Cory Doctorow linked today to a fascinating explanation of sleep, entitled “Everything You Always Wanted To Know About Sleep (But Were Too Afraid To Ask)“. Here’s a snippet:

Melatonin is secreted only at night (circadian clock time) and is not dependent on sleep. However, bright light tends to reduce melatonin levels. In summer, nights are short, thus the duration of the melatonin “signal” is short. In winter, nights are long, thus the duration of the melatonin “signal” is long. The duration of the melatonin signal is the cue that the circadian clock (this is in mammals only) uses to detect season, i.e., the changes in photoperiod (daylength) – information important for timing of seasonal events, e.g., molting, migration, hibernation, reproduction. Humans are only mildly seasonal – our ancestors about 70 million years ago were living in little holes in the ground, were tiny, were nocturnal, were seasonal breeders, and were hibernators. Some traces of our ability to measure photoperiod are retained in “winter blues”, or Seasonal Affective Disorder (SAD). It is almost a form of hibernation.

Back when I was taking kung fu lessons, I was very interested in the body’s natural abilities, including the “internal body clock”. (I even wrote a Mary Sue in which I had mastered it. I also passed myself off as a man named Julien in the story…but I digress.)

I never actually discovered anything about the body clock, but this article reminds me how interesting our bodies’ natural systems are. I’d like to figure out the healthiest routine for myself, the one that would bring forth natural productivity. Analyzing sleep patterns will presumably help, as will sticking to a healthy diet. I suppose what I need to do is start compiling all the information I find on the subject.

One other part that struck me:

If you are asleep, this means you need it. If you are rested enough you cannot physically remain asleep or go back to sleep again. You are wide awake. Thus, when you see someone asleep, it is because that person needs sleep right there and then. Sleep is not laziness.

And here’s something scary.

The problem with jet-lag and shift-lag is dissociation of rhythms between cells in different tissues, i.e., your brain clock may resynchornize to the new time-zone/schedule in a couple of days, the clocks in your heart and lungs in a week, and in your stomach and liver in a month. In the meantime, everything in your body is desynchronized and you feel really bad. If you keep changing your work shift over and over again, you never get to achieve complete synchronization, leading to long-term effects on health, including significant rise in heart attacks, stomach ulcers, and breast cancer.

I now would very much like for Sean to stop working rotating shifts.

There’s far more information than just the above to be found in the piece. For example, the section “Treating Extreme Larks and Owls” is intriguing (and funny). I recommend everyone check it out.