ems@Apple.COM (Mike Smith) (02/07/89)
In article <Added.4XlHiiy00Ui38HQE8q@andrew.cmu.edu> GILL@QUCDNAST.BITNET writes > > A few weeks ago, there was a report on the boob-tube about a lady >in France who had spent about 60 days inside a cave (mineshaft?), >completely isolated with no timepieces. She was startled when they >brought her out and said her time was up, as it seemed that she had >often spent 40 - 60 hours awake at a stretch without noticing. > This is likely to be due to her own quirky construction. I find this claim (40-60 hour days) a bit hard to swallow. Are you sure it is correctly quoted? > The question then becomes, how ingrained are our sleep patterns to >our environment? How does this effect manifest itself in long-term >orbits (like in Mir)? Does the proximity of timepieces and the day-cycle >of the earthbound communications force the astronauts to keep the >`normal' day cycle? What is the effect of having two or more people >setting up their own `day' cycles? Our sleep patterns are pretty strongly engrained. There have been several other studies that have resulted in the conclusion that most folks have a 'natural day' of about 22-27 hours. More people tend to be a bit on the long side than on the short, but some are in each camp. Changes of a few hours are OK, but much beyond that is chaotic. I would surmise that since most folks will be close to a 24 hour day anyway, it would be simplest to just keep them in sync at 24. When 2 or more folks are allowed to 'free run' and set up their own days, one of them becomes the biological leader and the others drift into sync with them. This person may not be the social leader. [Mars speculation deleted ...] > If nothing else, more experiments could be done on isolation >experiments similar to the French one (i.e. no contact, no *clocks*), >especially the effect of having two people involved (against setting up >your own rhythms). Just a thought - go to it, thought-busters! It has already been done. I know from first hand experience. I was one of the subjects in a study of social isolation and circadian rythyms done at UCDavis in about 1972. When SkyLab was going for 85 days in space, we were going for 105 days on the ground. They played all kinds of games with our timing (including several weeks at a time of 'free running') and switching 'noon' to happen at our biological 'midnight'; talk about jet lag! We had no idea what day, date, or time is was. Several interesting conclusions were derived. (I'll be brief and only list a couple...). One was that the social leader did not corelate with the biological leader (positive or negative corelation). Another was that the scale of 'augementer/reducer' did corelate. (This means, to grossely simplify, that night people like to be left alone in the dark while morning people like stimulation and crowds and bright lights...) One guy in our group had a natural day of about 23 hours. Mine was about 25.5 hours. We 'settled' on 25 hours (i.e. I was the biologic leader and moved his pattern more than he moved mine.) The third guy was a 24is hour type and didn't have much influence on the drift rate. No group had anyone much beyond a 26 hour day during 'free run' intervals. My experience would lead me to suspect anyone who claimed that a 40-60 hour day was not noticed by the participant(s). I would look closely at the issue of 'naps', also. If anyone wants me to add more on this, let me know; otherwise I'll assume that this posting was already too long!
ems@Apple.COM (Mike Smith) (02/07/89)
In article <10365@well.UUCP> tneff@well.UUCP (Tom Neff) writes: >I strongly urge all you cave dwellers out there to factor in the >resource cost, not just of spending X months *at equilibrium* at some >artificial day length, but of sustaining two or three *transitions* >between day lengths, all the while trying to run a Mars mission at its >most critical moments. This pre-supposes that there IS a resource cost in making a transition or that there is a resource savings at some schedule. I would make the (bald faced, poorly supported) assertion that this is not true. I underwent many transistions (during a study described in a prior posting) and spent weeks at a time on free run, then shifted to another schedule and free run. My resource consumption profile? Consistently downward over time, leveling out at about a starvation level of calories. (1100-1200/day). The dominant factor BY FAR was that there wasn't much to do in a room 11x17 with two other guys, bunk beds, chairs, and a TV, other than be a couch potatoe. Since most of my time was spent laying down or sitting, I didn't consume much. Period. Free run day or day-night schedule. The cost of a transisition is NOT resources, but rather PERFORMANCE. We were awakened at the bottom of our {heart rate, temperature, etc} curves and put on a flight simulator. Being at a bottom (or going through a desyncronization) resulted in SIGNIFICANT drops of performance. The conclusion? Keep folks syncronized, but out of phase. (i.e. have one person who is awake and near a body temperature high point on each shift so that they will perform well in an emergency.) The exact interval for syncronization doesn't matter much, but time in the range of 22-28 hours are easiest for most folks to accept (given our sample of 9 people in a 3 1/2 month study). Unless there is an overwhelming need for something other than 24, it wouldn't be worth the confusion of using a non-standard day, IMHO.
Dale.Amon@H.GP.CS.CMU.EDU (02/13/89)
For people interested in doing some background reading on the subject of this thread, I suggest the Scientific American book, "Wide Awake at 3AM, By Choice or By Chance?" There is a bit of meat to the freerunning clock argument.