Jet Lag vs Travel Fatigue: What's the Difference?

Jet lag is a circadian-rhythm problem caused by crossing time zones. Travel fatigue is a physical-stress problem caused by long sitting, dehydration, and the cognitive load of travel itself.

How to tell which one you have

Crossed three or more time zones and feel wide awake at the wrong hour for several days? That is jet lag. Stayed within one or two time zones but feel wiped out? That is travel fatigue, and it clears with one or two normal nights of sleep.

Why the difference matters

Travel fatigue resolves on its own with rest, water, and movement. Jet lag does not — it requires actively pushing your circadian rhythm in the right direction with timed light, sleep, and meals.

When they stack

On long-haul flights you usually have both. Handle the fatigue first (hydrate, walk, eat a normal local meal, sleep at a reasonable local time), then run a circadian plan over the next several days for the jet lag.