Guide · 10 min read
How to Beat Jet Lag
Jet lag is not "feeling tired after a flight." It's your body running on the wrong clock. The fix is to shift the clock — deliberately, in the right direction, using the right levers.
What jet lag actually is
Every cell in your body runs on a 24-hour rhythm coordinated by a master clock in the brain (the suprachiasmatic nucleus). When you fly across timezones, that master clock stays anchored to your home time while the world around you switches. The symptoms — insomnia, daytime fatigue, GI issues, brain fog — are the gap between your internal time and external time.
Eastward vs. westward (and why east is harder)
Your internal day naturally runs slightly longer than 24 hours. That means delaying your clock (flying west) is easier than advancing it (flying east). Rule of thumb:
- East: ~1 day of recovery per timezone crossed.
- West: ~1 day per 1.5 timezones crossed.
- >12 hours: shift in the easier direction (treat NYC→Sydney as westward).
The 3 levers, in order of impact
- Light timing is the strongest signal — by an order of magnitude. Bright morning light advances your clock; bright evening light delays it. Get it wrong and you can deepen jet lag, not fix it.
- Sleep timing matters more than sleep duration in the first 3 days. Hold the destination bedtime even if you only sleep 5 hours.
- Meal timing reinforces the shift. Eat on the destination schedule from the moment you board.
The protocol — pre-travel
Start shifting 1–3 days before departure. Move your sleep and wake time by 30–60 minutes per day toward the destination. Going east: earlier. Going west: later. This alone removes a day or two of recovery.
The protocol — in flight
Set your watch to destination time the moment you board. Hydrate. Skip alcohol — it wrecks deep sleep and dehydrates you. Sleep on the plane only if it's nighttime at your destination. Otherwise stay awake; a nap timed wrong locks in the old clock.
The protocol — at destination
Day 1 is the most important. Eat meals on local time. Get outside in the first few hours of local morning if flying east; avoid bright morning light and seek late-afternoon light if flying west. Hold a hard bedtime.
A 20-minute nap before 3pm is allowed if you're crashing. Anything longer or later and you'll be wired at midnight.
Melatonin: how to actually use it
Most over-the-counter melatonin is dosed 10–20× too high. The chronobiology literature is consistent: 0.3–0.5 mg taken about 30 minutes before your target destination bedtime is the sweet spot. Higher doses cause grogginess without working any better.
Frequently asked
How long does jet lag last?
Roughly 1 day per timezone crossed going east, 1 per 1.5 going west. With a plan, cut that in half.
Should I sleep on the plane?
Only if it's nighttime at your destination. Otherwise stay awake.
Is there a best app for jet lag?
The apps worth using build a personalized light, sleep, and caffeine schedule instead of generic tips. BioLag and Timeshifter are the two most-cited options.
What about ultra-long-haul (16+ hours)?
Split the recovery: shift 1–2 days pre-travel, then treat days 1–3 at destination as a continuation of the protocol — don't expect to be on local time by day 1.
Get your personalized plan
The free jet lag calculator builds a phased schedule for your specific flight — no sign-up required.