If you’ve ever been on a long-haul flight, or you’re someone who has racked up thousands of frequent flyer miles, you are likely to have experienced the phenomenon of ‘jet lag’, which can affect your sleep patterns and daytime alertness. But what exactly is it? And can we avoid it?
Jet lag is a type of fatigue caused by travelling abruptly across different time zones. The body tends to need anywhere from a few days to a few weeks to acclimatise to the new time zone – a good rule of thumb is one day for each hour of time-zone changes.
Many of our bodily responses such as our temperature, heart rate and digestion are timed to a 24-hour internal clock. The changing rate of activity over this period is called the ‘circadian rhythm’ and travelling to a different time zone disrupts this rhythm. Interestingly, your body clock is less confused if you travel westward, say from Sydney to London. This is because travelling west ‘prolongs’ the body clock’s experience of its normal day to night cycle.
While many seasoned travellers cite various strategies such as fasting or eating complicated diets, there is no evidence these strategies work.
A dose of daylight: Alexandra Bhatti says once you arrive in your destinatiion, sunlight can help 'reset' your body clock.
Strategies useful for reducing the impact of jet lag include getting enough sleep prior to travelling, drinking plenty of water and limiting alcohol and caffeine during a long flight. Once in your new time zone it’s also helpful to maximise exposure to daylight to ‘reset’ your body clock and adjust.
Medicines aren’t usually needed for jet lag. There have been reports of some benefits from taking the hormone melatonin or very short-acting sleeping tablets, however doing so should be discussed with your doctor. Generally speaking, melatonin supplements aren’t recommended for jet lag because there isn’t enough evidence they work. Sleeping tablets can be effective but can impair concentration and alertness the next day and issues of dependence may arise.
Early stage research out of Harvard University has indicated that the drug tasimelteon may have a future role in the treatment of jet lag. This was based on studies that found the drug improved sleep quality and time spent asleep in healthy people whose sleep pattern had been brought forward by five hours. In saying this, there were limitations to the studies and more research is needed to draw firm conclusions.
Armed with a handful of strategies for how to best avoid jet lag, the next question is, which holiday should you book?
Dr Alexandra Bhatti is a lecturer in the Master of Public Health program within the Department of Health Sciences.
