Sleeping when the world is awake

Sleep is where shift work collects its debts. You cannot argue with your body clock, but you can steer it, and the difference between a steered clock and an ignored one is roughly the difference between tired and unwell. These are the mechanics.

The one non-negotiable block

Whatever your shift, defend one core sleep block of at least 6 hours in every 24. After a night shift, that means going down soon after arriving home, before the daylight and the household fully wake you. A short evening nap before the next night shift tops you up; it does not replace the core block.

Light is the steering wheel

Bright light tells your clock it is daytime. So: bright light at the start of a night shift, sunglasses on the commute home, blackout in the bedroom. In the other direction, if you are switching back to days, get outside in the morning light and the clock follows within a couple of days.

Caffeine, food, screens

• Caffeine has a half-life of about 5 hours: last coffee no later than the middle of a night shift.
• Eat your main meal before the shift; keep the middle-of-the-night food light.
• Screens in bed do to your clock what coffee does; the bedroom works best as a dark, cool, boring place.
• Alcohol brings sleep faster and wrecks its second half; after nights it is a bad trade.

When it is more than tiredness

If you regularly cannot sleep during your protected block, doze off at the wheel, or feel low for weeks, that is shift work sleep disorder territory and worth a doctor's visit; it is common, recognised and treatable. And fix the schedule side too: irregular, short-notice rotas hurt more than any fixed pattern. Knowing exactly when you work weeks ahead, with alarms that match, removes a whole layer of stress; that part ShiftAl can do for you today.