Followup on the Science of Sleep


It’s been a while since I wrote, and some of that is that I’ve been trying to get to bed earlier, and get a more consistent 8 hours of sleep. Since I last wrote, I saw an interesting factoid from an interview with Daniel Kripke, who is the co-director of the Scripps Clinic Sleep Center in La Jolla, California. In this interview, he talked about research he did on more than 1 million Americans that correlated sleep and mortality. There were some surprising findings, which have been corroborated by similar studies in other countries.

The results showed that those who slept between 6.5 and 7.5 hours a night lived the longest. And that those who slept more than 8 hours a night or less than 6.5 hours a night don’t live as long. This is interesting in that most previous writing I have seen suggests that sleeping more is good for you, but these data don’t support that.

Another good point he made was that when people try to get too much sleep, because they think the normal amount is 8 or 9 hours, they may unintentionally develop insomnia. Staying in bed longer than you can sleep will result in wakefulness, and anxiety about not being able to sleep. So for those of you who only can sleep 6.5 or 7 hours, just get up, it won’t hurt your health. In fact, restricting the time in bed is a more effective treatment for insomnia than sleeping pills, according to Kripke.

What we don’t know is which direction the causality runs in this association. Does the amount of sleep you get create your health status, or is it a reflection of underlying health? Do sicker people sleep too little or too much? Or does sleeping too little or too much make you sicker? No one knows for now, so I wouldn’t necessarily rush to change your sleep habits based on this study. But if you are sleeping in the 6.5 to 7.5 hour range, you can relax and not worry about it (especially late at night!)

Now I’ve got to stay up a little longer, so I don’t get too much sleep tonight…

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