If you’re returning to work this week after spending New Year’s Eve in Hawaii, don’t expect much sympathy from your colleagues, or from me. However, some basic neurobiology can help you beat jet lag and ease yourself back into the land of the living.
The best way to re-jig your circadian clock is exposure to light. If humans are deprived of any natural or artificial light cycles - deep in a cave, or in a special lab - our natural sleep cycle is just over 24 hours. This extra half-hour or so means that our body clocks are all drifting westwards, so it’s more difficult to adapt from east to west than in the other direction.
A hormone called melatonin makes us feel sleepy, and like a vampire, it shrinks in the face of bright light. So after travelling west, take in sunlight and exercise as late in the day as possible. When you’re travelling east, the temptation to sleep late will be huge, but a brisk morning walk will help.
If you really are returning from Hawaii, try and go 14 hours west by having one very long day, as bringing your clock 10 hours eastwards will be even more painful than your colleagues’ jealous glares.
Dr Daniel Glaser is director of Science Gallery at King’s College London
