Jet Lag & Circadian Shift Planner
Calculate the fastest biological path across time zones with targeted morning or evening light timing.
Why does timed sunlight help reset jet lag?
Bright light is the main cue that shifts your internal circadian clock. Flying East requires advancing your schedule earlier, while flying West delays it later—seeking or avoiding light in the listed windows speeds up adaptation.
| Day | Target Bed | Target Wake | Seek Bright Light | Minimize Light / Sunglasses |
|---|---|---|---|---|
| #1 | 6:00 PM | 2:00 AM | 2:30 AM – 4:00 AM | 11:00 PM – 1:00 AM |
| #2 | 7:00 PM | 3:00 AM | 3:30 AM – 5:00 AM | 12:00 AM – 2:00 AM |
| #3 | 8:00 PM | 4:00 AM | 4:30 AM – 6:00 AM | 1:00 AM – 3:00 AM |
| #4 | 9:00 PM | 5:00 AM | 5:30 AM – 7:00 AM | 2:00 AM – 4:00 AM |
| #5 | 10:00 PM | 6:00 AM | 6:30 AM – 8:00 AM | 3:00 AM – 5:00 AM |
| #6 | 11:00 PM | 7:00 AM | 7:30 AM – 9:00 AM | 4:00 AM – 6:00 AM |
10,000-Lux Light Boxes & Blackout Masks
Anchor morning phase shifts during cloudy travel days or block cabin light during westward flights.
Review Travel Sleep KitFrequently Asked Questions
Why is traveling East harder than flying West for jet lag?
Human endogenous circadian rhythms average slightly over 24 hours (~24.2h), making it naturally easier to delay bedtime flying West (~1.5h/day) than to advance sleep earlier flying East (~1h/day).
How should I time bright morning sunlight after crossing time zones?
Seek bright outdoor light after your body-clock temperature minimum when flying East to pull your rhythm earlier, and seek late-afternoon/evening light when flying West to delay sleep.
Should I adjust my sleep schedule before departure?
Starting 3 days prior by shifting bedtime, meals, and light exposure 45 to 60 minutes per day toward the destination clock significantly cuts arrival fatigue.
Optimize the rest of your 24-hour sleep routine
Pair your cycle window with caffeine timing, power naps, or weekly sleep debt tracking.