Jet lag — 0 seconds

Follow a representative body-clock shift over the week after an eastward flight across six time zones.

Representative model

Loading interactive anatomy

Arrival · 00:00:00
First local night · 12:00:00
First full local day · 24:00:00
Shift underway · 48:00:00
Sleep begins to settle · 72:00:00
Most of the shift completed · 120:00:00
End of the teaching window · 168:00:00

Happening now

Local clocks have moved six hours ahead; the internal schedule is still close to the departure zone, so the displayed offset is at its widest.

Explore the mechanism Local time jumps; the body clock does not

A flight moves local clock time by hours. The internal circadian schedule that times sleep, alertness, hormone release and digestion stays close to the timing of the departure zone.

Evidence for this step

Crossing several time zones faster than the circadian system can follow typically leaves internal body timing out of step with local clock time, and that misalignment is what generates jet-lag symptoms. moderate · View sources

Recommended support

Read the ranges as a teaching modelThe sequence explains coordinated timing physiology for one modelled trip. It is not a target, a measurement or a forecast for an individual traveller, and the displayed range widens over the week because adaptation rates differ.
Direction of travel changes the pictureThese curves follow an eastward crossing, where the internal clock has to move earlier. A westward trip asks the clock to move later, which the circadian system generally does more readily, so a westward event would need its own reviewed curves rather than a mirror image of these.

Model status

Representative modelEducational only

Educational physiology only; not medical advice, diagnosis or treatment guidance.

This event shows a representative pattern for a modelled trip, not a personal prediction.
Only an eastward crossing of six time zones is modelled; westward travel and other zone counts behave differently and are not shown.
Individual adaptation varies widely: field measurements have found some travellers shifting close to an hour a day while others shifted far more slowly or not in the expected direction at all.
Displayed ranges are conservative teaching ranges and have not yet received the domain review this medium-risk event requires before publication.

Jet lag — 0 seconds

Body-clock offset behind local time

Daytime sleepiness

Night sleep continuity, compared with usual nights

Alignment with local time