Return to Transcripts main page

American Morning

Interview of Daniel Kripke, Sleep Researcher

Aired February 15, 2002 - 09:22   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.
ANDERSON COOPER, CNN ANCHOR: The big question this morning, will less sleep help you live longer? Researchers at the University of California in San Diego say, yes. Their new study found that people who sleep more than eight hours a night or less than four have higher death rates. Dr. Daniel Kripke is the author of the sleep study, and he joins us now from San Diego. Thanks very much for being with us. There is a lot of detail in your report that we really can't get into, but bottom line, what is the optimum amount of sleep a person should get?

DANIEL KRIPKE, SLEEP STUDY AUTHOR: The study showed that people who sleep about seven hours live the longest, but people who sleep either less than seven hours or, perhaps, eight hours, don't have substantially increased risks.

COOPER: I know the common belief, you know, for years, I was always told as a child, is that you need at least eight hours' sleep. Are you saying that is now incorrect?

KRIPKE: I think it's incorrect in terms of mortality. It's clear that people who sleep eight hours or more do not live longer.

COOPER: All right. The National Sleep Foundation has written a response to your article, saying that, in effect, the study doesn't allow conclusions to be drawn about the amount of sleep needed for optimum health. How do you respond?

KRIPKE: Well, ours was a study of mortality, what sleep duration is associated with the longest life. And it's true that we didn't, in this study, measure health, measure function. But, in other studies in San Diego, we have measured function, and we found that six hour sleepers and eight hour sleepers had just about the same health.

COOPER: Can your study explain why someone who sleeps longer has a higher mortality rate?

KRIPKE: No, we really can't. We don't know the causes, and specifically, we don't know if long sleep is the cause, so we don't know if setting the alarm clock earlier would be of any benefit.

COOPER: So, that's an important point to make, and it is also it is one the National Sleep Foundation writes in a parallel article to the article that is coming out in "Nature." They are basically saying that if someone is sleeping now eight and a half, nine hours, and feels energetic, feels alert, feels good, they shouldn't necessarily cut back on their sleep based on your research. Do you agree with that?

KRIPKE: Oh yes, I agree. We're not recommending that people cut back on their sleep. Whether that would work is something for which we need future research. At the current time, we don't have any evidence that people should cut back on their sleep.

COOPER: We're seeing video of people yawning. I got to tell you, I'm starting to yawn. Do -- how big a study was this? I mean, this seems the most detailed study that has come out in quite a while.

KRIPKE: It is. American Cancer Society volunteers gave health questionnaires to 1.1 million people and followed them, prospectively, for six years. So, it might be the biggest sleep study ever done.

COOPER: All right, Dr. Daniel Kripke, thank you very much for joining us this morning. It's a very interesting study, I enjoyed reading it. Thanks very much for being us, Dr. Kripke.

TO ORDER A VIDEO OF THIS TRANSCRIPT, PLEASE CALL 800-CNN-NEWS OR USE OUR SECURE ONLINE ORDER FORM LOCATED AT www.fdch.com