeping alone and sleeping with someone else.



  2. P.S. That looks like Eric in the hammock!



  3. Hi Marlene,

    I don’t doubt that aimless daydreaming is good for your writing. My guess is you’re probably drifting in and out of REM sleep (a very light stage of sleep), most of which comes at the end of the night. That’s bound to benefit your mood & make you feel more alert when you do get up.

    If you’re waking up right before your alarm goes off, you’re probably getting the right amount of sleep. People with insomnia tend to be less regular, which is part of the problem for many of us.

    Sex and sleep? Now there’s a good topic for a blog. Look for it some time in the future!

    PS: Eric thanks you for the compliment.



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