Jet lag is the result of travelling through multiple time zones; this causes the body to have difficulty adjusting to a new schedule, as its circadian rhythms are likely to be still attuned to the previous time zone. For someone who has travelled through to a different time zone, their body may be feeling like it’s time to go to sleep, even though in the new time zone it is the middle of the day – or vice versa.
Jet lag only lasts a short while, but the severity of the temporary condition is often dependent on the direction in which you have travelled, as well as the number of different time zones that you have crossed. It is usually more difficult for people to adjust to a new time zone if they have travelled east, rather than west, and it generally takes a full day for the body clock to be able to adjust completely to the new time zone.
People who are suffering from jet lag may find it difficult to function at their normal capacity. They may often find it hard to stay awake, and suffer a lack of alertness when they attempt to sightsee, socialise or work. Jet lag can affect people of all ages, although it is more likely to be of greater severity in older travellers, who are also likely to need more time to adjust. Rapid shifts in time zones can actually make it easier for some people to adjust. Regular business travellers, pilots and flight attendants inevitably suffer from jet lag more than those for whom travelling between time zones is a much rarer occurrence. Jet lag can be made worse by a number of factors, such as:
- Loss of sleep due to travelling
- Alcohol and caffeine use
- Poor air quality or air pressure
- A long time spent in an awkward or uncomfortable posture, e.g. sitting on a plane
Circadian rhythms are the internal body clock that tells people when they should be alert or sleepy, and jet lag is a sleep disorder that affects circadian rhythms. These rhythms operate in a cycle that runs approximately 24 hours, with the body making use of sunlight to work out how much of the hormone melatonin it needs to produce, which promotes sleep. The production of melatonin tends to be much higher in the evening and much lower during daytime hours, but someone who has travelled through multiple time zones will find their circadian rhythms disrupted and the body clock becomes confused.
People expect to be alert and awake during daytime, but jet lag can cause fatigue. The symptoms associated with the disorder tend to be longer lasting and even more severe the longer you have been travelling, particularly in an eastward direction. Symptoms often connected with jet lag include:
- Difficulty falling asleep
- Inability to function normally in daytime hours
- Stomach upset
- Menstrual symptoms (women)
- Feelings of tiredness or disorientation
- Mild sickness
If you have travelled across at least two time zones by plane, you feel sick or have an upset stomach, and are having trouble functioning in a normal manner within a day or so after that journey, it is highly likely that you are suffering from jet lag. Try and adjust your sleep schedule, and it will usually pass in a few days. However, if you travel between time zones regularly and are continuing to struggle with the issue, it may be a good idea to talk to your GP or a travel clinic.
Dealing with jet lag
There are behavioural adjustments and natural remedies that can help you to deal with jet lag after travel. One method is to plan ahead and begin slowly changing your sleeping and waking hours in the weeks leading up to the trip. By the time you make your journey, your schedule will already be close to that of your destination. Another good tip is to go out and get plenty of daylight after arriving, as sunshine is an excellent tool to get your body adjusted. Bright light therapy and melatonin supplements can also be good solutions. Moderate exercise can help with adjustment, as can cutting down on alcohol and caffeine.