2

votes

5 to 6.5 Hours of Sleep Ideal for Longevity?

Answered on August 19, 2014
Created October 01, 2010 at 2:11 PM

News about a new sleep study here: http://ucsdnews.ucsd.edu/newsrel/health/09-30sleep.asp

???The surprise was that when sleep was measured objectively, the best survival was observed among women who slept 5 to 6.5 hours,??? Kripke said. ???Women who slept less than five hours a night or more than 6.5 hours were less likely to be alive at the 14-year follow-up.???

We'll have to see the full study to understand what they mean by "measured objectively" ... I get about 6 hours per night and feel very energetic throughout the day and actually find these results to be encouraging, although it is specific to women at this point.

Any initial reactions?

26b7615ef542394102785a67a2786867

(7967)

on March 21, 2011
at 02:41 AM

Right there with you. I *can* sleep for 9 or 10 hours easy - doesn't mean I should! I never felt more rested when I slept a lot. Now I feel my best by far with 6 or 7, more makes me logey all day...

62ed65f3596aa2f62fa1d58a0c09f8c3

(20807)

on October 02, 2010
at 01:35 AM

LMAO! It was all older people. That explains a lot. And you are right, ridiculous irresponsible spin it ubiquitous in the media. There really should be some kinds of standard and rules about that kind of thing! I have heard many researchers complain about it themselves.

F5698e16f1793c0bb00daea6a2e222a4

(678)

on October 01, 2010
at 06:43 PM

agree! http://en.wikipedia.org/wiki/Siesta :)

89e238284ccb95b439edcff9e123671e

(10299)

on October 01, 2010
at 05:46 PM

I agree! And another thing that probably is difficult (should have access full paper to check study design and methods), is the reliability of the reported hours of sleep. Over 14 years!

89e238284ccb95b439edcff9e123671e

(10299)

on October 01, 2010
at 05:44 PM

Yep, that's what I meant with difficulties of interpretation of these studies

89e238284ccb95b439edcff9e123671e

(10299)

on October 01, 2010
at 05:43 PM

No, I haven't. TEDtalks should have references. She did write a book.

B294438548c32ed878905baf6cd1b332

on October 01, 2010
at 05:24 PM

Pretty cool. Watched it -- have you found more data on the 2-hour meditative state that she brought up near the end? I hadn't heard of that before.

B294438548c32ed878905baf6cd1b332

on October 01, 2010
at 05:17 PM

If I could totally have my way, I'd get about 5.5 - 6.5 at night and 45 minutes to an hour after lunch. I'd probably live to be as old as Yoda if I could actually do that.

Frontpage book

Get FREE instant access to our Paleo For Beginners Guide & 15 FREE Recipes!

7 Answers

best answer

2
62ed65f3596aa2f62fa1d58a0c09f8c3

(20807)

on October 01, 2010
at 05:41 PM

Exactly as David said. SOunds like this is an epidiemiological study which means it can't determine cause. Sick people sleep more. Depressed people sleep more. People with busy lifestyles sleep less. Older people sleep less. You would have to separate out all those causes and more before you could even start to guess at any other causal relationships. Plus there was a 14 year gap between the data taken and the followup. Many of those people's sleep habits could have changed drastically in that time frame.

I will still stay with my usual advice which is sleep as much as your body seems to want on any given day. That's the natural way and lack of sleep stresses the body. Sleep needs are highly individual and definitely not an area where you will want to try force yourself into some kind of preset mold just because of the outcome of one shoddily done study. If you ask me, it was irresponsible of those researchers to suggest a specific sleep time based only on that flimsy data.
-Eva

89e238284ccb95b439edcff9e123671e

(10299)

on October 01, 2010
at 05:46 PM

I agree! And another thing that probably is difficult (should have access full paper to check study design and methods), is the reliability of the reported hours of sleep. Over 14 years!

best answer

10
25ed4acfb632d928507f8673bcb0923a

(650)

on October 01, 2010
at 10:48 PM

http://www.ncbi.nlm.nih.gov/pubmed/20870457

The title of the original article is "Mortality related to actigraphic long and short sleep."

Here are a few points:

  1. The results are based on data collected from 1995-1999. "Actual sleep" was determined by an actigraph, sort of like a pedometer worn on the wrist.

  2. The results are based on estimated survival, not actual morality rates, because many women could not be contacted in the follow-up.

  3. From the article, "Subsample recruitment was deliberately structured to include as many older women as possible to increase the power of mortality analyses."

  4. The age range of the women in the study was 50-81. We know that older people sleep less than younger people.

  5. The authors do not make causal claims in the original article. It is typical for the popular media to spin it that way, though.

  6. Unfortunately the data are not fully consistent with their predicted u-shaped conclusion, because the average estimated survival rates for those women who slept less than 4 hours and also for those who slept more than 7.5 hours are nearly the same (86%) as those who slept 6-6.5h (90%). The lowest survival estimates were in the 4.5-5h (54%) and 7-7.5h (58%) sleep duration categories.

  7. There is huge variability in the risk ratio of the two "worst" sleep duration categories: in the 7-7.5 and 4.5-5 hour rages. In my opinion, this helps explain why the results from these categories are so different from all the other categories.

  8. Reported sleep is almost always longer than actual sleep, so the women who actually slept 6-6.5 hours probably reported about 7 hours of sleep.

62ed65f3596aa2f62fa1d58a0c09f8c3

(20807)

on October 02, 2010
at 01:35 AM

LMAO! It was all older people. That explains a lot. And you are right, ridiculous irresponsible spin it ubiquitous in the media. There really should be some kinds of standard and rules about that kind of thing! I have heard many researchers complain about it themselves.

4
E35e3d76547b18096a59c90029e7e107

(15613)

on October 01, 2010
at 05:10 PM

This is fairly straightforwardly confusing cause and effect. Other studies have found that people who sleep less are healthier, but this isn't telling us whether healthier people need to sleep less, or sleeping less makes people healthier. Only the former looks particularly plausible.

It's analogous to the confusion over cholesterol: people who haven't damaged their bodies and thus require higher levels of cholesterol for repair will have lower levels of cholesterol, but this by no means implies that lowering the level of the substance that repairs said damage- cholesterol- will make you healthier.

89e238284ccb95b439edcff9e123671e

(10299)

on October 01, 2010
at 05:44 PM

Yep, that's what I meant with difficulties of interpretation of these studies

2
77877f762c40637911396daa19b53094

(78467)

on March 21, 2011
at 12:06 AM

I am sleeping 6.5 hours per night max., working out 6-7 days per week(30-45 min. weights, supersetting sets, 30-40 min cardio twice per day, zero carbs, 3000 kcal.)---and I have never felt better! I used to sleep for up to 9 hours thinking it was healthy. Boy what a waste of time!

26b7615ef542394102785a67a2786867

(7967)

on March 21, 2011
at 02:41 AM

Right there with you. I *can* sleep for 9 or 10 hours easy - doesn't mean I should! I never felt more rested when I slept a lot. Now I feel my best by far with 6 or 7, more makes me logey all day...

2
89e238284ccb95b439edcff9e123671e

(10299)

on October 01, 2010
at 02:57 PM

I'd like to point to this short TED-talk about natural sleep.

Like you say, it would be interesting to see the whole study. A lot of difficulties with this kind of studies. No time to go into this for now.

89e238284ccb95b439edcff9e123671e

(10299)

on October 01, 2010
at 05:43 PM

No, I haven't. TEDtalks should have references. She did write a book.

B294438548c32ed878905baf6cd1b332

on October 01, 2010
at 05:24 PM

Pretty cool. Watched it -- have you found more data on the 2-hour meditative state that she brought up near the end? I hadn't heard of that before.

1
F5698e16f1793c0bb00daea6a2e222a4

(678)

on October 01, 2010
at 06:42 PM

imo people have different needs (sleep, nutrients, etc.) based on genetics and also how they live.

For instance my wife leads a hectic and stressful life (she likes it this way) and needs 8 hours at night. I don't live/work like that and do fine with 6.5.

1
A68f24168bc0de414a038037e287b581

on October 01, 2010
at 03:09 PM

I know without any research and just from observation, that if I sleep less than 6.5 hours I feel like a zombie, with flu-like symptoms. I can do one day with 7h if I sleep more the next day. Generally I try to aim for 7.5-8h to feel good. And I won't even mention that today I slept for 10h...(I have a day off!)

But we know very well that observation of one factor can lead to many mistaken conclusions. What if women who sleep 5-6.5h tend to also eat healthier?

B294438548c32ed878905baf6cd1b332

on October 01, 2010
at 05:17 PM

If I could totally have my way, I'd get about 5.5 - 6.5 at night and 45 minutes to an hour after lunch. I'd probably live to be as old as Yoda if I could actually do that.

F5698e16f1793c0bb00daea6a2e222a4

(678)

on October 01, 2010
at 06:43 PM

agree! http://en.wikipedia.org/wiki/Siesta :)

Answer Question


Get FREE instant access to our
Paleo For Beginners Guide & 15 FREE Recipes!