I am writing this in the chilly northern hemisphere, having hauled my three children halfway across the world to visit my Yorkshire family. It took us 40 hours to get from Hataitai to this remote hillside farm, and nearly a week to get over the jet lag.
After several nights of appalling sleep, interrupted by one or the other of my offspring appearing at my bedside wide awake at 3am, I decided to do some research into melatonin, in the hope that our return to Wellington may be more restful.
Jet lag commonly affects travellers who cross several time zones, and is more severe the greater the number of zones crossed. It results from a discrepancy between the body's internal rhythm (or body clock), and the day-night cycle at the destination.
It causes tiredness, insomnia, impaired co-ordination, poor psychological functioning, and nausea. It also results in numerous lost or unproductive working hours for business travellers. It is compounded if you consume alcohol or caffeine on board, and if you miss a lot of sleep on an overnight flight.
Melatonin is a hormone, released in the body by the pineal gland, a pea-sized gland in the middle of the brain. It plays a central part in regulating body rhythms. During the day the pineal gland is inactive. However, as night approaches, the pineal gland is activated and starts to produce melatonin. Blood levels of melatonin rise sharply, making you increasingly sleepy. Come morning, the pineal gland shuts down again, cutting off the melatonin and allowing us to wake up.
As jet lag is caused by the body confusing day and night, it makes sense that taking a supplement of melatonin might be useful. So what is the evidence for this, and how effective is it thought to be?
A Cochrane review looking at melatonin as a treatment for jet lag is very encouraging. It found that if taken close to bedtime at the target destination, melatonin is highly effective at preventing jet lag in travellers crossing five or more time zones. The benefit was greatest for east-bound flights, and for flights crossing a greater number of time zones. The timing of taking melatonin is important - it should be given 30 minutes to an hour before bedtime in the new country. If taken too early, it can cause daytime sleepiness and delay adaptation to the local time zone.
The studies looked at doses from 0.5mg to 5mg, and found that the higher doses were likely to be more effective. Recommendations vary, but I would suggest trying 1mg to 5mg initially. It is important that slow-release formulations are not used as these may make your symptoms worse. Again, there are no hard and fast rules for how long you should take melatonin, but using it for the first three nights in the new country appears to be the norm.
As yet, there do not appear to be any major risks for people using melatonin in the short term - that is a few days at a time. However, it is not recommended for use in pregnant or breast-feeding women, and there are also concerns about its use in epilepsy.
It is best avoided by these groups until it has been more extensively tested. It is also not recommended for use in most children, with the exception of certain groups who have sleep disorders or underlying medical conditions.
There have been occasional reports of minor side effects, including headache, dizziness, stomach cramps, temporary depression or irritability, and daytime drowsiness. Further research will help ascertain how common these side effects are.
Melatonin, unfortunately, is not going to be an option for everyone. If you are taking certain medications (including warfarin, sedatives, or blood pressure tablets), it is wise to check with your doctor or pharmacist first.
The cost can be prohibitive too - as it is not yet funded in New Zealand, it requires a doctor's prescription and can cost about $1 a tablet.
However, if you are planning a 40-hour trip to Yorkshire in the near future, I would recommend you pack some in your hand luggage. I won't be dosing up my offspring when we return to Wellington in a month, but I will be trying it myself.
Cathy Stephenson is a general practitioner, medical forensic examiner and mother of three.
- The Dominion Post
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