tmca@ut-emx.UUCP (The Anarch) (07/12/90)
OK, I gotta question: I'm told, through various reputable sources, which I can't remember just this minute, that the majority of the human race lives on a 25 hr schedule, and some on as long as a 27 hr schedule. By schedule, I mean circadian (sp?) rythms and such like. Now this is all very well, and would explain admirably why I can't get up of a morning, but, being a scientist 'n'all, I can't help but think that there ought to be some good reason for this. After all, the Earth has been running on a 24 hr day for quite some time now, and I'd've thought that we'd have caught up by now. Anyone got any ideas? On a related note, being an astronomer, I'm often faced with the transition from a day schedule to a night schedule and back again. Some years of practise have led me to the conclusion that I can only grin and bear it. Anyone got any better, more scientific ideas of how to deal with jet-lag? Tim -- Tim Abbott | "out there in the darkness, out there in the night Astronomy, UTexas Austin | out there in the starlight, one soul burns tmca@astro.as.utexas.edu | brighter than a thousand suns." - Simple Minds
wcalvin@milton.u.washington.edu (William Calvin) (07/12/90)
The free-wheeling sleep-wakefulness pattern for many humans deprived
of "zeitgeibers" (sync signals) is indeed about 25 hours. See
articles in Scientific American and such.
The Earth may rotate at 24 hours between sunrises, but the
time between moonrises is more like 25 hours -- and thus the time
between low tides and the major tidal currents.
William H. Calvin
Univ. of Washington wcalvin@well.sf.ca.us
Biology NJ-15 wcalvin@u.washington.edu
Seattle WA 98195 206/328-1192 206/543-1648wcalvin@milton.u.washington.edu (William Calvin) (07/12/90)
Also, you asked about resetting your internal clock. Big news in that
area is that strong sunlight at the desired hour of awakening can
reset the internal clock in just 48-72hours.
My own formula is 1) avoid alcohol before and during the
changeover; 2) don't turn the lights on if you can't sleep and
just read (allowing melatonin to be secreted from the pineal is
probably important as a master hormone in this area, and it
requires darkness); and 3) get up at the desired hour and go for
a walk (if daylight) or otherwise find very bright lighting for
the first two hours (if an astronomer).
William H. Calvin
Univ. of Washington wcalvin@well.sf.ca.us
Biology NJ-15 wcalvin@u.washington.edu
Seattle WA 98195 206/328-1192 206/543-1648swsh@midway.uchicago.edu (Janet M. Swisher) (07/13/90)
In article <4983@milton.u.washington.edu> wcalvin@milton.u.washington.edu (William Calvin) writes: >Also, you asked about resetting your internal clock. Big news in that >area is that strong sunlight at the desired hour of awakening can >reset the internal clock in just 48-72hours. > My own formula is 1) avoid alcohol before and during the >changeover; 2) don't turn the lights on if you can't sleep and >just read (allowing melatonin to be secreted from the pineal is >probably important as a master hormone in this area, and it >requires darkness); and 3) get up at the desired hour and go for >a walk (if daylight) or otherwise find very bright lighting for >the first two hours (if an astronomer). Once upon a time, I heard about some research on sleep-cycle shifting that was done at Argonne National Labs. Among their findings was that for most people, it's easier to shift by sleeping later and later than by getting up earlier and earlier (confirming the suspicions of all the owl-people in the world :-). Thus they recommend that employers who rotate employees' shifts rotate day-> evening->night rather than the other direction. They also developed the Argonne Anti-Jet Lag Diet, which can be used by anyone shifting their sleep cycle. However, it requires knowing three days in advance that you are going to make the shift. It involves alternating "feast" and "fast" days, making the shift on the second "fast" day. "Feasting" means eating lots of high-carbohydrate foods like meats and starches; "fasting" means avoiding those foods, and sticking to things like fruits and vegetables. You also should avoid alcohol or caffeine on the day of the switch. Some where in my files at home I have a wallet-sized card that summarizes the whole thing. If there's sufficient interest, I could find it and post the details. I've never actually used the Anti-Jet Lag Diet, since I've never been lucky enough to travel across many time zones at once, or unlucky enough to work swing shifts. Janet Swisher swsh@midway.uchicago.edu I speak for myself.
wcalvin@milton.u.washington.edu (William Calvin) (07/13/90)
A good article on sleep rhythms is Mary Gribbin, "All in a night's sleep," New Scientist (7 July 1990). Further reading: J. Allan Hobson, _Sleep_ (Scientific American Books). Ian Oswald, _Sleep_ (Penguin) William Dement, _Some Must Watch While Some Must Sleep_ (Freeman). Ray Meddis, _The Sleep Instinct_ (Routledge & Kegan Paul) James Horne, _Why We Sleep_ (Oxford UP) J. Allan Hobson, _The Dreaming Brain_ (Basic Books 1988). William H. Calvin Univ. of Washington wcalvin@well.sf.ca.us Biology NJ-15 wcalvin@u.washington.edu Seattle WA 98195 206/328-1192 206/543-1648
arrizzo@cbnewsl.att.com (anthony.r.rizzo) (07/13/90)
In article <33843@ut-emx.UUCP> tmca@emx.UUCP (The Anarch) writes:
#OK, I gotta question:
#
# I'm told, through various reputable sources, which I can't remember
#just this minute, that the majority of the human race lives on a 25 hr
#schedule, and some on as long as a 27 hr schedule. By schedule, I mean
#circadian (sp?) rythms and such like. Now this is all very well, and would
#explain admirably why I can't get up of a morning, but, being a scientist
#'n'all, I can't help but think that there ought to be some good reason
#for this. After all, the Earth has been running on a 24 hr day for quite
#some time now, and I'd've thought that we'd have caught up by now. Anyone
#got any ideas?
#
# On a related note, being an astronomer, I'm often faced with the
#transition from a day schedule to a night schedule and back again. Some
#years of practise have led me to the conclusion that I can only grin
#and bear it. Anyone got any better, more scientific ideas of how to
#deal with jet-lag?
#
# Tim
This is a very interesting question. I've heard the same statements
from equally reputable but unmemorable sources.
I agree with you. There must be some good reason for the mismatch,
and it must be evolutionary in nature. Here's my idea:
the 25 hr to 27 hr cycle is observed only in the laboratory.
Individuals eventually reverse their sleep/waking periods
completely if their bodies are not permitted the luxury of
some form of clock or time reference, such as the sun.
However, outside of the laboratory such a time reference
is inevitable. We're usually awakened by sunlight and
animal noises, in the absence of a timepiece. Therefore,
outside of the laboratory, such as in the wild millions
of years ago as well as now, the body's cycle is reset
each morning. I suggest that the longer cycle ensured
a necessary degree of alertness at dusk, when most
predators go hunting. Individuals whose bodies were
on a 24 hr cycle probably became prey and didn't get
the chance to have offspring. Individuals whose bodies
were on a 25 hr (or longer) cycle probably were able
to avoid becoming prey and got a chance to live long
enough to have offspring. What do you think?
--
----------------------------------- tony -----------------------------------cosell@bbn.com (Bernie Cosell) (07/13/90)
arrizzo@cbnewsl.att.com (anthony.r.rizzo) writes: }In article <33843@ut-emx.UUCP> tmca@emx.UUCP (The Anarch) writes: }#OK, I gotta question: }# }# I'm told, through various reputable sources, which I can't remember }#just this minute, that the majority of the human race lives on a 25 hr }#schedule, and some on as long as a 27 hr schedu }#... Now this is all very well, and would }#explain admirably why I can't get up of a morning, but, being a scientist }#'n'all, I can't help but think that there ought to be some good reason }#for this. After all, the Earth has been running on a 24 hr day for quite }#some time now, and I'd've thought that we'd have caught up by now. Anyone }#got any ideas? }I agree with you. There must be some good reason for the mismatch, }and it must be evolutionary in nature. Here's my idea: }the 25 hr to 27 hr cycle is observed only in the laboratory. }Individuals eventually reverse their sleep/waking periods }completely if their bodies are not permitted the luxury of }some form of clock or time reference, such as the sun. }However, outside of the laboratory such a time reference }is inevitable. We're usually awakened by sunlight and }animal noises, in the absence of a timepiece. Therefore, }outside of the laboratory, such as in the wild millions }of years ago as well as now, the body's cycle is reset }each morning. I suggest that the longer cycle ensured }a necessary degree of alertness at dusk, when most }predators go hunting.... Actually, I have a simpler conjecture. Just try to figure out how YOU would design such a cycle. It is obviously important for the body functions to stay in sync with the sun, and so you need some kind of fairly stable cycle. Well, about the simplest mechanism I can think of to do that is to have a simple positive-sync mechanism, and then have the natural cycle be just a bit too long. Thus, the animal would sleep through the night, and the rising of the sun (for diurnal animals) would 'sync' the cycle and start it up. And so you'd have nice feedback and the cycle would stay in sync. What happens if the cycle is too short? Well, your body would start its new day too early, and then an hour or so later the 'sync' would come but what should your body do then? Things have been going already, your body temp has changed, the metabolism sped up, and it is real hard to see how the body would use the hour-late sync [and more importantly, when you wake up ANOTHER hour earlier the next day, the sync comes *two* hours late, and it is hard to see how the feedback would work]. On the other hand, mostly the body is idling through the night and having the sync-pulse kick off the start of that day's rhythms works perfectly --- and all it takes is to have the *natural* cycle be just a bit too long, so that when the sync comes you're still on 'overnight' and _just_ about to kick the new-day systems in. As a meta comment, there were some studies [by the Air Force I think, it was written up in one of those books about how to beat jet lag]. It bascially said that the onset-of-daylight was the *primary* mechanism for regulating the circadian cycles. And so their recommended jet-lag procedure was that prior to your trip you work fairly hard to mess up your rhythms [e.g., you avoid going out in broad daylight, you change your eating habits, etc] The idea is to give you body as little syncing-feedback as you possibly can, and to actually interfere with the cycles as much as you can. This is all orchestrated so that it builds to a climax on the day of your trip: the idea is that while you're on the airplane winging your way to whereever, you want the buildup to have resulted in your body being *totally* confused an de-synced. There won't be much of anything to resync it on the plane, of course. And then you arrive at your destination and the theory is that your bod will almost-instantly sync up to the new cues. Dunno if it works or not --- I never had the patience to follow through with the whole two-week-before-the-trip plan. /Bernie\
werner@aecom.yu.edu (Craig Werner) (07/15/90)
In article <4982@milton.u.washington.edu>, wcalvin@milton.u.washington.edu (William Calvin) writes: > The free-wheeling sleep-wakefulness pattern for many humans deprived > of "zeitgeibers" (sync signals) is indeed about 25 hours. See Most species active during the day have internal cycles that are greater than 24 hours. On the other hand, most nocturnal animals have cycles that are less than 24 hours. Since the molecular basis of any circadian rhythm is not yet known (although taking a clue from electromagnetic radiation, it probably involves two components in a mutual feedback loop) why this should be is currently unanswerable. -- Craig Werner (future MD/PhD, 5.5 years down, 2.5 to go) werner@aecom.YU.EDU -- Albert Einstein College of Medicine (1935-14E Eastchester Rd., Bronx NY 10461, 212-931-2517) "Viruses do to cells what Groucho did to Freedonia."
paj@mrcu (Paul Johnson) (07/17/90)
>The free-wheeling sleep-wakefulness pattern [...] is indeed about 25 >hours. > The Earth may rotate at 24 hours between sunrises, but the >time between moonrises is more like 25 hours -- and thus the time >between low tides and the major tidal currents. OK. So what's that got to do with it? -- Paul Johnson UUCP: <world>!mcvax!ukc!gec-mrc!paj --------------------------------!-------------------------|------------------- GEC-Marconi Research is not | Telex: 995016 GECRES G | Tel: +44 245 73331 responsible for my opinions. | Inet: paj@uk.co.gec-mrc | Fax: +44 245 75244