What is jet lag?

Spending a few hours travelling by air across several time zones can make you feel low, tired and lethargic. This is called jet lag — that less than uplifting response to time zone changes that your body doesn't appreciate and may have trouble adjusting to.

What are the symptoms of jet lag?

  • Daytime tiredness.
  • Difficulty in sleeping.
  • Irritability or anxiety.
  • Difficulty in concentrating and making decisions.
  • Loss of appetite and nausea.
  • Constipation.
  • Headache.
  • A general feeling of being unwell.

What causes jet lag?

Your body clock operates on a 24-hour cycle that keeps time by stimuli such as eating and sleeping patterns and reactions to light and darkness. Melatonin, a sleep-promoting hormone, plays a major role in regulating body rhythms. Melatonin is released from a gland in your brain (the pineal gland) when it is dark, and melatonin release is switched off when it gets light. Changing time zones changes your normal rhythm, knocking your body clock off balance.

The more time zones you cross, the worse your jet lag will be. Travelling east usually requires a greater adjustment as you move forward in time.

As a rule of thumb, it takes about one day to recover for each time zone you go through.

Your body may struggle to cope with the changes in time zones and you may experience temporary insomnia, fatigue, irritability or anxiety. Meanwhile, your bowel habits may change and constipation can be a problem.

What you can do to help treat jet lag

  • Book your flight so that you arrive at night. This helps your body adjust to the changes in time zones.
  • If possible, have a stopover during a long trip.
  • Avoid in-flight alcohol. Airline cabins are extremely dry, making the body feel dehydrated, which can worsen jet lag. Alcohol adds to your body's dehydration. It is better to drink fruit juices and water frequently.
  • Avoid caffeine on the flight (it can cause dehydration and add to feelings of anxiety).
  • If possible, adapt to the local schedule immediately — for example, if you arrive at noon local time (but it is 6am your time) eat lunch, not breakfast.
  • At your destination, try to get out into the sunlight during the daytime. Exposure to light keeps your biological clock in a stimulated and awake state.
  • Try to exercise; if you usually go jogging you should continue to do so at your destination. This helps keep you alert during waking hours and tires your body, making it ready for rest and sleep at night.
  • Don't nap during the day; it will just delay your adjustment to the new time zone.
  • Seek medical advice regarding jet lag and any medicines that you take. Remember to take medicines at your normal ‘home’ time or adjust dosages to suit local time.

Medicines for jet lag

Sleeping tablets may help you to sleep during flights and can be used at bedtime when you arrive at your destination for up to 3 subsequent nights. Sleeping tablets are not suitable for all travellers — you should check with your doctor.

Medicine containing melatonin has been used as a treatment for jet lag, but there is conflicting evidence for its effectiveness. Melatonin is not suitable for people with certain medical conditions and it can interfere with other medicines. In Australia, it is currently only available on prescription for the treatment of insomnia in adults aged 55 years or older.

Last Reviewed: 20/01/2010

myDr. Adapted from original material sourced from MediMedia.



References

1. Jet lag [revised October 2008]. In: eTG complete [Internet]. Melbourne: Therapeutic Guidelines Limited; 2010 Mar (Accessed 2010 May 4.) http://www.tg.org.au/
2. Herxheimer A. Jet lag. Clinical Evidence [online] 2008 [cited Dec 4]. URL: http://clinicalevidence.bmj.com/ (accessed 2010. May 4)
3. Mayo Clinic [website]. Jet lag disorder (updated 2008, Jul 11). Available at: http://www.mayoclinic.com/health/jet-lag/DS01085 (accessed 2010, May 4)
4. Circadin Prescribing Information. RAD Data. Accessed via eMIMS. Date of TGA approved information: 15/12/2009