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(meteorobs) On sleep, observing and circadian rhythms
Michael writes:
>I continue to read about how many of you observe all night for a few nights
>then go back to a "normal" sleep-wake schedule then stay up all night
>again. I always have found that when you sleep is determined by habit. For
>example: If for about a week or more you go to bed at 9:00pm then the
>following week you will naturally be tired at 9:00pm. Many people who work
>night shifts are naturally awake all night and are use to sleeping in the
>day. But for a meteor observer who has school or work during the day; how
>do you constantly change the sleep-wake schedule on your body and on some
>nights, when you don't observe, sleep. And stay awake on other nights to
>observe for seemingly long hours?
>Michael
Michael and others,
To say sleep is DETERMINED by habit does not really get to the crux of
the issue. You will only be tired at 9pm for a few days until the body
physiology adapts to the new schedule. Good suggestion by Kevin to
start the 'phase'-shifting a few days prior to meteorobs using a nap
stratagy. Careful WHEN you nap, though. Naps during ciracdian peak
appear to be less 'restorative' than naps during circadian nadir. Some
carefully administreed bright light may help (more on that later..)
Sleep is the result of a multitude of internal factors (body temp,
melatonin and various other 'sleep' hormones) and external factors (called
Zietgebers, light being the most importanmt). Theoretically, some say sleep
is result of two-step processe: Circadian Rhythms and Sleep
Propensity (or 'sleep debt'). This 2-process model has, by and large, been
empircally validated. The short end of it.... WHEN one sleeps is largely
determine by circadian phase and prior wakefulness. Irregular sleep
schedules and sleep deprivation perturb the whole system. And, from
experience, it sure does seem that irregular sleep/wake schedules are the
rule and not exception among meteor observers. People are different, to be
sure, and different idiosyncratic stratagies and counter-measures are taken
to deal with this irregularity. Some work. Most don't. That's why we do
sleep research.
The circadian variation in numerous cognitive and psychomotor
performance measures has been well documented and, with few exceptions, the
variation in alertness and cognitive psychomotor performance across the
24-hr day parallels the circadian course of body core temperature, with a
performance nadir (low) around the temperature minimum (~3-6am). When is
the best time to collect visual meteor data?? Thus, until proper
adaptation/phase-shifting occurs, people working night shift (AND visual
meteor observers!) will continue to work (AND collect data) during their
performance/alertness low, while sleep deprived. Not a very desirable
state of affairs.
Currently, we have several ongoing research projects at The Human
Circadian Pacemaker and Sleep Research Lab, Univ of Calif School of
Medicine, San Diego, CA. Primarily, we assess sleep (using EEG) and
circadian rhythms (using core body temp and endogeneous melatonin rhythm as
phase markers) and then administer carefully measured and precisely
timed BRIGHT LIGHT exposure in an effort to phase-shift ciracadian rhythms.
We than assess perfromance with a variety of computer based
cognitive and behavioral tests.
Now, during our recent GEMINID campaign, I saw Bob stuggling to stay
awake and alert. My first night, I knew if I attempted to stay up all
night, early morning data would be less than reliable. And since it was
so active early i the evening, I decided that collecting data from 7pm to
midnite would yield the most dependable results. I then took a 3 hr nap and
awoke at 245am to do a 1hour session from 3-4am. Im sure that had I stayed
up all night, my 3-4am data would be far less reliable. In that hour (Dec
12/13 1100-1200 UT) I saw 50 GEM, 1 XOR and 8 SPO.
F Y I ... The Harvard Circadian Research Lab (under Dr Charles Czeisler)
has put out 3 seminal articles in the area of sleep, circadian rhythms are
phase-shifting using bright light. All published in the journal SCIENCE.
1. Czeisler CA et al. Human Sleep: its duration and organization depend on
its circadian phase. SCIENCE 1980;210(4475):1264-7.
2. Czeisler CA et al. Bright light resets the human circadian pacemaker
independent of the timing of the sleep/wake cycle. SCIENCE
1986;233(4764):667-71.
3. Czeisler CA et al. Bright light induction of strong (type 0) resetting
of the human circadian pacemaker. SCIENCE 1989;244(4910):1328-33.
In conclusion, to answer Michaels query on what to do. In order to stay
up all night and sleep in the day requires a circadian phase-delay. Delay
sleep onset and delay/shift body temp nadir. Suggestion: A single
4-hr exposure of bright light (6000 Lux) between 0000 and 0400 the nite
before meteorobs. Then day sleep in DARK ROOM for however long you can
(6-8 hrs), then awaken to go out and do meteorobs. this has been shown to be
an effective stratagy for shiftworkers, however, for observers (myself
included), I can not afford to stay up the night BEFORE meteorobs (for
light treatment) due to the need to work in the daytime prior to meteorobs.
This is probably the case for most of us. So either daytime job performance
suffers or meteorobs performance suffers. What do I choose. Well... Meteor
observing doesnt pay my bills.
Hopefully, some of you found this (somwhat) interesting.
With regards and good sleep & clear skies to all,
Joseph D. Assmus
Sleep and Circadian Studies, UCSD
San Diego, CA