I travel internationally a lot, which means I deal with a lot of jet lag. This post is a quick summary of a system I’ve found helpful, based on this paper.
The basic principle: nudging your body’s minimum temperature¶
The basic idea is to shift your body’s internal clock by timing your exposure to light, exercise, and melatonin around your body’s daily minimum temperature (your lowest temperature in a 24-hour cycle, usually 2-3 hours before you wake up).
Light and exercise “push” your clock. If you get light or exercise before your minimum temperature time, you’ll push your clock later. If you do them after, you’ll push it earlier.
Melatonin “pulls” your clock earlier. If you take melatonin before your minimum temperature time, you’ll pull it earlier. If you take it after your minimum temperature time, you’ll pull it later.
Getting the timing wrong can accidentally push your clock in the opposite direction - this is especially true if you travel many timezones east. I try to keep my sunglasses on and stay indoors until after 1pm or so when I go to France!
Figure 1:A diagram explaining the basic principles of shifting your circadian rhythm.
Things to do while you’re sleeping¶
Buy melatonin before you go and keep it on your bedside table. The quality can vary, so it’s good to have a trusted source.
If you wake up in the middle of the night, take a small dose of melatonin immediately to help you get back to sleep.
Appendix: Schedules to follow¶
These are the schedules I refer to when I try to figure out “when my minium temperature is”. It’s an imprecise science and I just assume my time shifts by about 1.5 hours each night, if I have been taking all the right actions.
Click here to see the schedule for traveling east.
Figure 2:When you travel east, you need to advance your clock (shift it earlier).
Click here to see the schedule for traveling west.
Figure 3:When you travel west, you need to delay your clock (shift it later).
How to read the schedules¶
Gray boxes: Sleep
White boxes: Wake
Yellow boxes: Get light exposure
Black boxes: Avoid light
Red circles (M): Take melatonin (3.0 mg dose)
For a deeper dive, check out the original paper.
- Roach, G. D., & Sargent, C. (2019). Interventions to Minimize Jet Lag After Westward and Eastward Flight. Frontiers in Physiology, 10. 10.3389/fphys.2019.00927