Counting Sheep

A few months ago, I started to wonder about the mystery of my sleep patterns. Some weeks, I would get by with five hours each night, and get lots of work done. Other weeks, I would sleep eight hours a night, and still be exhausted during the day. I had the idea that perhaps by collecting data on my sleep patterns and how awake I felt, I could figure out a mathematical model that would be able to correctly predict how tired I would feel each day. I reasoned that if I had such a model, I could use it to figure out how much sleep I needed to get in order to get things done, because I find it very frustrating to plan a late night of work, only to find myself too tired to do anything.

So, I collected data on myself for several weeks, and played around with some simple models, and sadly, none of them seemed to match the data at all. I was complaining about it to Drew Davidson, and he suggested I read Counting Sheep by Paul Martin. He wasn't sure it would help, but he said it was interesting anyway.

And he was right! It was interesting. It is basically a guided tour of the science of sleep, trying to touch every aspect. It doesn't get very deep, but it gives a little bit of info about everything. It's also full of interesting quotes and examples from history, literature and mythology, which keeps it from being a dry read.

Some of the fun facts I learned in Counting Sheep:

• People who are early risers tend to have more stress chemicals in their blood (that explains why you early people act like that!)
• People who have frequent nightmares are easier to hypnotize. I will be thinking about that for a long time.
  
• We don't just dream during REM sleep -- there are also dreams during NREM sleep, but they are a bit different.
  
• I knew when you were falling asleep, it is called the "hypnogogic state", but know I know that waking up is the "hypnopompic state."
  
• I learned the horror of Ondine's Curse.
  
• If your eyes don't keep moving, oxygen doesn't get to the iris. This may be part of the reason for REM sleep.
  
• There are two kinds of sleep apnea: "obstructive" (the normal kind, where your throat collapses while you sleep), and "central", where some kind of brain damage makes you stop breathing in your sleep.
  

I found this book a nice complement to Stanley Coren's Sleep Thieves, which has a different set of facts, more oriented towards why sleep is important. Counting Sheep is more of a general overview of the history and science of sleep. And though it was fun, I still don't have a mathematical model that can predict when I'm too tired to work. If you have one, please let me know!