How Bright Light Therapy Helps with Low Mood, Sleep Problems and Jet Lag
By Daniel F. Kripke, M.D.
Last Revised April 2013
Good Sleep Habits
Since much of this book has been about using bright light to sleep better, it may surprise you that I think many people try to sleep too much. We are all familiar with the unpleasant feeling of having slept too little, but many of us have not thought about the possible harm of trying to sleep too much.
You may have heard somewhere that 8 hours of sleep per night is necessary to be healthful. This just is not so. In our studies in San Diego, the average adult is actually asleep only between 6 and 6.5 hours a night. Moreover, The Cancer Prevention Study II showed that people who report sleep of 6.5 to 7.5 hours live a bit longer than people who sleep 8 hours or more. The shorter sleepers lived longer! Even people who slept as little as 3.5 hours lived longer than those who slept 8 hours or more. Certainly, if you get only 6.5 or 7 hours of sleep a night, you are probably sleeping enough. Incidentally, when we record sleep in people above age 60, the amount of brain wave sleep is often about an hour less than the person reports on a questionnaire. In a study of elderly volunteers for the women’s health initiative, we found that women whose recorded sleep was 5.0 to 6.5 hours lived the longest.
Studies show that in the range that most Americans sleep (which is 6, 7, or 8 hours or so), there are few discernable differences between people. This may surprise you, but people who sleep 6 hours seem to be at least as happy as people who sleep 8 hours. Moreover, people who sleep 8 hours get just as much work done and are just as rich as people who sleep 6 hours. There may be some tendency for people with the shortest sleep times (5 or 6 hours) to be outgoing and energetic, whereas people with the longest sleep times (9 or 10 hours) seem to be more introverted, imaginative, or perhaps a bit depressed. Notice the surprise! People who sleep a bit less than average may be less depressed!
Indeed, hospital studies of depressed patients show something very surprising. When depressed patients are kept awake all night (or at least for the second half of the night, e.g., after 2 AM), they actually feel less depressed the following day. The sleep loss actually helps depressed mood. This was part of the wake treatment which Dr. Neumeister and Dr. Kasper used, and which is now a part of chronotherapeutics. Moreover, after the wake therapy, taking a nap makes depressive symptoms recur. Wake therapy would be a very popular treatment for depression except for one problem: people with depression who stay up during the night do get sleepy, and after they sleep soundly the next night, the low mood usually relapses (unless bright light is used). Evidently, although it is true that people who are getting depressed have poor sleep, it is not true that getting more sleep helps depression. Often it is quite the opposite.
For these reasons, depressed people should not struggle to get more sleep. People may actually improve their moods by getting up a bit earlier.
There is another factor. Spending too long in bed – as you might expect – causes people trouble with falling asleep and makes them more likely to awaken while in bed. Sometimes, the frustration of lying in bed awake adds to the problem, and it builds on itself, getting worse and worse. The more time the person spends in bed trying to get more sleep, the more trouble develops in falling asleep and the more the person awakens in the night. Surprisingly, it seems that spending too long in bed might be a major cause of sleep trouble among both elderly and depressed people. Fortunately, there is an easy solution.
People who are spending a lot of time in bed lying awake should spend less time in bed. This means either going to bed later or getting up earlier. Getting up by a regular time seems to be important, so trouble falling asleep should not persuade you to sleep late. The less time you spend in bed, the more sleepy you will be the next evening. Think about it. If you spend less time in bed, you will surely tend to fall asleep more easily and sleep more soundly in the future. Moreover, the less time you spend in bed, the more you will restore the habit of falling asleep quickly after going to bed, and the more you improve the habit of sleeping soundly. Some doctors would recommend that you should not spend more time in bed than you actually sleep. If you think you only sleep 5 hours a night, spend only 5 hours in bed until you are sleeping all 5 hours. Then you can try increasing time-in-bed about 15 min., e.g., to 5 hours and 15 minutes. You can gradually increase your time in bed on a weekly basis until you are no longer sleepy enough to sleep at least 85% of your time in bed. Once you are sleeping only 85%, that is the longest bed time which you should allow yourself.
Most sleep experts also recommend that whatever bedtime you allow yourself, you should not go to bed if you do not feel sleepy. Moreover, if you awaken at night and no longer feel sleepy, get out of bed, and do not go back until you are sleepy again and expect to fall asleep. Even after being up during the night, you should get out of bed by your regular awakening time, because sleeping late tends to make the problem worse. Getting out of bed when you are not sleepy makes you sleepier the next night and helps maintain good sleep habits.
Almost all of us have stayed up entirely for a night or two, so we know that nothing terrible happens to us. Many of the patients I talk to say that they have slept only a few hours a night for years, and yet they are somehow afraid that losing sleep will hurt them. Probably not. Remember that if anything, the short sleepers tend to live longer and be less depressed. If you are willing to stay out of bed and amuse yourself somewhere else when you are not sleepy, soon you will stop worrying about sleep. If you lose a whole night’s sleep or part of a night, so what? It will not be so bad, as long as you do not worry about it. When you do go to bed (because you are finally sleepy), you will have restored your confidence that you are likely to fall asleep, so the long-term problem resolves.
It is extremely common that depression, advanced sleep phase, or delayed sleep phase lead to poor sleep habits, and then the poor sleep habits become part of the problem. For this reason, it is important to observe good sleep habits when you are using bright light, in order to restore your sleep confidence. It has been shown specifically that sleep restriction can reduce depression.
If bad sleep habits are part of your problem, the website CBTforInsomnia.com can give you more detailed pointers about how to correct sleep habits. This is a commercial web site in which I have no financial interest. DO NOT USE THE POPULAR SLEEPING PILLS: they are too dangerous. For more information about the risks of sleeping pills, see my eBook, The Dark Side of Sleeping Pills. or visit the website.
Table of Contents
Brighten Your Life, in all its formats, including this eBook, copyright ©1997-2013 by Daniel F. Kripke, M.D. All rights reserved.