The studies I've read suggest, completely intuitively, that it's possible to establish a diurnal or nocturnal habit, but the people who do worst of all are those who have to adhere to a non-permanent shift system.
This makes sense to me, because I reckon my years as a junior doctor on-call completely fucked my body clock. Worst of all was probably the first year, when I live on-site and the boundaries between at-work and not-at-work were impossibly thin. I'd stay beyond my paid hours as a matter of course, would use days off to catch up on sleep and would regularly wake up not knowing if it was 7am or 7pm. Used to react to bleepy noises (supermarket checkout was a bugger) as if my pager had gone off. Worst point was when I fell asleep, standing up, on an escalator in a shopping centre. Slumped over the handrail and actually fell over when I got to the top - embarrassing.
Aaanyway, I think those years encouraged bad sleep hygiene habits, but also a degree of flexibility which has sometimes proved useful. I'm able, for example, to survive on 3, 4 hours' sleep per night for up to a week, so long as I catch up at the weekend. Problem is, I then can't sleep on Sunday night, so the cycle repeats itself. 'Course, I'm technically able to prescribe for myself, and keep meaning to go to the chemist and pick up a week's supply of Zolpidem or Zopiclone or summat, to try to reset my pattern. Must try to remember to give it a go. |