Dear
George,
Lately
I’ve been sleeping sort of fitfully.
I usually fall asleep fairly quickly, but then I wake up around 3
a.m. I can’t believe how wide
awake I am; I can lay there for an hour or more before I start feeling drowsy
again. I was going to ask
the doctor if I’m suffering from a sleep disorder. However, then I ran across some sleep research by a
psychiatrist named Thomas Wehr. In
a month-long experiment Wehr kept individuals in a completely dark room for 14
hours a day (the length of a midwinter night in the Great White North). Instead of sleeping for the
8-hour stretch that we’re accustomed to thinking of as normal, individuals’
sleep patterns changed dramatically by the end of the month. Typically they lay quietly in bed for
an hour or two. Then they fell
asleep for a three to five hour period.
They then woke up for an hour or two. And finally they went back to
sleep for another three to five-hour segment. Thus, their sleep pattern was bimodal. Instead of a single uninterrupted stretch,
individuals typically had a "first sleep", followed by a fairly
lengthy wakened state, and then a "second sleep". Interestingly, this sort of bimodal
sleep is the pattern normally shown by a wide range of other mammals, as well
as birds and reptiles. (I’m
not really positive if aardvarks sleep this way, but I imagine they do.)
A
historian named Roger Ekirch concluded that the belief that a continuous
eight-hour stretch of sleep is normal is a peculiarly modern phenomena, an
apparent product of the industrial age.
Using diaries, medical books, religious papers, etc., Ekirch established
that before the nineteenth century people in Western Europe regarded waking in
the middle of the night as commonplace and to be expected. People normally got
up at this time, read a book, wrote in their diaries, interpreted their dreams,
did chores, smoked, prayed, visited neighbors, even engaged in petty crime. He
suggests that the invention of electric lighting made late night hours much
more feasible and helps explain the waning of bimodal sleep in modern times. Anthropologists have further documented
interrupted sleep patterns in a variety of non-Western populations, e.g.,
hunter-gatherers in Africa, herding tribes in Pakistan. Scientists speculate that there may be
an evolutionary advantage to interrupted sleep since it leave people and
animals less vulnerable to predators.
Age
has been connected to bimodal sleep too.
Sleep researchers find that deep sleep is much less common in people in
their seventies and beyond, and bimodal sleep tends to become increasingly
frequent. Ever since I found that
out, I’ve been working on embracing bimodal sleep. Now that I’m retired and don’t have to worry about a work
schedule, I look forward to being up and around for in the early morning
hours. I go to the computer, check
my e-mail, play a couple of games of computer solitaire, maybe work on a draft
for my blog. By 4:30 or so my eyes
start drooping again and it’s back to bed. The sheepdogs wake me promptly at 9, and it’s time to start
the new day. This seems like a
pretty good use of time. There’s a
lot we can learn from the aardvarks.
Love,
Dave
SOURCES:
www.nytimes.com, "Awakening to
Sleep" (V. Klinkenborg, 1997); www.nytimes.com, "Sleep Disorder? Wake Up and Smell the Savanna" (R.
Friedman, 2006); www.utne.com, "The No Wake Zone: Can't sleep through the
night? You're not supposed
to." (M. Wylie, Psychotherapy
Networker, 2009); www.wikipedia.org, "Segmented sleep"
G-mail Comments
-Phyllis S-S
(10-11): Dave, Interesting: Matt
is more like you but I sleep soundly for 9 hours; I do not even hear
terrible thunder storms; We are in a cute village in Provence… Best Phyllis
OK I give up. How did you acquire or arrange that picture?
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