International travel can result in:
- Simple travel fatigue - no time change.
- Jet lag - travel across time zones. Disturbed sleep, poor concentration, irritability & difficulty in getting to sleep and staying asleep in the new time zone Little research has been done into simple travel fatigue but most travellers know what works best for them, including careful planning to reduce stress as far as possible, a good night's sleep before travel and maintaining personal fitness. Caffeine and alcohol have been implicated in worsening travel fatigue but there is no conclusive evidence that small amounts have a significant effect. Simple food, exercises in flight and staying awake by day help most people. Jet lag results from the body's delay in resetting circadian rhythms to the new time zone. Cognitive performance as well as sleep are affected for several days after arrival. Adjusting as far as possible to rising and sleeping times at your destination is effective but often impractical. Easier, and surprisingly effective are light exposure and moderate exercise during what will be daylight hours at destination. The place of Melatonin in jet lag is now a great deal clearer than 5 years ago and we are now able to recommend it though still unable to prescribe it in Europe. The Cochrane Collaboration recently reviewed 10 well conducted studies on the effects of Melatonin on sleep at destination and subsequent mental capacity. Eight of these trials showed positive benefits for low dose Melatonin. One of these demonstrated half the number of errors on rising the following day in those taking Melatonin compared to placebo. Doses of between 0.5 mg and 5 mg were effective; not surprisingly doses towards the upper end of this range were more effective than lower doses. Exceeding 5 mg did not confer additional advantages and very high doses - not included in the Cochrane review - have been associated with hangover effects. Regular-release or fast-release preparations were more effective than slow release formulations. Perhaps surprisingly side effects have not been studied within the discipline of a randomised trial. The doses given above, however appear to be safe and doses even 3,000 times higher have resulted in only minor adverse affects. None-the-less Melatonin will be best avoided in pregnancy, during breast feeding, in children and in those with epilepsy or who are taking blood thinning medications other than Aspirin. Melatonin is sold over-the-counter as a herbal remedy in the USA and Singapore but is registered as a medication in the UK and much of Europe. Its low cost and ease of availability in the US has given pharmaceutical companies little incentive to carry out the costly toxicological studies needed to produce it as a medication in Europe. Outside of the US and Singapore it is therefore available only via the internet where quality is not regulated and cannot be assured. Given its effectiveness and apparent safety, however it seems to reasonable to follow the advice of Prof. Herxheimer from the Cochrane Collaboration: "It seems advisable to buy [Melatonin] from a large reputable pharmacy chain [in the US or via the internet] and hope for the best".
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