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Your body's biological clock can become 'desynchronised' when you travel rapidly through several time zones. If a flight crosses more than 3 time zones, jet lag may be a problem. It tends to cause more symptoms if you are older, as the body clock takes longer to reset. The effects are worse when you are flying east than when flying west, as when travelling west the body treats it
 as a “long day”, while in effect when travelling east the movement across time zones is in the opposite direction to the body clock.

Our internal clock can more easily extend our day, but it finds it very difficult to reduce the hours in our day.

Jet lag may affect physical and mental performance. Symptoms include:

It may take a few days to acclimatise to a new time zone and you need to think ahead to synchronise your body clock with the time zone to which you are travelling. If possible, try going to bed earlier for a couple of nights before you travel east, and later before travelling westbound.

Short stays

For short stays (less than 48 hours) across multiple time zones it is unlikely your body clock will adjsut, so some people choose to maintain “home time” rather than try to get used to local time. Tips from British Airways for keeping your body clock on home time-

Tips to minimise jet lag for longer stays:

  1. Drink plenty of non-alcoholic drinks (water is best) before, during and after the flight to prevent dehydration
  2. Avoid alcohol
  1. For longer stays, adjust your habits as soon as possible to the new local time and avoid napping during the daytime. Short acting sleeping tablets may be useful at first to promote night time sleep

How long will it last?

Allow at least one day to recover for every hour of time difference travelled westwards, and a day and a half to recover for every hour of time difference travelled eastwards. Many people, especially older people, may find that it takes longer for symptoms to resolve.


Some studies have shown that taking this hormone may improve jet lag symptoms, but further investigation is required before its use is recommended – research evidence appears to be mixed, and a small number of people who take it report worsening symptoms. It is only available as an unlicenced prescription in the UK and needs to be taken in the correct dose and timing for your individual circumstances to be effective– if you plan to take it, you may be best to consult a travel health or sleep specialist. In some countries, where it is available over the counter, the purity and safety of melatonin products may be uncertain.