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Scientists Describe Internal Clocks That Don't Follow Day and Night Cycles 91

sciencehabit writes "Almost all organisms, from bacteria to mammals, have a circadian clock—a mechanism in their cells which keeps them in sync with Earth's day-and-night cycle. But many organisms follow other rhythms as well. Now, new research provides the first evidence that animals have molecular cycles independent of the circadian rhythm. They include a sea louse whose swimming patterns sync up with the tides, and a marine worm that matures and spawns in concert with the phases of the moon. The discoveries suggest that noncircadian clocks might be common and could explain a variety of biological rhythms."
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Scientists Describe Internal Clocks That Don't Follow Day and Night Cycles

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  • Lunar clocks? (Score:5, Interesting)

    by ozmanjusri ( 601766 ) <aussie_bob@@@hotmail...com> on Friday September 27, 2013 @12:52AM (#44967653) Journal
    I wonder if they realise a significant proportion of humanity have internal clocks based on a lunar cycle?
    • by Narcocide ( 102829 ) on Friday September 27, 2013 @12:55AM (#44967661) Homepage

      My internal clock is based on a caffeine cycle.

    • Warewolfs
    • After I retired, it became clear my "natural" cycle was about 26 hours.


      • Re: (Score:2, Interesting)

        by Anonymous Coward

        It's even more annoying whilst in the midst of your career like I am. I have noticed I definitely do not operate on a 24 hour clock either and it is hell. Fortunately for me I telecommute. A few weeks ago I was going to bed at 4pm while waking up around 2am, and day after day it kept getting progressively later until I made my way all around the clock again. For the past few days I've been taking two 4~ hour naps. One around 3pm and one around 3am.

      • Actually, I believe MOST people have a sun-independent rhythm of 24.5-27 hours. When placed in isolation from normal sunrise/sunset, nearly everyone drifts to a longer wake cycle resulting in an extended "day". I can't remember the specific paper I read.

    • Re: (Score:2, Interesting)

      by Anonymous Coward

      Well, "lunacy" is definitely a thing. People freaking out during full moons has happened since the dawn of man.

    • by jdbuz ( 962721 )
      Nope. Well, not unless you're really into surfing. But all that nonsense about hospital rooms visits and the like syncing with lunar cycles has been debunked time and time again. For example: Bad Astronomy [discovermagazine.com] Science Daily [sciencedaily.com]
    • Re:Lunar clocks? (Score:4, Informative)

      by captainpanic ( 1173915 ) on Friday September 27, 2013 @01:35AM (#44967797)

      I think that the female cycle is close to the lunar cycle, but not exactly synchronized with it. It would be similar to people having a 22 hour day cycle instead of 24.

      The menstrual cycle can be anywhere from 25-35 days, with an average of 28 days.
      The lunar cycle is 29.5 days.

      On a sidenote, imagine the horror if all women of the world would have their period exactly synchronized!

      http://en.wikipedia.org/wiki/Menstrual_cycle [wikipedia.org]
      http://en.wikipedia.org/wiki/Lunar_phase#Overview [wikipedia.org]

      • Then we'd have "mating seasons", like many other animals. Maybe the reason they are NOT synchronized is because it was too much of a distraction...
        • Animals that have a mating season, usually have no sex drive outside that season (that accounts for males and females).

          Big difference with humans and certain other primates, where both sexes are always interested in sex.

      • by epine ( 68316 )

        On a sidenote, imagine the horror if all women of the world would have their period exactly synchronized!

        From what I've been reading lately—in recent books—about half of the crabbiness is due to women not eating enough to compensate for their increased metabolic rate during their periods. Men also get crabby when we don't eat enough to replenish our willpower reserves. It takes willpower to make the generous response rather than the first lizard response that enters our brain.

      • by dywolf ( 2673597 )

        Be like The Purge (decent flick), but worse...and more often.
        Actually that'd be a great b or c movie.

        Every 29 days men and children would lock themselves in bunkers while chaos and monsters roam the streets....

    • If you're talking about menstruation, it's a myth that it's linked to the moon.
      • by cusco ( 717999 )

        It can be. I knew several practicing Wiccans who nightly observed the the moon phases (well, as 'nightly' as one can get in Seattle). After a couple of months their cycles somehow got synched to around the time of the full moon, and stayed that way until I moved out of town and lost contact with them a year or so later. None were on any artificial birth control and all were vegetarians or almost-vegetarians who cooked almost everything at home. A couple of them lived in the same house for a time (women

    • Conclusion is a bit odd. As if it'd be a surprise.

      First that comes to mind is indeed the human female menstual cycle.

      Another is the yearly breeding cycle in most other animals, where they follow some yearly cycle (though that may not be a biological clock indeed).

      I also wonder how animals that live their life underground, or in the deep sea (no sunlight) do. Do they also have a "day" rhythm, for example?

    • If "they" are men, they know very well that half of humanity is running on a lunar cycle...
    • I have kept charts on my sleep schedule for years being as there is absolutely no circadian rhythm to it at all. There is no pattern, at least not that I can find. When I was in school and working I had to be up in the morning despite only having a few hours - or none - of sleep. Now that I am retired the whole day/night thing has just disappeared completely. Sometimes I won't sleep for 30 hours, sometimes 2, sometimes 12. I have read several books on sleep and took one of those TTC courses on it but have
    • That is not true, women's cycle is disrupted by lack of light etc. Women living underground without sunlight mess up their sleep cycle and their menstrual cycle. Then there is the fact that the timing can be broken by events on earth (http://en.wikipedia.org/wiki/McClintock_effect) rather than in the moon.
      It seems like women's body count 1-28 circadian cycles to form a pseudo-lunar cycle, rather than it being on an independent cycle.
    • More valuable research?
      I hope no scientists were harmed in these experiments.
      Was this from another of those fine 'scientific' journals?
      If you think it was, good luck with 6th grade.

    • There is only one type of person,that would consider this as news. A male scientist who's never lived with, dated nor talked to a girl, woman,or any other kind of entity of the female persuasion.
  • by Anonymous Coward

    Life on a submarine is an 18 hour day for months at a time. No sun, days, nights, weekends, not even the meals are in sync with the typical 12+6 work/sleep schedule. One cycle you wake up to dinner, the next time it's lunch, and then breakfast and so on. I don't know too many people that freaked out because of the strange schedule. Some faked or actually committed suicide but it was usually because of a wife/girlfriend.

  • ISTR that the period of the human body clock is not 24 hours, but 27.

    That is, if you remove the cues of time from someone, their natural sleep/wake cycle would rapidly approach 27 hours.

    Something about it being based on a relaxation oscillator which means the day/night rotation of the earth actually resets it constantly...

    • by jdbuz ( 962721 )
      Everyone's different. Some go longer some shorter. There's been a few deep studies on this but I think the most accessible description I've found is in the book Sync [amazon.com] by Steven Strogatz [wikipedia.org]
  • Different for me... (Score:5, Interesting)

    by fahrbot-bot ( 874524 ) on Friday September 27, 2013 @02:09AM (#44967909)

    My biological clock seems to run around a 26-30 hour cycle, which often makes it difficult for me to maintain "normal" work hours. Trying to go to sleep early is often fruitless so, eventually, I simply stay up all night and drag myself through the next day and then go to bed at an appropriate time to force reset my cycle. I've been this way for as long as I can remember - and I'm now 50. On the up side, I can (still) work productively for 36+ hours straight - I'm a senior mostly-Unix-ish system programmer/administrator btw.

    • by wonkey_monkey ( 2592601 ) on Friday September 27, 2013 @03:11AM (#44968115) Homepage

      and I'm now 50.

      On the plus side, that's only 43 in "you" years.

    • During a few weeks in my life when I had nothing going on, no job, no commitments, I just went to bed when I felt tired – or rather when I'd had enough of that particular day – with no regard for the clock.
      Over the space of a week, my living day had shifted by a full 12 hours. I found that quite amusing.

    • You've had this non-24 condition since birth? That's tough. I can't imagine having that problem as a kid while in school. Damn. It only started for me after a head injury, but now my normal cycle is also around 25-27 hours. It does make it extremely difficult to lead a normal life.

      I assume you've tried everything, but have you tried Dark Therapy? No artificial lighting after dark? It's kind of tough for me because it means I can't use a computer or read. I've sometimes listened to audio books though and a r

  • by stox ( 131684 ) on Friday September 27, 2013 @02:32AM (#44968005) Homepage

    The paycheck cycle.

  • I haven't worked in over two years so, when I don't have to be synced with other people, I go to sleep when I get tired and get up when I'm done sleeping. When I get going on an interesting project, I might chug away for 30+ hours straight then sleep for 10-12 hours. Or I'll get in a cycle where I'm down for 3-4, up for 10-12. When I'm just chugging along, I'm usually up for 18-20 hours and sleep for 8-9 hours and I chase that around the solar cycle. Being able to go for months without setting an alarm

  • From TFA:"Two papers published today present the first evidence for clocks independent of the circadian one:"

    Plenty of people have been doing non-circadian clock work for years; I briefly worked in such a lab that had been investigating food- and sex-based timing mechanisms, but the non-circadian clock idea is at least as old as the seventies.[1][2]

    [1] http://www.sciencemag.org/content/197/4301/398?ijkey=759219d8ce9c087620c8d8237098ff5956eeb489&keytype2=tf_ipsecsha [sciencemag.org]
    [2] http://jbr.sagepub.com/co [sagepub.com]
    • by osu-neko ( 2604 )
      Yeah unfortunately the summary is pretty bad (welcome to /.). It's obviously well known that there are non-circadian clocks in many plants and animals. When they say this is "first evidence for [the] clocks", they don't mean first evidence for their existence, but rather for a particular mechanism.

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