I’ve spent the last hour reading SuperMemo’s fascinating article on sleep. I can’t vouch for the quality of the scientific references, but the information certainly seemed self-consistent and reasonable. In it the author identifies two factors which cause sleepiness:
- circadian component – sleepiness comes back to us in cycles which are usually about one day long
- homeostatic component – sleepiness increases with the length of time we stay awake
and claims that sleep is possible only when the ‘peaks’ of each rhythm coincide. High homeostatic / low circadian tiredness results in tossing and turning, with a high body temperature and your thoughts racing. The opposite is evidenced by a total lack of energy and willpower, with sleep not helping even if manageable.
The article states as fact that the function of sleep is for processing of information without external stimuli, rather than rest. Indeed, it claims that the physical energy gained by sleeping is comparable to that gained by eating an apple. Studies have apparently shown conclusively that sleep deprivation has been causally linked with memory retention.
Ok, so far, so obvious. What’s most interesting are the inherent problems with the sleep patterns of the majority of people. Key to this is that the circadian rhythm has been shown, in the majority of cases, to be 24.5 – 25.5 hours long. The reason for this isn’t obvious, but is likely to be the evolutionary result of millions of years of seasonal daylight variations. Whatever the cause, it’s been demonstrated to be the case. The advent of artificial light and the move to strict 24-hour days throws this system out of whack. Hence 50% of adults have trouble sleeping and getting up on time.
The article readily admits there’s no easy solution to this problem. There is a way to fix sleep patterns, but fitting it in with real-world interactions isn’t easy for the majority of people. The recommendation is, quite simply: go to bed when you feel you’ll fall asleep within 20mins, and wake naturally. This is called ‘free-running sleep’. Clearly, this will cause your waking hours to wander. The author debunks various myths that counter this idea: it’s entirely possible to sleep when the sun is up, if the body is actually tired; the body will not ‘ask for’ more sleep than necessary (as it will with food) if it gets the chance, although this may happen in the initial stages of adjustment; it’s not healthy to have a regular rhythm if you’re fighting the inherent rhythms of the body1.
The article arouses suspicions on occasion, quoting the ‘half-life of caffeine’ for example, and I’d like to read more on the subject, but it’s a fascinating idea. I highly recommend reading the entire thing – if you do, please let me know what you think.
It would be terribly difficult to adapt such a system – I’m not sure how I’d cancel a lunch date upon realising I’ll be asleep – but it’s very tempting to try out. Maybe I could give it a go during November while I’m writing my novel.
- ugh, this sounds hokey, doesn’t it [↩]