Why jet lag happens
Your body clock runs on roughly a 24-hour rhythm set mainly by light. When you fly across time zones, the clock on the wall jumps but your body clock doesn’t, so you feel sleepy, hungry and alert at the wrong times. According to the CDC, the body clock adjusts by about 1 hour a day after flying east and about 1.5 hours a day after flying west, which is why flying east usually feels worse.
How to reduce jet lag
- Shift your sleep before you go. For 2 to 3 days before you fly, move your bedtime and wake-up time 1 hour a day: earlier if you are flying east, later if you are flying west.
- Use light at the right time. After flying east, get bright light in the morning and avoid it in the evening. After flying west, get light in the evening and avoid bright light early in the morning.
- Switch to local time quickly. Eat meals and go to bed on local time from your first day.
- Melatonin may help. The CDC notes that 0.5 to 5 mg of melatonin, taken at the right time, can help some travellers. Talk to a doctor or pharmacist first, especially if you take other medicines.
- Short trips: if you are away for 2 days or less, it may be better to stay on home time.
Check the exact time difference for any city on our sister site, ClockNow’s time zone converter.
Frequently asked questions
How long does jet lag last?
Roughly 1 day for each time zone crossed when flying east, and a little less when flying west. A 8-hour time difference eastward can take about a week to fully adjust.
Is jet lag worse flying east or west?
East. Flying east means going to bed earlier than your body clock wants, which is harder than staying up later.
Should I sleep on the plane?
Sleep on the plane if it is night-time at your destination. If it is daytime there, try to stay awake, or take only short naps.
For general information only, not medical advice. If you often feel tired despite enough sleep, snore loudly, or have trouble sleeping most nights, talk to a doctor.