Can Sleep Kill You?




It is a medical fact that too much sleep or too little sleep can kill you.



Sleep is a good thing, unless you have too much or too little. Where have we heard that before - everything in moderation. However you would think more sleep would be just fine because it feels so good, especially on a rainy day.



We've always been told that getting a good 8-10 hours sleep every night is required and it is a good thing. This may be a hold over in our memory as a child when our parents wanted us to go to bed at 8 pm to be rested for school the next day. In this case though, we are not talking about growing children, but healthy adults.



As we will find out below from various studies, getting eight hours of sleep each night might be bad for your health. According to data from the Cancer Prevention Study II, individuals who average seven hours of sleep each night have a lower mortality rate than do those who sleep eight hours or more. This information on sleep may help you find some fast answers to your problem.



"The lowest [mortality] group actually slept between six and one-half to seven and one-half hours," said Daniel F. Kripke, MD, a Professor of Psychiatry at the University of California, San Diego. "The major mortality risk associated with habitual sleep duration is among long sleepers, by which I mean those sleeping eight hours or more. Incidentally, calling them long sleepers is accurate, because from the new data we know that the average American on weekdays sleeps about six and one-half hours."



Now here is where it gets very interesting. Think about how much time, on average you actually sleep per night. Ignore the late night parties, the newborn feedings and waiting up 'till your teenage child comes in at 3am. Just come up with what you think is your average time for sleeping each day (don't count the cat naps - those have actually been found to be beneficial - but that's another story).



OK - have you got your number? The results are.....



Dr. Kripke says, from the study results, that individuals who slept eight hours per night were 12% more likely to die within six years than were those who slept seven hours. The highest mortality rates occurred among men and women who slept more than eight and one-half hours. This group had at least a 15% increased risk of death.



Sleeping too much can really put you at greater risk for dieing. How about for too little sleep? Dr. Kripke says, as for short sleep, men who slept less than four and one-half hours and women who slept less than three and one-half hours also had at least a 15% increased risk of death. He presented these findings at the 16th Annual Meeting of the Associated Professional Sleep Societies.



Sleep Study History - Why so long in being reported?



The data was collected in 1959 for the first study by the American Cancer Society. Preliminary results from that study, called Cancer Prevention Study I, were published in 1964. The study at that time concluded that the best survival rates were experienced by men and women who slept seven hours a night. "It was a very highly consistent and significant result," said Dr. Kripke. However, he noted, "this study did not receive much attention from the sleep community at the time, because it was published in the cancer literature."



The original data was reanalyzed in 1979, and corrected by removing other contributing factors as would be found in any study of the general public. Dr. Kripke and colleagues found that the lowest mortality was again at seven hours, with some increase in mortality associated with short sleep and an even steeper increase with long sleep. Still, he said, many questions remained regarding other risk factors that were not taken into account.



In order to answer some of the outstanding questions and concerns about the data and it's results, in 1982 Dr. Kripke embarked on a new study. This was to be called Cancer Prevention Study II. This study questioned over 1 million participants between ages 30 and 102 about their sleep duration and frequency of insomnia. The participants were tracked and a follow-up was conducted after a six year waiting period. The data, again as in the original study, was filtered to eliminate as many other contributing factors as possible. This has taken a substantial effort as explained below.



32 Risk Factors filtered out



"In the new study, we were able to control simultaneously for 32 risk factors," he said. "It was a very big job to do Cox proportional hazard models in a million people with 32 covariates." These factors included age, race, education, marital status, and various habits, as well as sleep duration, insomnia, and sleeping pill use. The investigators also examined health predictors such as diabetes and hypertension, along with medication use. "These were chosen partly because of univariate analyses," said Dr. Kripke. "Of course, the studies were mainly designed to look at cancer predictors, so they didn't have every variable that we might wish," he added.



After studying all the factors, Dr. Kripke said that the mortality rates went down. "Control for other risk factors reduced the risk associated with short sleep more than with long sleep," he said. "The mortality rises more steeply on the long side than on the short side." Dr. Kripke said a slightly lower mortality rate was found among women sleeping four hours per night than among those sleeping eight hours, though "probably not significantly so".



So you can't sleep - maybe a good thing?



"Oddly enough, we found mortality ratios of less than 1.0 with increasing reported insomnia per month," Dr. Kripke reported. "That is, those who reported insomnia, when we controlled for other covariates, lived longer. I don't know if I believe that this is a reliable protective effect of insomnia, but that is what the data suggest." Also noteworthy, he observed, is that "when we controlled for sleep duration and insomnia, those who said they took sleeping pills had a significantly higher mortality."



The Long Sleep - maybe not so good?



A number of other studies have shown similar results regarding a higher mortality among long sleepers. According to Dr. Kripke, the studies "used a variety of techniques to measure comorbidity". "I can assure you that the increased mortality associated with long sleep epidemiologically is a very, very reliable finding. It's been available in the literature since 1964, and since then nobody has been able to do a study that could explain this association by comorbidities."



Summary - sleeping more than 8 hours a day or less than 4 hours a day, with no medically contributing factors, can put you in your grave a lot sooner than you would like.



There are proven ways to help combat this problem. Several simple suggestions are listed below:



1. Cut caffeine. Simply put, caffeine can keep you awake. It can stay in your body longer than you might think the effects of caffeine can take as long as eight hours to wear off. So if you drink a cup of coffee in the afternoon and are still tossing at night, caffeine might be the reason. Cutting out caffeine at least four to six hours before bedtime can help you fall asleep easier.



2. Avoid alcohol as a sleep aid. Alcohol may initially help you fall asleep, but it also causes disturbances in sleep resulting in less restful sleep. An alcohol drink before bedtime may make it more likely that you will wake up during the night.



3. Relax before bedtime. Stress not only makes you miserable, it wreaks havoc on your sleep. Develop some kind of pre-sleep ritual to break the connection between all the day's stress and bedtime. These rituals can be as short as 10 minutes or as long as an hour.