CR Sleep Survey Results!

[Dean Pomerleau]

Here are the results from the recent CR and Sleep Survey, as a follow-up to the General CR Survey conducted a couple weeks ago, whose results are available here.

 

This time where were 20 respondents, with 70% men and 30% women.

 

The age distribution was skewed much younger than the first survey. Here is the data (click to enlarge):

 

 

 

There was also a greater proportion of people with higher BMIs this time:

 

 

and with fewer years of CR under their belt, although we had a good contingent of veterans as well:

 

 

Overall, CRers reported sleeping about 6.8 hours per night on average. Here is the distribution:

 

 

Overall, CRers reported sleeping about 0.8 hours less per night on average since starting CR. Here is the distribution:

 

 

CRers reported that by far the most common sleep problem was "early waking". Here is the distribution of sleep difficulties:

 

 

Here are some interesting interactions between CR practices and sleep characteristics that showed up in the data. As usual, the numbers are small and so these should be taken as trends and with a grain of salt:

• While the number of reported nightly hours of sleep did not differ based on duration of CR, CR veterans (> 10 years) reported a greater reduction in sleep time than people who've been practicing less than 10 years (-0.91 vs. -0.21 hours, respectively).
• People who waited 2-4 hours between their last meal/snack and their bedtime reported less of a decrease in their time spent sleeping than either people who waited less than 2 hours, or greater than 4 hours before going to bed (-0.25 vs. -0.9 hours, respectively). So if you want to lose less sleep as a result of CR, it appears best to wait a moderate time between eating and going to sleep.
• The biggest impact on sleep seemed to be the result of BMI. People with a BMI less than 20 reported sleeping 40min less than those with a BMI > 20 (6.47 vs. 7.14 hours respectively). The skinnier folks also report that this was "too little" sleep more often than the heavier people (63% vs. 9%).

 

In summary, it appears that CR tends to decrease the amount of time people sleep, with people practicing CR for more years, and more severe CR (as measured by BMI) tend to experience a greater decrease, and "early waking" seems to be the most common cause of this sleep reduction.

 

Thanks to everyone who participated!

 

--Dean

Edited September 22, 2015 by Dean Pomerleau

[BrianMDelaney]

Thanks, Dean. Sounds like many of us have early waking sleep reduction, and, for many, this is a problem.

 

- Brian

[Dean Pomerleau]

Thanks, Dean. Sounds like many of us have early waking sleep reduction, and, for many, this is a problem.

 

- Brian

 

Yes, that is a pretty good summary. I forgot to include the "essay responses" to the question about what factors influence their sleep either positively or negatively since starting CR. Below are those responses. Perhaps people can get some tips or tricks to try if they are having trouble sleeping. Also, this thread discusses the likely role elevated cortisol plays in early waking insomnia, and how to potentially deal with it.

 

--Dean

 

-------------------

I can't fall asleep unless I read something - anything - before sleep.

 

Eating less on a given day causes worse early waking.

 

late night coffee drink, watching youtube music videos

 

Fasting impairs, a small snack, stretching, and abstaining from screens improves

 

I listen to great courses from Audible. I end up learning a lot/going back to sleep.

 

I sleepwalk , and when i dream a lot I wake up tired

 

I've found no way to change this pattern. It would be more efficient to get all 8 hours in one block, but that's not how it goes with me. The cat naps are necessary and compensate for the sub-optimal sleeping pattern.

 

Most of my life I have needed eight hours. Now at age 73 it seems closer to nine hours, but I think that has more to do with age than CR. I sleep on a pretty clearly defined 1.5 hour sleep cycle. So I tend to wake up after 6 and 7.5 hours, and do not always find it easy to get back to sleep. And 7.5 is definitely not enough for me on a long term basis. To get back to sleep I spend about 20 minutes running through an analysis I did years ago of a small plane crash in which a business associate (I am convinced) committed suicide (along with killing the passenger in the plane, his girl friend at the time). I don't often get to the end of the analysis!

 

Not going to bed at regular time. Eating late, too much and fat or protein animal foods, especially later int the day.

 

sleep is fantastic but wake early, proportionally to how severely I restrict calories

 

I have always been quick to fall asleep and sleep soundly. Sometimes, I feel "itchy" and take a shower and if necessary an ibuprofen.

 

I need to get up to urinate at least once a night, and generally twice, which actually rather makes the "sleep difficulties" question tricky: I'm sure that the wakeups are not optimal for sleep, but I fall quickly back asleep afterward >80% of the time and it's hard for me to really think of this as a 'sleep difficulty.' I used to be an insomniac, largely cured by CR and good sleep hygeine. The effects of CR on circadian rhythm are reinforced by my habit of eating at the same times every day, each of which entrains circadian rhythm in animal experiments; neither of these were taken up with the intention of dealing with my insomnia, but they did. Additional practices: tryptophan supplement and hot tea with bed; low-dose melatonin twice/week or when switching time zones; earplugs and sleep mask; making sure my feet are warm.

 

need to urinate

 

I wake early when I'm most calorie restricted. A snack soon before bed can help, but I rarely do it. I just get up earlier when I wake early and can't get back to sleep. I seem to function well on less sleep on days after I wake early.

Edited September 28, 2015 by Dean Pomerleau

[Dean Pomerleau]

Here is a follow-up on the implications of the sleep survey results.

 

Recall that on average respondents slept about 0.8 hr less since starting CR, and of the three causes of insomnia, early waking was much more commonly reported than the other two, and trouble falling asleep was quite rare. Here were the numbers -  55%, 5% and 20% of respondents said they had trouble with "early waking", "initiating sleep" and "frequent waking", respectively - see graph in first post in thread.

 

So how much should we worry about losing sleep, particularly due to early waking?

 

Al Pater pointed to a paper with some helpful information (thanks Al!). In this study [1], researchers used data collected via questionnaires about the sleep habits and other health/lifestyle factors from two scandinavian cohorts (from Norway and Finland) of approximately 6000 men and women each, with ages at baseline ranging from 40-60 years in the first cohort and 40-45 years in the second. Then they followed them for an average of about 14 years to see how many died, and how deaths related to their sleep patterns.

 

In particular, they focused on which (if any) of the three types of insomnia was associated with increased mortality during the follow-up period. What they found was interesting, and comforting for us early wakers. Here it is expressed in two tables, one for each cohort, with the most relevant conditions highlighted for reading convenience (click to enlarge):

 

 

 

As you can see, after controlling for the following (self-reported) potential confounders:

 

age, marital status, education, shift work, health behaviour [smoking, alcohol, physical inactivity, obesity (body

mass index > 30 kg m2)], diabetes, cardiovascular diseases, depression, sleep duration and self-rated health.

 

frequent (defined as 3 or more times per week) "trouble initiating sleep" was associated with increased mortality in men only in both cohorts (Cohort1: RR 2.51 (1.07–5.88 95% CI), Cohort2: RR 3.42 (1.03–11.35 95% CI)), but frequent "early waking" was not - the 95% confidence interval spans 1.0 by a wide margin in both cohorts.  Note, they even controlled for sleep duration.

 

The authors didn't investigate cause, but said:

 

As the association among men survived all the adjustments for various health-related factors, such reasons or variation in underlying causes remain open.

 

They also say that from previous studies it appears that only insomnia with "daytime consequences" (presumably things like fatigue and drowsiness) are associated with increased mortality after controlling for all the usual health conditions (diabetes, heart disease, etc.). That extra data collected with one of the cohorts supports this sort of interpretation, namely that "external causes" likely played a role in the increased mortality in men suffering from trouble initiating sleep:

 

n the descriptive analyses in the Finnish cohort,

frequent difficulties initiating sleep were suggested to be

particularly strongly associated with external causes of death

(intoxication/suicide).

 

<snip>

 

The descriptive result in the Finnish cohort regarding the link

between difficulties initiating sleep and external causes of

death is, however, in line with an earlier study (Rodet al., 2014).

 

In addition to "intoxication/suicide", I would presume "accidents" would be another potential "external cause" of mortality that might be elevated in people suffering from daytime consequences of insomnia.

 

One potential caveat I thought of regarding the conclusion that early waking isn't harmful. By controlling for all the usual poor health conditions (e.g. obesity, diabetes, heart disease) as well as depression in their adjusted model, they may have eliminated the causal effect poor sleep (of any kind, including early waking) might have on these conditions, and hence on mortality. But if you look above at the first column of data for men in each cohort, which shows results adjusted only for age, we see the same pattern - namely trouble initiating sleep is associated with (even more) elevated mortality in men in both cohorts (Cohort1: RR 3.88 (1.79–8.42 95% CI), Cohort2: RR 5.80 (2.64–12.76 95% CI)) whereas once again the 95% CI for the "early waking" groups spanned 1.0 by quite a bit.

 

So in summary, early waking, our most frequently reported sleep difficulty, doesn't appear to be associated with elevated mortality, but trouble falling asleep does, at least in men.

 

--Dean

 

------------

[1] Insomnia symptoms and mortality: a register-linked study among women and men from Finland, Norway and Lithuania.

Lallukka T, Podlipskyte A, Sivertsen B, Andruškiene J, Varoneckas G, Lahelma E, Ursin R, Tell GS, Rahkonen O.

J Sleep Res. 2015 Sep 30. doi: 10.1111/jsr.12343. [Epub ahead of print]

Abstract

Evidence on the association between insomnia symptoms and mortality is limited and inconsistent.

This study examined the association between insomnia symptoms and mortality in cohorts from three countries to show common and unique patterns.

The Finnish cohort comprised 6605 employees of the City of Helsinki, aged 40-60 years at baseline in 2000-2002. The Norwegian cohort included 6236 participants from Western Norway, aged 40-45 years at baseline in 1997-1999. The Lithuanian cohort comprised 1602 participants from the City of Palanga, aged 35-74 years at baseline in 2003.

Mortality data were derived from the Statistics Finland and Norwegian Cause of Death Registry until the end of 2012, and from the Lithuanian Regional Mortality Register until the end of 2013. Insomnia symptoms comprised difficulties initiating sleep, nocturnal awakenings, and waking up too early. Covariates were age, marital status, education, smoking, alcohol, physical inactivity, obesity, diabetes, cardiovascular diseases, depression, shift work, sleep duration, and self-rated health. Cox regression analysis was used.

Frequent difficulties initiating sleep were associated with all-cause mortality among men after full adjustments in the Finnish (hazard ratio 2.51; 95% confidence interval 1.07-5.88) and Norwegian (hazard ratio 3.42; 95% confidence interval 1.03-11.35) cohorts. Among women and in Lithuania, insomnia symptoms were not statistically significantly associated with all-cause mortality after adjustments.

In conclusion, difficulties initiating sleep were associated with mortality among Norwegian and Finnish men. Variation and heterogeneity in the association between insomnia symptoms and mortality highlights that further research needs to distinguish between men and women, specific symptoms and national contexts, and focus on more chronic insomnia.

 

PMID: 26420582

[BrianMDelaney]

Wow, thanks to Al for the pointer, and to Dean for the analysis/summary. This is really great news for many of us.

 

- Brian

[Dean Pomerleau]

This popular press article on Marketwatch with the provocative title You Don't Really Need 8 Hours of Sleep is more good news for short sleepers. 

 

It mainly focuses on study [1], which surveyed the sleep habits of three pre-industrial cultures which they suggest are most likely to represent the habits of pre-modern humans. They found "sleep durations of 5.7–7.1 hr, amounts near the low end of [today's] industrial societies". So CR practitioners' relatively short average sleep duration (6.8 hrs) is right in the middle of this 'natural' sleep duration for humans. 

 

--Dean

 

--------

[1] Yetish et al. (2015) Natural Sleep and Its Seasonal Variations in Three Pre-industrial Societies. Current Biology. info:/http://dx.doi.org/10.1016/j.cub.2015.09.046

 

Full text: http://www.cell.com/current-biology/abstract/S0960-9822(15)01157-4

 

Abstract:

 

How did humans sleep before the modern era? Because the tools to measure sleep under natural conditions were developed long after the invention of the electric devices suspected of delaying and reducing sleep, we investigated sleep in three preindustrial societies [ 1–3 ]. We find that all three show similar sleep organization, suggesting that they express core human sleep patterns, most likely characteristic of pre-modern era Homo sapiens. Sleep periods, the times from onset to offset, averaged 6.9–8.5 hr, with sleep durations of 5.7–7.1 hr, amounts near the low end of those industrial societies [ 4–7 ]. There was a difference of nearly 1 hr between summer and winter sleep. Daily variation in sleep duration was strongly linked to time of onset, rather than offset. None of these groups began sleep near sunset, onset occurring, on average, 3.3 hr after sunset. Awakening was usually before sunrise. The sleep period consistently occurred during the nighttime period of falling environmental temperature, was not interrupted by extended periods of waking, and terminated, with vasoconstriction, near the nadir of daily ambient temperature. The daily cycle of temperature change, largely eliminated from modern sleep environments, may be a potent natural regulator of sleep. Light exposure was maximal in the morning and greatly decreased at noon, indicating that all three groups seek shade at midday and that light activation of the suprachiasmatic nucleus is maximal in the morning. Napping occurred on <7% of days in winter and <22% of days in summer. Mimicking aspects of the natural environment might be effective in treating certain modern sleep disorders.

[AlPater]

For the Paleo, Hunter-Gatherer diet philosophers:

 

Science 23 October 2015:
Vol. 350 no. 6259 pp. 360-362
DOI: 10.1126/science.350.6259.360
In Brief
This week's section
By the numbers

6.9–8.5—Average number of hours of sleep per day among hunter-gatherers in three preindustrial societies (Current Biology).

 

 

Natural Sleep and Its Seasonal Variations in Three Pre-industrial Societies.
Yetish G, Kaplan H, Gurven M, Wood B, Pontzer H, Manger PR, Wilson C, McGregor R, Siegel JM.
Curr Biol. 2015 Oct 13. pii: S0960-9822(15)01157-4. doi: 10.1016/j.cub.2015.09.046. [Epub ahead of print]
PMID: 2648084
http://www.cell.com/current-biology/fulltext/S0960-9822(15)01157-4
http://www.cell.com/cms/attachment/2038718285/2052649840/mmc1.pdf

 

Abstract

 

How did humans sleep before the modern era? Because the tools to measure sleep under natural conditions were developed long after the invention of the electric devices suspected of delaying and reducing sleep, we investigated sleep in three preindustrial societies [1-3]. We find that all three show similar sleep organization, suggesting that they express core human sleep patterns, most likely characteristic of pre-modern era Homo sapiens. Sleep periods, the times from onset to offset, averaged 6.9-8.5 hr, with sleep durations of 5.7-7.1 hr, amounts near the low end of those industrial societies [4-7]. There was a difference of nearly 1 hr between summer and winter sleep. Daily variation in sleep duration was strongly linked to time of onset, rather than offset. None of these groups began sleep near sunset, onset occurring, on average, 3.3 hr after sunset. Awakening was usually before sunrise. The sleep period consistently occurred during the nighttime period of falling environmental temperature, was not interrupted by extended periods of waking, and terminated, with vasoconstriction, near the nadir of daily ambient temperature. The daily cycle of temperature change, largely eliminated from modern sleep environments, may be a potent natural regulator of sleep. Light exposure was maximal in the morning and greatly decreased at noon, indicating that all three groups seek shade at midday and that light activation of the suprachiasmatic nucleus is maximal in the morning. Napping occurred on <7% of days in winter and <22% of days in summer. Mimicking aspects of the natural environment might be effective in treating certain modern sleep disorders.

 

[AlPater]

So here is another sleep survey for comparison.  I like going the bed early, am an early bird and like going to bed and rising with the sun and did so when I was alone.

 

I guess I would worry more about middle aged sleep-deprived men flying rather than driving airplanes.

 

 

http://www.cbc.ca/news/health/sleep-1.3570028

 

How sleep patterns differ by sex, age and country revealed by app

Middle-aged men get the least sleep, which could make them risky behind the wheel

CBC News Posted: May 06, 2016 2:00 PM ET Last Updated: May 06, 2016 3:03 PM ET

 

Commuters in Tokyo often nap on the subway because they're so sleep deprived, says a Japanese doctor and sleep expert.

   (Philippe Lopez/AFP/Getty)

 

Smartphone app data hint at how societal pressures to sacrifice sleep contribute to a "global sleep crisis," a new study suggests.

 

Researchers created a free, no-ad app to fight jetlag, and asked people aged 15 and older to send them a treasure trove of anonymous sleep, wake-up and lighting data. Now the mathematicians and computational medicine experts have explored how cultural pressures can override our natural circadian rhythms at bedtime.

 

"It is middle-aged men that seem to be getting a remarkably little amount of sleep, and we think that is very significant," the study's lead author, math Prof. Daniel Forger of the University of Michigan in Ann Arbor, said in an interview. "They are behind the wheel driving trucks, driving airplanes and when they do it with so little sleep, that can pose risks to themselves and also to society."

 

In Friday's issue of the journal Science Advances, Forger and colleagues Olivia Walch and Amy Cochran analyzed data from about 6,000 people in more than 100 countries. Their findings included:

 

Middle-aged men often get less than the recommended seven to eight hours of shut-eye.

 

Women schedule about 30 more minutes of sleep on average by going to bed earlier and waking up later.

 

Age is the main driver of sleep timing. Sleep schedules were more similar among those 55 and older than those younger than 30. As people get closer to retirement, the researchers suspect our bodies will only let us sleep at certain times of the day, Forger said.

 

"If you have very little sleep, you can perform just as well as when you are drunk, so not getting much sleep is indeed a global crisis right now," he said, based on previous studies.

 

What's "normal" for one country differs, the researchers found. The data showed Canadians tend to wake up after 7 a.m., a sleep pattern more similar to those in Britain than in the U.S., Forger said. For total sleep time, Canadians averaged more than 7.9 hours. 

 

'Bad habits' blamed

 

Jason Coulls of Toronto said he averages six hours a night, but would ideally like seven to 7.5 hours.

 

"Between kids, bad habits such as staying up on the iPad, looking at Facebook too much, all those types of things," he said of why he doesn't get the amount of sleep he wants.

 

Carol LeFleur said she mostly gets enough sleep, about seven hours. "I try as much as possible to get enough sleep so I can go through the day without feeling stressed out."

 

Pat Hastings said she tends to get eight hours a day, but sometimes has trouble getting to sleep or waking up in the middle of the night.

 

Not sleeping well can affect what she does the next day, such as trying to catch up on sleep as a passenger. "My husband drives [us] down to the subway station and I get to sleep."

 

The researchers found the Dutch reported the most sleep at about 8.1 hours.

 

Those in Japan and Singapore reported the least hours of sleep, about 7.5 hours. 

 

In Japan, subway commuters often sleep on the train and feel safe doing so, said Dr. Jun Kohyama, a CEO of Tokyo Bay Urayasu/Ichikawa Medical Center and an expert on sleep.

 

"They have to nap because they are very, very sleep deprived," Kohyama said.

 

Japanese people may be irritable from lack of sleep, and workers often retire early because of depression and mood disorders, he said.

 

"Sleep loss leads to a decrease in function of the brain's prefrontal cortex," which is responsible for logical thinking, Kohyama said. He speculates that the effects of lack of sleep on logical thinking could then spiral into an inability to change lifestyle.

 

The study's authors plan to release a version of the Entrain app to collect sleep quality data as well so they can further explore why people sleep differently.

 

While sleep labs remain the gold standard in research, Forger estimates it would have cost more than $200 million U.S. to do the same experiment that way compared with almost no cost to develop the app.  

 

 

A global quantification of “normal” sleep schedules using smartphone data

Olivia J. Walch1, Amy Cochran1 and Daniel B. Forger1,2,*

Science Advances  06 May 2016:

Vol. 2, no. 5, e1501705

DOI: 10.1126/sciadv.1501705

http://advances.sciencemag.org/content/2/5/e1501705.full

http://advances.sciencemag.org/content/2/5/e1501705.full.pdf+html

 

Abstract

 

The influence of the circadian clock on sleep scheduling has been studied extensively in the laboratory; however, the effects of society on sleep remain largely unquantified. We show how a smartphone app that we have developed, ENTRAIN, accurately collects data on sleep habits around the world. Through mathematical modeling and statistics, we find that social pressures weaken and/or conceal biological drives in the evening, leading individuals to delay their bedtime and shorten their sleep. A country’s average bedtime, but not average wake time, predicts sleep duration. We further show that mathematical models based on controlled laboratory experiments predict qualitative trends in sunrise, sunset, and light level; however, these effects are attenuated in the real world around bedtime. Additionally, we find that women schedule more sleep than men and that users reporting that they are typically exposed to outdoor light go to sleep earlier and sleep more than those reporting indoor light. Finally, we find that age is the primary determinant of sleep timing, and that age plays an important role in the variability of population-level sleep habits. This work better defines and personalizes “normal” sleep, produces hypotheses for future testing in the laboratory, and suggests important ways to counteract the global sleep crisis.

 

Keywords

 

smart phones

 

sleep

 

sleep schedules

[Dean Pomerleau]

All,

 

Here is an article on why naps are so good for you, the cool infographic included below. I was particularly struck  by the mention of a study that found a 30min nap 3x per week resulted in a 37% lower heart disease mortality.

 

It also mentions 26 minutes as the optimal nap duration according to some recent research. It's funny, that is exactly how long I set the timer for my daily nap, although just prior to my nap I do 6 minutes of inversion therapy, during which I also tend to nod off. I also do the pre-nap caffeine thing the infographic talks about, which I find works pretty well.

 

--Dean

 

[AlPater]

Funny thing about that, the first Pubmed search article was:

 

http://www.journalsleep.org.sci-hub.cc/ViewAbstract.aspx?pid=30338

 

from which Figure 5 informs.

[Pablo Stafforini]

Dean (and others),

 

A recent meta-analysis of prospective cohort studies found a positive association between daytime napping and all-cause mortality.

 

Note, incidentally, that the interesting study of sleep in three pre-industrial societies you discuss above mentions that napping is relatively rare in such societies.

 

--

 

Daytime napping and mortality from all causes, cardiovascular disease, and cancer: a meta-analysis of prospective cohort studies [pdf]

Zhong, Guochao et al.

Sleep Medicine , Volume 16 , Issue 7 , 811 - 819

 

Abstract

Objectives

The association between daytime napping and mortality remains controversial. We conducted a meta-analysis to examine the associations between daytime napping and the risks of death from all causes, cardiovascular disease (CVD), and cancer.

 

Methods

PubMed and Embase databases were searched through 19 September 2014. Prospective cohort studies that provided risk estimates of daytime napping and mortality were eligible for our meta-analysis. Two investigators independently performed study screening and data extraction. A random-effects model was used to estimate the combined effect size. Subgroup analyses were conducted to identify potential effect modifiers.

 

Results

Twelve studies, involving 130,068 subjects, 49,791 nappers, and 19,059 deaths, were included. Our meta-analysis showed that daytime napping was associated with an increased risk of death from all causes [n = 9 studies; hazard ratio (HR), 1.22; 95% confidence interval (CI), 1.14–1.31; I2 = 42.5%]. No significant associations between daytime napping and the risks of death from CVD (n = 6 studies; HR, 1.20; 95% CI, 0.96–1.50; I2 = 75.0%) and cancer (n = 4 studies; HR, 1.07; 95% CI, 0.99–1.15; I2 = 8.9%) were found. There were no significant differences in risks of all-cause and CVD mortality between subgroups stratified by the prevalence of napping, follow-up duration, outcome assessment, age, and sex.

 

Conclusions

Daytime napping is a predictor of increased all-cause mortality but not of CVD and cancer mortality. However, our findings should be treated with caution because of limited numbers of included studies and potential biases.

Edited November 26, 2016 by Pablo Stafforini

[Gordo]

I think you'd have to have at least a 10 year "look back" period for such an analysis to make sense (avoid preexisting conditions).  But beyond that, you'd want to look at the reasons the people were napping - in most cases I'm guessing its because they had lousy sleep the night before, which could be caused by any number of life shortening factors such as stress, anxiety, sleep apnea, poor diet, chronic pain, etc.  There just aren't many people who both have the ability to, and make the conscious decision to do usual sleep routines like 6 hours at night and 1 hour in the afternoon even though segmented sleep used to be the norm.

[KHashmi317]

Was too late for this survey, but better late than never...

 

I'm 49yo, and 118lbs.

 

After practicing pretty heavy CR for nearly 17 years, I can say that stress, circumstances and commitments are much more important to quality/qty of sleep than CR alone, tho' I'd probably avg. an hour or so more w/o CR.

Also, acute over-exercise (longer bike ride) or acute energy-intensive errands (help a friend move), also disturbs sleep.

 

All that said, sleep for me,  over 24hrs, is 6-7hrs total. I do this in three segments; this is "timed" with meals. What I've come to know is that with heavy CR (esp. at v. low BF), there are drowsiness windows formed about 30min  after finishing meals. And I just go with the flow.

Yeah, eating this close to sleep time can cause issues with needing to urinate sometime during the sleep cycle.

A "bedpan" can keep help keep one in "sleep momentum", allowing one to re-sleep quickly.

 

 

-Khurram

Edited December 8, 2016 by KHashmi317

[Saul]

Nice hearing from you, Khurram!

Give my best to Warren.

(The last time I spoke to Warren, he thought that you were anorexic.)

:)

-- Saul

[AlPater]

Me, I have been napping ~20-30 minutes almost every afternoon after my ~hour afternoon walk; sleeping about 6.5 hours at night.

 

Association of napping and all-cause mortality and incident cardiovascular diseases: a dose-response meta analysis of cohort studies.
Pan Z, Huang M, Huang J, Yao Z, Lin Z.
Sleep Med. 2020 Aug 10;74:165-172. doi: 10.1016/j.sleep.2020.08.009. Online ahead of print.
PMID: 32858276 Review.
https://sci-hub.tw/10.1016/j.sleep.2020.08.009
Abstract
Background: Napping is a habit prevalent worldwide and occurs from an early age. However, the association between napping and the risk of incident cardiovascular disease (CVD) and all-cause mortality remains unclear.
Methods: We conducted a systematic search of Medline, Embase, and Cochrane databases from inception to December 2019 for cohort studies investigating the association between napping and the risk of incident CVD and/or all-cause mortality. Overall estimates were calculated using random-effect models with inverse variance weighting. Dose-response meta-analysis was performed using restricted cubic spline models.
Results: A total of 313,651 participants (57.8% female, 38.9% took naps) from 20 cohort studies were included in the analysis. All-cause mortality was associated with napping overall (HR 1.19, 95% CI 1.12-1.26). Pooled analysis detected no association between daytime nap and incident CVD. However, in subgroup analysis including only participants who were female (HR 1.31, 95% CI 1.09-1.58), older (HR 1.36, 95% CI 1.07-1.72), or took a long nap (HR 1.34, 95% CI 1.05-1.63), napping was significantly associated with a higher risk of CVD. Dose-response analysis showed a J-curve relation between nap time and incident CVD. The HR decreased from 0 to 25 min/day, followed by a sharp increase in the risk at longer times. A positive linear relationship between nap time and all-cause mortality was also observed.
Conclusions: Long napping was associated with increased risks of incident CVD and all-cause mortality. Further, large-scale studies and genetic studies need to confirm our conclusion and investigate the underlying mechanisms driving these associations.
Keywords: All-cause mortality; Cardiovascular disease; Dose–response meta-analysis; Nap.

Edited August 30, 2020 by AlPater