First sleep, second sleep.

I've written about this subject before. In 2006, I was amazed: "That's not insomnia, that's the natural sleep pattern breaking through!"

I'm fascinated by the idea of valuing this wakeful interlude by engaging in activities that, for one reason or another, are done especially well in an hour between two sleeps.

But here's a new article on the subject at BBC.com that a reader pointed out, and it made me want to revive the subject:

"For most of evolution we slept a certain way," says sleep psychologist Gregg Jacobs. "Waking up during the night is part of normal human physiology."

The idea that we must sleep in a consolidated block could be damaging, he says, if it makes people who wake up at night anxious, as this anxiety can itself prohibit sleeps and is likely to seep into waking life too.

Russell Foster, a professor of circadian [body clock] neuroscience at Oxford, shares this point of view.

"Many people wake up at night and panic," he says. "I tell them that what they are experiencing is a throwback to the bi-modal sleep pattern."

When I first heard about this back in 2006, I thought it might "change my way of living":

I have been thinking that it's just terrible to go to bed as early as 9 only to wake up and see that it's midnight. I've thought that it's important to stay up late enough that you won't just be taking what turns out to be merely a nap, a sleep snack that spoils my appetite for a full meal of sleep. Now, I'm going to think, it's time for first sleep. On waking at midnight, instead of thinking, oh, no, there's no way I can start the day this early if I can't get back to sleep. I'm going to think it's a valuable opportunity, use the time, and feel confident about the arrival of the wholly natural and not at all weird second sleep.

Ah! But I did not change my way of living. And just last night, I encountered and experienced as a problem the very thing I was going to reconceptualize as a valuable opportunity. How fortuitous to have this reminder today!