Jet Lag Calculator
Time Zones Crossed
Direction
Jet lag is a temporary circadian rhythm disruption from rapid travel across time zones. The internal clock — regulated by light — takes time to sync with the new local time.
- 1Typical recovery: ~1 day per time zone crossed
- 2Eastward travel (phase advance) is harder than westward
- 3Melatonin at local bedtime helps reset the clock
- 4Morning light exposure at destination speeds adaptation
London → Tokyo (9 time zones east)=Recovery ≈ 9–12 days; take 0.5–5mg melatonin at local bedtime for 5 nights
| Strategy | Evidence |
|---|---|
| Melatonin at local bedtime | Strong |
| Morning bright light at destination | Strong |
| Avoid alcohol/caffeine in-flight | Moderate |
| Pre-trip sleep schedule shift | Moderate |
| Stay well hydrated | Mild |
References
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