The Science of Jet Lag Recovery
Understanding jet lag and how your circadian rhythm adjusts to new time zones.
Jet lag occurs because your body's internal clock (circadian rhythm) is still synced to your original time zone, while your physical environment demands that you sleep and wake according to a new schedule. Our Jet Lag Calculator estimates how long it takes your body to transition.
The General Jet Lag Formula
A well-known rule of thumb among sleep researchers and frequent flyers is that it takes roughly one day to recover for every timezone crossed. However, the direction you travel significantly impacts recovery.
Traveling Westward
When you fly West, you are "adding hours" to your day. This means you stay up later and sleep later. The human body adjusts to a lengthened day naturally, so westward recovery is generally faster (about 1 day per 1.5 timezones).
Traveling Eastward
When you fly East, you are "losing hours." You go to bed earlier and wake up earlier. Forcing the body to sleep before it is tired is very difficult, making eastward recovery slower (about 1 day per 1 timezone).
Frequently Asked Questions (FAQ)
What are the symptoms of Jet Lag?
Jet lag can cause daytime fatigue, difficulty sleeping at night, difficulty concentrating, mood changes, stomach problems (constipation or diarrhea), and a general feeling of not being well.
How can I beat Jet Lag faster?
Exposing yourself to bright, natural sunlight upon arrival helps reset your circadian rhythm. Melatonin supplements taken at night in your new timezone can successfully encourage your brain to sleep. Staying hydrated on your flight is also critical.
Do crossing North/South borders cause Jet Lag?
No. Jet lag is strictly related to crossing lines of longitude (East/West). Flying due South from New York to Bogota, Colombia involves crossing zero timezones, hence no jet lag—only potential travel fatigue.