Jet lag

Jet lag

What is jet lag?

Jet lag is a disturbed pattern of the sleep and wakefulness cycle, contributing to fatigue, disorientation, irrationality and lower resistance to disease or illness.

What are the symptoms of jet lag?

Symptoms include being worn out and tired for days after arriving, generally accompanied by a lack of concentration and motivation, especially for any activity that requires effort or skill, such as driving, reading or discussing a business deal. Dehydration can cause headaches, dry skin and nasal irritation and make you more susceptible to any colds, coughs, sore throats and flu that are floating round in the aircraft.

What causes jet lag?

The main, but not the only cause of jet lag is crossing time zones. Your body clock is regulated by a small cluster of brain cells that controls the timing of biological functions (circadian rhythms), including when you eat and sleep. During a long haul flight your inbuilt circadian rhythms have been disturbed and it can take many days for the body to readjust to the new time zone. This can lead to nausea, indigestion, fatigue or insomnia.

Who gets jet lag?

Almost everyone on a long flight suffers jet lag to some degree. A major US study showed 94% of long haul travellers experience it. A New Zealand study showed 96% of flight attendants suffer from it. Usually going east is worse than going west. Most travellers think daytime flights cause less jet lag and more daytime long haul flights are being added by major airlines. The number of intermediate stops is also a factor, as each stop is accompanied by changes in cabin pressure which aggravates jet lag.

Children under three don't seem to suffer jet lag badly as they are more adaptive and less set in their ways. Adults who adjust readily to changes of routine also seem less susceptible to jet lag. People who normally stick to a rigid daily routine and who are bothered by changes to routine, are often the worst sufferers. People who sleep easily can also cope better with the adjustment.

How long does it take to recover from jet lag?

NASA estimates you need one day for every time zone crossed to regain normal rhythm and energy levels. A five-hour time difference means you will require five days to get back to normal.

How can I avoid jet lag?

Jet lag is a physical, not psychological, condition, and no single solution will work for everyone. Stay on home time if you won't be gone more than 25 hours; there's no point having to readjust twice in two days. If your trip will be longer, go by local time. Eventually your body will realise the difference and synchronise its clock with the new location.


  • If you are over-tired, excited, stressed, nervous, or hung-over before the flight, you are setting yourself up for a good dose of jet lag.
  • Sleep is one of the best ways to minimise jet lag. Just getting a good night's rest the night before a long trip can help you feel better upon arrival. Allow yourself unrestricted sleep for three nights prior to departure, sleeping through until you wake naturally. This means avoiding being woken by alarm clocks or phone calls.
  • Before departing, make sure you have all your affairs, business and personal, in order. Ensure you are not stressed-out with excitement or worry, and not tired or hung-over from a function the night before.
  • Get plenty of exercise in the days prior to departure and try to avoid illness such as the flu, colds and so on.
  • If you have a cold, flying will probably make it worse. Consider delaying the trip.
  • Try and book on a direct flight that departs during daylight.
  • If you must fly at night, consider taking a short-acting sleeping tablet to assist sleep on board the plane. These are available on prescription only.

During the flight:

  • Fatigue is the first sign of dehydration. The dry air on board an aircraft can cause headaches, dry skin and dry nasal and throat membranes, creating the conditions for catching colds, coughs, sore throats or the flu. Providing a constant supply of fresh air in the cabin costs the airlines money and some airlines are more willing to oblige than others. The air supply in business and first-class is often better than in economy class. A lack of good air helps make you tired and irritable and can cause headaches. Sometimes if you ask the flight attendants to turn up the fresh air they will do so.
  • Try to drink at least eight ounces of fluids for every hour you are up in the air. Water is better than coffee, tea and fruit juices. Go easy on acidic beverages.
  • Avoid alcohol, especially if you intend taking sleeping tablets. Alcohol not only is useless in combating dehydration, but the impact of alcohol on the body is 2-3 times more potent when you're flying.
  • Get into the rhythm of your destination as quickly as possible: set your watch to the time at your destination once aboard the aircraft, and then take meals and sleep accordingly.
  • Melatonin, which is available in health shops in some countries, in a dose of 3mg at bedtime can help rest. Be warned that it can cause drowsiness the following day.
  • Go easy on the frequent meals served in-flight. You don't need them. Sitting in a cramped position puts extra pressure on your stomach. High-protein foods such as meat and green vegetables give your body long-lasting energy, as opposed to the quick burst of sugar you get from sweets. Be wary of the risky foods served on some airlines in certain parts of the world, including salads and cold meat and fish.
  • Blindfolds, ear plugs, neck-rests and blow-up pillows are all useful in helping you get quality sleep while flying.
  • Kick your shoes off to ease pressure on the feet (some airlines provide soft sock-like slippers and many experienced travellers carry their own). At a cruising altitude of near 30,000 feet the aircraft is pressurised to near 8,000 feet. Unless you live near 8,000 feet and are acclimatised to this pressure you may suffer from swelling, tiredness and lethargy.
  • Lack of exercise is one of the worst aspects of long-haul flying. Do stretching exercises. Get off the plane if possible at stopovers. Walking and exercise helps to reduce the possibilities of blood clots and associated trauma.
  • If there is an opportunity during a ground stop, take a shower - it freshens you, tones the muscles and gets the blood moving again.
  • If possible on stopovers, you should spend time outdoors. Normal indoor lighting is not bright enough to reset the biological clock.

On arrival:

  • If you feel sleepy when you arrive, take a short nap if you can but then get out and be active in your new environment.
  • If possible get exposure to sunlight during the day, with exercise in the mornings but not the afternoons.
  • Take drinks containing caffeine such as coffee, tea, cola drinks and chocolate in the mornings at your destination, but avoid them in the afternoons and evenings.

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