Jet lag: Why does it happen and what you can do about it

Home Blog Article Jet lag: Why does it happen and what you can do about it

Jet lag: Why does it happen and what you can do about it

What is jet lag?

Jet lag disrupts your body clock because of the rapid shift to a new time zone. It occurs because your body cannot immediately shift to a new time zone, and your body clock requires some time to adjust. During this time, the symptoms of jet lag can make you feel drowsy during the day, sleepless at night, general fatigue, feeling unwell and digestion disturbances.

How does my body adjust to a new time zone?

The main clock in the brain influences your sleep and wake pattern, this clock is set by when it’s light and dark out. Light is a major signal for our brain to be awake and darkness to be asleep. That said, this rhythm is fairly flexible, which allows us to adjust to new time zones.

Once you cross several time zones, your body needs time to adjust to the new light and dark schedule. Your circadian rhythm can only change about 1 hour every 24 hours. So the more time zones you cross, the more days you need to establish status quo.  


Whenever you fly, decide whether it’s necessary to adjust to a new time zone. If it’s a short trip (less than 3 days) then it’s much easier to stick to your home rhythm. However, this means you’ll need to keep a rigorous schedule of sleeping, eating and having social interactions on your home time zone. When you get back to your home time zone, you won’t have any jet lag!

West is Best, East is Beast

For most people, the jet lag from flying West is less severe. This is because it’s easier to fall asleep a little later than falling asleep earlier, therefore jet lag symptoms are worse when flying East.

There are different ways you can minimise discomfort from jet lag, such as shifting your rhythm faster with melatonin and light exposure at the right times. The tips below are to help you prepare for your trip a couple of days before, while you’re still in your home time zone!

When flying West: 

  • Adjust your rhythm by going to bed 1-2 hours later than your usual bedtime
  • Get light in the evening as it will keep you awake and help you stay up later.
  • Alternatively, use the extra time for a work-out!

When flying East

  • Adjust your rhythm by going to sleep 0.5-1 hour earlier than your usual bedtime
  • Get light early in the morning.
  • To help going to sleep about 1 hour earlier, take melatonin 0.5 mg in the late afternoon or early evening to shift your rhythm.

Caution about melatonin use:

  • You don’t need high dosages, only 0.5 mg. Make sure to check the packaging for the correct concentration, often melatonin is sold in high dosages.
  • Only use melatonin for jet lag. It’s not something to use to fall asleep every night. Scientific research shows it helps to shift your rhythm, which isn’t what you need to do every night.
  • Don’t get slow release melatonin, research shows a faster peak works better.

More tips to battle jet lag!

  1. Avoid drinking alcohol and coffee before your flight, both drinks will disrupt your sleep rhythm. Drink lots of water to stay hydrated.
  2. Eat at times that correspond to the time zone you prefer your rhythm to be in.
  3. Your brain uses sunlight to detect when it’s best for you to sleep, so pick flights which land during the day. This will help you stay awake and get used to a new time zone.

References: Burgess and Eastman. (2009). How to travel the world without jetlag. Sleep Med Clin. 2009; 4(2): 241–255.