Photoperiods and sleep

I was poking around PubMed today, doing research on melatonin and its effects on sleep, and came across this abstract. It says that humans will naturally adapt to a biphasic sleeping cycle if the photoperiod (read, daylight time) is decreased to 10 hours (as opposed to 16).

The sleep periods are broken into evenly spaced segments, spaced apart by a few hours.

It made me think that maybe, with manipulation of lighting and light spacing, one could induce a more-segmented polyphasic sleep schedule. Though, I doubt one would be able to induce Uberman sleep from light cues. According to Wikipedia (under Circadian Rhythm), the suprachiasmatic nucleus (SCN), which regulates the circadian cycle in humans, doesn’t react quickly to light changes, so it would probably be difficult to induce 20 minute bursts of sleeping.

It’s a thought, though… (I'm slipping into speculation mode, now) for those that are having trouble initially during those nighttime naps, it could be because the SCN is targeting your body for sleep. Using bright lights (say, a few thousand lux) constantly during this period could convince the SCN that it’s not night time. This might make those naps a little easier to wake up from, since your body would not be preparing for normal sleep.

Of course, generating that amount of lux might be a bit tricky… perhaps just normal lighting shone close on one’s body (like a desk lamp pointed at one’s face) would work. I’ll have to check the math to see what would be needed.

-sean