Jet Lag Light-Timing Planner
Beat jet lag with the strongest circadian lever there is: light. Enter your trip to see which way your clock needs to shift, and when to seek and avoid bright light.
Estimated CBTmin (clock pivot) ≈ 05:00. Each day, nudge the windows ~1 h in your shift direction.
Light windows are anchored to your estimated CBTmin (≈ 2 h before wake) and shown on your home clock for the first day; advance them about 1 h/day (eastward) or delay ~1.5 h/day (westward) as you adapt. Educational planning aid, not medical advice — melatonin, meal timing and sleep scheduling also help.
Land already adjusting
ONDA Life tracks how travel hits your sleep, HRV and recovery — and turns light, melatonin and meal timing into a day-by-day plan so you arrive closer to local time.
Download ONDA Life on the App Store →Common questions
How does light help with jet lag?
Light is the most powerful signal for resetting your body clock. Getting bright light at the right time — and crucially, avoiding it at the wrong time — shifts your circadian rhythm toward the destination time zone. Mistimed light pushes the clock the wrong way and makes jet lag worse, which is why timing matters more than simply "getting sunlight".
Why is flying east worse than flying west?
Flying east requires advancing your clock (going to sleep and waking earlier), but the human clock runs slightly longer than 24 hours, so it naturally prefers to delay. Advancing is harder and slower — about 1 hour per day — while delaying (flying west) goes at roughly 1.5 hours per day. That is why westward trips usually feel easier to recover from.
What is CBTmin and why does it matter?
CBTmin is your core-body-temperature minimum — the coldest point of your daily cycle, which falls roughly 2 hours before your usual wake time. It is the pivot for light timing: light in the hours after CBTmin advances your clock, while light in the hours before it delays your clock. The planner uses your wake time to estimate it.
How many days does it take to get over jet lag?
A common rule of thumb is about one day per time zone crossed when flying east, and a bit faster flying west. Well-timed light (and avoiding wrong-time light) can speed this up; doing nothing, or getting light at the wrong time, slows it down. For very long eastward trips the body sometimes adjusts by delaying "the long way round" instead.
Does this replace melatonin or sleep medication?
No. This is a light-timing planner — light is the strongest lever, but correctly timed melatonin, strategic napping, meal timing and good sleep hygiene all help too. It is an educational aid, not medical advice; if you fly frequently or have a sleep disorder, talk to a clinician about a tailored protocol.