Monday, January 01, 2007

A Dream Wrapped in an Enigma

For many, I suspect sleep is one of those things so taken for granted that its "why" question simply never arises. Certainly, that has been true for me.

However, in a matter of a couple days, several items came flying across the transom:

-- Apparently, the best thing about the holidays is taking a nap

-- Followed closely by the begged, but rarely asked, question: Why do we need sleep?

-- Which was separated by mere column inches in a multi-part article having nothing to do with sleep from Shortening Sleep will Prolong Conscious Life

-- Overlaying all of this is a recent, very sudden, change in my sleep patterns, from an average of six hours per day to four.

As for the first, I am agnostic. For a sleep believer, naps are an essential part of life whose absence is nearly beyond comprehension. For the rest of us, naps are beyond attainment.

As for the "why" question, surprisingly, the answer is, given the near totality of our knowledge regarding other bodily functions, nine parts out of ten "dunno." Saying one needs sleep to go from tired to rested is certainly true, but only succeeds in changing the question's wording, rather than providing any sort of answer.

Even noting that the consequences for rats of long term sleep deprivation was uniformly fatal only undergirds the obvious: yes, we need sleep. Yet the "why" question remains untouched.

Biologists have long known that, for mammals, at least, metabolic rates are inversely proportional, and lifespans are directly proportional, to body mass. Consequently, on average, elephants and mice have the same number of heartbeats in a lifetime, despite the wildly divergent pulse rates.

Yet this relationship is completely inverted with respect to sleep. Mice sleep far longer per day than elephants. As it turns out, the brain, not body, mass ratio between the two is the constant of proportionality; this points to brain maintenance as the reason for sleep.

This stills leaves "why" dangling, but the question now at least has a very accusatory finger.

For sleepists, sleep is a positive luxury; for asleepists, it is simply a necessary evil. After all, one way to extend our lifetimes, particularly in our prime, without living any longer is simply to sleep a heck of a lot less. If we could accomplish the restorative functions of sleep in a quarter of the time, should we? If we could modify the genes governing sleep rate, would the consequent surge in human productivity be a good thing, or just another dangerous example of playing at God?

Here there is good news. Fruit flies, those hardy laboratory perennials, have sleep patterns similar to humans. Like the hox gene, this indicates that, for whatever reason, evolution strongly conserves sleep regulation across the animal kingdom. As it turns out, a gene called Shaker, when mutated in a specific way, reduces daily sleep from 12 hours to 4, without any apparent effect on the flies' well being.

Well, except for very truncated lifespans. That would seem to count as bad news.

As for me, if big pharma was to come up with a pill that would cause the effects of six hours sleep to obtain in two, I would be making an appointment to see my doctor.

"Hey, about those side effects ...?"

10 Comments:

Anonymous Anonymous said...

Another sleep factoid to add to the pile.

January 01, 2007 8:51 AM  
Blogger Harry Eagar said...

The fact that Skipper can fly airplanes on six hours/day of sleep, while I cannot even write headlines on less than 8 hr/day suggests that the error bars are pretty fat.

January 01, 2007 9:21 AM  
Blogger Hey Skipper said...

Harry:

Alternatively, it takes a lot more brain bytes to write a headline than be a glorified heavy equipment operator.

That said, it is apparently true that the sigma for sleeping hours/day across the population is pretty low (i.e., flat bell curve, wide distribution).

January 01, 2007 9:48 AM  
Blogger Bret said...

I was always told that we sleep because otherwise we, not sleeping and being bored, would've wandered outside our caves at night and would've been eaten by saber tooth tigers. Likewise, for those of us from far north climes, we have Seasonal Affective Disorder because that kept us inside in our beds all winter - otherwise we would've wandered outside and frozen to death.

January 01, 2007 10:05 AM  
Blogger Peter Burnet said...

Bret:

Apparently among the Inuit old-timers it was quite common for them to sleep three solid days in winter and stay awake for the same amount of time in summer.

It would be neat to do an international or inter-cultural poll to see who would agree with Skipper that a pill permitting less sleep would be a boon. I'd bet a lot Americans would come out far ahead of the pack on the positive side, although maybe the Japanese would be there too.

January 01, 2007 10:37 AM  
Blogger Oroborous said...

I like sleeping, but I'd sleep less, if I could do so without harm or lowered quality of life. In the past, during periods when, for various reasons, I was getting less than 4 hrs. a night for weeks on end, I was mentally dull and had less stamina physically.

Regarding the Althouse link - "..about how the natural sleep pattern is to have a first and second sleep, with a wakeful period in between" - I don't find that to be true. Whenever I can sleep freely, without scheduling, I don't have a 24 hr. wake-sleep cycle, (more like 28), and I sleep soundly for one long period.

January 01, 2007 10:50 AM  
Blogger Harry Eagar said...

Never heard that about the Inuit, but reputedly the peasants in the northernmost grain-growing districts of Russia would have to work virtually around the clock for six weeks to get their fields prepared and seeded in time to allow a sufficient growing season.

This after spending much of the winter lying around on the stove.

January 01, 2007 3:16 PM  
Blogger Hey Skipper said...

I have become a Circadian lab rat.

E.g: At the end of my last trip in Jan, I will leave Shanghai at 5pm, land for a couple hours in Seoul, then takeoff for Anchorage at 9pm, arriving at 11pm the previous morning (its a dateline thing). Then an hour and a half later, I'll jumpseat to Indianapolis, landing at midnight, than hang until four am, before getting another jumpseat to Detroit, landing at 5:30am. The drive puts me home at 6:30.

By the time I get to bed that night, I'll have been up for something like 36 hours (perhaps this is a comforting sign -- I haven't yet mastered sleeping on a plane).

Each time I've done this, I get the eerie feeling I've gone beyond sleep; where exhaustion should be, there is nothing.

Then I think about the sleep deprived lab rats.

Thank goodness for Ambien CR.

January 02, 2007 4:35 AM  
Blogger Duck said...

Skipper,
Are the rules about how long you can go without sleep different than they are for passenger airline pilots? Just curious.

January 02, 2007 3:06 PM  
Blogger Hey Skipper said...

Duck:

They are the same. Maximum 8 hours continuously at the controls, 16 hour maximum crew duty day, minimum 9 hour rest period between duty days.

For any leg longer than 8 hours (including ground ops), we have to carry a relief pilot; once at altitude he alternates with the the other two pilots to provide the required rest period.

If a leg is long enough -- e.g., Paris to Manila (~13 hours), then we carry a relief crew, who takes the middle 8 hours of the flight.

January 03, 2007 6:14 AM  

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