Return to Transcripts main page
CNN Live Sunday
Interview With Sleep Disorder Specialists Daniel Kripke, Phyllis Zee
Aired February 17, 2002 - 17:44 ET
THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.
THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.
FREDRICKA WHITFIELD, CNN ANCHOR: Well, it seems to go against conventional wisdom, not to mention what our mothers have always told us. You got to get your eight hours sleep.
But a new study finds people who get only six to seven hours of sleep a night have a lower death rate than those who sleep eight hours or more. Joining us now to talk about these findings, just published in the Journal of American Medical Association are Dr. Daniel Kripke, lead author of the study, and Dr. Phyllis Zee, a sleep disorder specialist at Northwestern Memorial Hospital.
Well Dr. Kripke, let's begin with you. You got some explaining to do here. Most of us thought it was a complete antithesis of what your study is saying. We all have been conditioned to believe that its eight hours of sleep that you need in order to live a long, strong, health life.
DR. DANIEL KRIPKE, PSYCHIATRY PROFESSOR, UCSD: That's what people have been saying. But in fact there have studies for 35 years, showing that people who sleep especially more than seven or eight hours, do have a higher mortality. So it does appear quite safe to be a five, six, or seven-hour sleeper, as long as you're not sleeping in the day.
WHITFIELD: And so, in your study, you studied women who were the average age of 58, men the average age of 57, is that right?
KRIPKE: That's right.
WHITFIELD: OK, and of that study, you discerned that people between the ages of 30 and 102, getting between six to seven hours a night will live longer than those who get eight hours sleep, and what were their medical conditions? Does that have anything to do with the conclusion of your study?
KRIPKE: Well, we did our best to control for other medical conditions. In fact, we controlled for 32 health risk factors, things like obesity, cigarette smoking, heart disease, and so forth. As far as we could, we controlled for other health factors, but it is possible there are some explanations that we didn't control for.
WHITFIELD: And, how about things such as lifestyle? Oftentimes, people have very stressful lifestyles, jobs, et cetera. They think it's natural to need and want more sleep and perhaps get it if they can. But your study is almost indicating that they shouldn't do that?
KRIPKE: Well we showed, we did control for occupation and being upset, for exercise, for churchgoing, but we don't find that people who work sleep a much different amount from people who don't work, and we are not able to explain why this is. We don't know the cause. What we can advise people today is, if you feel rested during the day but sleep on five, six or seven hours, you shouldn't worry.
WHITFIELD: So Dr. Zee, let's bring you in. I imagine the makers of sleep disorder products and those who are prescribing them are not liking what they're hearing here at all. What's your beef with this study?
DR. PHYLLIS ZEE, SLEEP DISORDER SPECIALIST: Well my beef is that, as Dr. Kripke said, we don't know what the cause of this association is and because we don't know what the cause of the association is, we can not conclude that there is a true relationship between the number of hours, or the duration of sleep, with longevity, or with decreased longevity.
For example in the study, that of Dr. Kripke, they ask how many hours on the average do you sleep? That really included only nighttime sleep. The older population, you would expect in older people maybe either sleep less and take naps, for example, and the napping it could be half, an hour, two hours. That was not considered in the total amount of sleep, and that could have swayed the numbers, the number of hours of sleep, the mean number, a little bit higher.
WHITFIELD: And so Dr. Zee, should all of us be walking away from this study now, thinking we thought it was stress that shortened our lives. Now we're finding out that sleep might be shortening our lives?
ZEE: Absolutely not. I think it's very important for the public to recognize that getting enough sleep is good for you, and in fact, even mild amounts of sleep deprivation has been associated with poor daytime functioning.
And more recently, there's a large amount of evidence showing that sleep loss, sleep deprivation is associated with increased risk for possibly heart disease, and really helps risk metabolic diseases like diabetes. So there's really no evidence that getting enough sleep or shortening the amount of sleep that you need is good for you. In fact, it's bad for you.
WHITFIELD: And Dr. Kripke, adding on to Dr. Zee's list, I've also seen that not having enough sleep also certainly offers a decrease in your cognitive and physical performance. So what should we take away from your study that all of us would be able to use that might be helpful to our well-being?
KRIPKE: Actually, there's no evidence that eight-hour sleepers are healthier or happier or earn more money. I'm not at all sure that that's true. People should get as much sleep as they need to feel alert, but if they don't feel they need eight hours, as most Americans don't, then they shouldn't worry about it. That's the point of the study.
WHITFIELD: I know you've gotten a lot of flack for this, haven't you, since you had this study published?
KRIPKE: Well the study shows that people who took sleeping pills have higher mortality. I don't think the sleeping pill companies like that. But that is what the study showed.
WHITFIELD: All right. Thanks very much Dr. Phyllis Zee and Dr. Daniel Kripke for joining us and now giving us yet one more thing to ponder about as we hit our pillows this evening, trying to figure out, should it be six, should it be seven, should it be eight hours tonight? All right, thanks a lot, both of you for joining us.
TO ORDER A VIDEO OF THIS TRANSCRIPT, PLEASE CALL 800-CNN-NEWS OR USE OUR SECURE ONLINE ORDER FORM LOCATED AT www.fdch.com
