You’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.