I had a Psychology teacher back at New College (who's now apparently an expert in the Klingon language), who used to talk about how the human body had these ±90-minute cycles. And that if you could become aware of yours, you could do Great Things -- particularly because you could learn the optimal time to snag a nap versus, say, try to cure small-cell carcinoma.

Not sure if this is exactly what he was talking about, but I am certainly fascinated by the idea of ultradian rhythms:

Ultradians are the regular recurrence in cycles of less than 24 hours from one stated point to another, as certain biologic activities which occur at such intervals, regardless of conditions of illumination.

Commonly used in sleep research to describe individual stages of sleep that occur within intervals of an organism's circadian rhythm, and especially to refer to the 4-hour ultradian cycle.

A guy named Rossi appears to be the mainstream gorilla in this field, especially as it pertains to "healing" (or, to put it less fancily, rest and renewal). He wrote a book called The 20 Minute Break and has a site where I found this overview/interview:

The basic idea is that every hour and a half or so you need to take a rest break - if you don't you may be well on your way to the Ultradian Stress Syndrome: you get tired and lose your mental focus, you tend to make mistakes, get irritable and have accidents - If you continue to ignore your need to take a break you can experience more and more stress until you actually get sick.

When you learn how to recognize your need to take a 20 minute break you can convert your stress into what I call The Ultradian Healing Response - Its that wonderful feeling of comfort and well being that you naturally have when you are tired but let yourself have the freedom to take well deserved rest.

Just learned about this stuff last night, so, no, I haven't read much more than what I'm posting here yet. Thing is, I recently started taking 20-minute naps every day (with the assistance of the most excellent Pzizz), and the effects so far have been profound. So I'm especially interested in whether there's a connection here. What do you guys say?

What's the deal with ultradians? Is there anything to this? Does this jibe with your experience? Prof. Schoen, are you out there?