Long-haul circadian disruption, jet lag, and regulatory rest windows — optimized with chronobiology.
Crossing 3+ timezones forces a re-sync of your circadian clock at ~1 hour per day in either direction.
Hotel rooms, noise, light leakage, and unfamiliar beds all compound circadian disruption on layovers.
Bunks, cabin noise, pressurization, and vibration reduce sleep depth even during protected rest periods.
A single disrupted night isn\u2019t the problem — it\u2019s four or five in a row that produces measurable performance deficits.
In the 48 hours before a long-haul, start shifting your sleep window toward the destination timezone by 30–60 min per night.
Use bright light in the "new" morning (local morning) for 30 min to accelerate re-sync. Avoid bright light in the new evening.
If you have 4+ hours between flights, a full 90-minute cycle nap recovers more than two 20-min naps spread across the same window.
Low-dose melatonin (0.3–0.5 mg) taken at the *target* bedtime in the new timezone accelerates adaptation. Higher doses are counterproductive.
Pre-flight west-to-east (e.g. NYC → London): • 2 days before: shift bedtime 1 hr earlier • 1 day before: shift bedtime 2 hr earlier • Flight day: light exposure at new-destination dawn • First London night: 0.3 mg melatonin 3 hrs before local bedtime In-flight rest: • Aim for 90-min blocks (one full cycle) • Eye mask, earplugs, compression — non-negotiable • Avoid caffeine in the last 2 hours before protected rest
Every number on this page assumes you\u2019re an average sleeper. You probably aren\u2019t. Our 2-minute calculator gives you the exact bedtime that matches your cycle length — not the generic 90-minute assumption.
Start the calibration→Pre-shift the circadian clock before departure (1 hr/day in the direction of travel), use bright light at the destination "morning", and use low-dose melatonin (0.3 mg) timed to target bedtime.
Treat the layover like you\u2019re in the new timezone immediately. Bright light in local morning, blackout in local evening, and sleep in 90-min or 180-min cycle-aligned blocks.
Yes, at low doses (0.3–0.5 mg) and correct timing (3 hours before target bedtime in new timezone). High-dose "sleep-aid" melatonin is less effective and can cause grogginess.
Eye mask, earplugs, compression socks, a light meal 2+ hours before rest, no caffeine 4+ hours before, and target 90-min cycle blocks.
Pre-shift bedtime earlier for 48 hours, hydrate aggressively, take a 90-min nap before boarding if possible, and avoid alcohol in-flight — it suppresses REM and worsens next-day function.