Jet lag is a temporary mismatch between your body clock and local time after crossing time zones quickly. These four guides cover what it is, why it happens, its symptoms, and how long it lasts — in plain English, with links to the calculators when you want a plan for your own trip.
Start with the basics
- What is jet lag? — the plain-language overview.
- Why does jet lag happen? — the body-clock mechanism, step by step.
- Jet lag symptoms — what to expect, and for how long.
- How long does jet lag last? — the “one day per time zone” rule and its limits.
Ready for a plan? Put your route into the jet lag calculator, or read the deeper science of jet lag.