---
title: "Jet lag"
license: CC-BY-SA-4.0
license_url: https://creativecommons.org/licenses/by-sa/4.0/
source: https://en.wikipedia.org/wiki/Jet_lag
source_license: "CC BY-SA 4.0 (Wikipedia)"
attribution: "Summary by iinventedlight (AI-assisted). Source: Wikipedia, \"Jet lag\" (CC BY-SA 4.0 (Wikipedia))."
condensed_by: "iinventedlight (Grok Bot, AI-assisted)"
fact_checked: 2026-10-14
date: 2026-10-14
status: reviewed
reviewed_on: 2026-10-14
category: travel
checked_on: 2026-10-14
sources:
  - id: S1
    title: "Jet lag"
    publisher: Wikipedia
    url: https://en.wikipedia.org/wiki/Jet_lag
    accessed: 2026-10-14
    license: "CC BY-SA 4.0 (Wikipedia)"
---
# Jet lag

## Summary
Jet lag is a temporary mismatch between your body clock and the local time zone after fast travel across several time zones; most people find eastward travel harder.

> **General information. Entry rules change; confirm with travel.state.gov and official EU sites before you travel.**

> **General information, not medical advice. See a clinician about your own situation; in an emergency call 911 (US).**

## Facts
- id: F1
  claim: Jet lag is a temporary condition where the circadian rhythm is out of sync with the local time zone after rapid travel across multiple zones.
  confidence: medium
  date: 2026-10-14
  sources: [S1]
  license: CC BY-SA 4.0
  checked_on: 2026-10-14
- id: F2
  claim: Flying east advances the body clock (phase advance); flying west delays it (phase delay).
  confidence: medium
  date: 2026-10-14
  sources: [S1]
  license: CC BY-SA 4.0
  checked_on: 2026-10-14
- id: F3
  claim: Most travelers find adjusting harder after eastward travel.
  confidence: medium
  date: 2026-10-14
  sources: [S1]
  license: CC BY-SA 4.0
  checked_on: 2026-10-14
- id: F4
  claim: It is classed as a circadian rhythm sleep disorder rather than ordinary travel fatigue.
  confidence: medium
  date: 2026-10-14
  sources: [S1]
  license: CC BY-SA 4.0
  checked_on: 2026-10-14

## Pointers
- answers: Prevention and treatment tips (light exposure, melatonin, timing)
  where: CDC Yellow Book, Jet Lag chapter (cdc.gov/yellow-book)
  access: open; URL moved, fetch returned 404—find current URL