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\
arrizzo@cbnewsl.att.com (anthony.r.rizzo) (07/14/90)
In article <58173@bbn.BBN.COM< cosell@bbn.com (Bernie Cosell) writes: <arrizzo@cbnewsl.att.com (anthony.r.rizzo) writes: < <}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. < < /Bernie\ It seems, then, that you're supporting my conjecture. It's easy to imagine how an individual in a primitive environment might become prey if his body cycle were "out of sync." I had one very poor teacher for linear control systems, when I was in engineering school. So I'll take you at your word that the longer cycle stays in sync and the shorter one doesn't. And, actually, it's easy to see why. But I never would have thought of it. Nevertheless, the final result of an out-of-sync cycle must have been an early death, during a time when men and women had little more than two legs for protection. Evolution, I've been told, works in a conservative way. For example, the ancient fish whose fins eventually resembled legs and who gradually became amphibians were the subset that survived being washed ashore by wriggling their way back to the water, the superset being all those that were washed ashore. Similarly, I suggest, the individuals whose body cycles were longer than 24 hr (for whatever reason) were the subset that survived long enough to have offspring. Therefore, we now have body cycles longer than 24 hr. -- ----------------------------------- tony -----------------------------------
starkid@ddsw1.MCS.COM (Lance Sanders) (07/15/90)
On 2 Jul 90 03:20:43 GMT, tmca@ut-emx.UUCP (The Anarch), in Message-ID: <33843@ut-emx.UUCP> writes: >'m told, through various reputable sources, which I can't remember >ust this minute, that the majority of the human race lives on a 25 hr >chedule, and some on as long as a 27 hr schedule. By schedule, I mean >circadian (sp?) rhythms and such like. Researchers at the Max Planck Institute for Psychiatry in Munich, Germany (Jurgen Zulley and Scott Campbell), who isolated subjects in an underground bunker with no way to judge time outside of their environment (and with no music, writing, reading, alcohol, coffee or tea) found in 1987 that there were four-hour rhythms---periods of increased readiness to sleep---in addition to night sleep. Daytime sleeping occurred most often at 1 p.m., but shorter naps also took place at 9 a.m. and 5 p.m. Those in midday sleep for more than 90 minutes had deeper sleeps, followed by periods of dreaming. Richard E. Kronauer, professor of mechanical engineering at Harvard, found that people chose map times at 5:30 p.m., slept for three hours, stayed up for eight hours and slept another four hours. In essence, their days were split in half. Thomas Wehr, chief of the clinical psychobiology branch of the National Institute of Mental Health, believes data indicates that the natural sleep pattern is a couple of hours in the daytime and five hours at night. Humans appear to be genetically programmed to nap. Psychologist Scott S. Campbell of the Institute for Circadian Physiology in Boston (formerly at the U. of California at San Diego), along with Irene Tobler, discovered napping behavior in 160 different species of animals, from insects to primates. All creatures except humans (due to cultural and industrialization factors) break up sleep into several discreet phases per day, or doze lightly while doing something else. Campbell believes that "we go against nature when we sleep just once in twenty-four hours". Enforced night sleep disrupts the natural tendency toward nodding off during the height of the day. Research indicates that reactions to allergens and many disease states are strongly linked to internal circadian rhythms. Asthma occurs more often at night than during the day, not only because there is more pollen or dust in the air in the evening, but because of fluctuations in immune system defenses. The threshold for pain is lower at night than it is in the afternoon. Migraine and muscle headaches usually begin in the early hours of the morning. the onset of fever from a viral infection occurs mainly during the late afternoon and evening, between 2 and 10 p.m. Onset of fever from bacterial infection occurs aminly during the morning, between 5 a.m. and noon. White blood cells, which play a large role in the immune response, are more active during the evening than at night, etc. Since the small proteins that enhance immune function are also sleep-inducers, is the built-in tendency to nap associated with general immune system enhancement; modification of hypertension? Are the four-hour rhythms/periods of increased tendency to sleep associated with pulses in increased immune system efficiency? It would appear so. The muramyl peptides are associated with deep, slow-wave sleep. David Dinges, a sleep researcher at the U. of Pennsylvania, has determined that during naps, most sleep is in the depest stages, characterized by slow, regular brain waves. Relatively little of a nap is spent in the phase of sleep during which most dreaming occurs. A study by the U. of Athens Medical School looked at Greeks, half of whom nap, half who don't. They compared men hospitalized for coronary heart disease with men hospitalized for other reasons and concluded that Greek men who nap half an hour or more every day are 30 percent less likely to develop a cardiac condition than those who don't nap. [[ It's a widespread custom in Japan to allow night-shift workers to have naps to break up their time on the job. ]] Most afternoon naps are between 30 and 90 minutes. Naps under 15 minutes are uncommon. Naps of just a few minutes reach only the first stage of sleep. Slow-wave sleep doesn't occur until later in the cycle. Psychiatrist Martin Orne of the U. of Pennsylvania and Institute of penn. Hospital notes that napping should be practised "prophylactically" (!). "Nap *before* you're tired." On the average, naps begin about 12 hours after the middle of the main period of sleep. Someone who slept from midnight to 6 a.m. would be most highly primed for a nap around 3 p.m. Dr. William Dement, director of the Sleep Disorders Clinic and Research Center at Stanford University, in a preface to 'Sleep and Alertness: Chronobiological, Behavioral and Medical Aspects of Napping (Raven Press)': "It seems nature definitely intended that adults should nap in the middle of the day; the body has an inherent need to nap." --------- Lance Sanders starkid@ddsw1.MCS.COM Bo knows psychoneuroimmunology. GEnie: L.Sanders6 Voice: (312)667-5958
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
wcalvin@milton.u.washington.edu (William Calvin) (07/18/90)
>Paul Johnson asks, so what has 25 hours between tides got to do with it?
Well. we are evolved from animals that used to make their living in the
intertidal (that was that stage in the evolution of land animals where
an ancestors learned to get along up in the air for hours at a time).
The rhythms of that life style are more like 25 hours than 24, as the
food is swept along by 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 206/543-1648chrish@videovax.tv.tek.com (h) (07/20/90)
If the 25hr day needed to be longer than the 24hr earth cycle so that the sync pulse of the sunrise/sunset would be short enough to act as the necessary positive feedback mechanism why wouldn't it vary with the seasons? The sync pulses of sunset/sunrise come so much closer together in winter than in summer. If the conjecture is that man needed to stay awake longer for awareness of nocturnal predators, the same question applies. Why wouldn't it vary with the seasons?