Ask any jetsetter what the worst aspect of long-distance travel is and the answer will most likely be jet lag. This is the range of symptoms experienced while your internal body clock adapts to being in a different time zone following a long flight.
It can disturb your sleep at night, make you feel drowsy and lethargic during the day, ruin your appetite and even cause digestion problems.
But what actually happens to our bodies when we cross international time zones and what can we do to ease the effects?
What causes jet lag?
All of our body’s functions have their own internal clocks (known as circadian rhythms) which interact with each other and are controlled by a ‘master’ 24-hour clock in a part of the brain called the hypothalamus. This master clock produces the hormone melatonin when it gets dark to make us feel drowsy and control our body temperature during sleep. So when we fly to a different time zone with different times for light and dark, these clocks go out of sync. Our bodies then have to try and catch up and re-establish their natural circadian rhythms.
It can take time to re-adjust to a new pattern of eating, sleeping and waking which is why jet lag can make us feel so sluggish. Also, according to a study published in the New England Journal of Medicine in 2007, the air pressure inside the aircraft lowers oxygen in the blood, making you feel uncomfortable and dehydrated which can exacerbate jet lag. As you get older, jet lag is likely to hit you harder and recovery may take a bit longer. (3)
Why is jet lag worse when you travel east?
It takes most people a few days to fully adjust, depending on how many time zones have been crossed and the direction in which you travel. Adjusting to travelling east is harder than westward travel because of the way our body clock functions.
This follows a roughly 24-hour cycle, so the body tries to compensate by contracting this to synchronise with the regular 24-hour sun cycle. So, when you travel west, you gain several hours and your body has extra time to make the adjustment. However when you travel east, your day is shortened and this makes the adjustment more difficult. (4)
How to cope with jet lag
In most cases, the symptoms pass after a few days without the need for treatment. Here are some practical steps you can take during your journey to ease the effects:
- It’s a good idea to try to sleep on the plane, if it’s nighttime where you’re going, or stay awake if it’s daytime but don’t worry if you can’t. It’s practically impossible to force yourself to go to sleep if you aren’t tired and attempts to make yourself fall asleep are likely to cause frustration. Just try to rest as much as you can.
- Drink water before, during and after your flight to counteract the effects of dehydration
- Avoid alcohol or caffeine a few hours before you plan to sleep. Alcohol or caffeine can disrupt sleep and may cause dehydration.
When you arrive
- Eat and sleep at the correct times for your new time zone, rather than the time you would usually eat and sleep at home
- Avoid having a nap as soon as you arrive even if you’re tired after a long flight. Staying active until bedtime will help your body adjust more quickly but don’t be tempted to put in a heavy gym session as soon as you arrive at your destination, as this could prevent nighttime sleep.
- Go outside. Natural daylight will help your body adjust to a new routine following most flights (2)
Are there any treatments for jet lag?
Some research has shown that taking a melatonin supplement could help to combat jet lag and aid sleep. However there’s not enough clinical evidence yet to say how effective this is. Melatonin is not currently licensed in the UK for the prevention of jet lag and there’s also insufficient evidence on the possible side effects for people taking blood thinning medicines such as warfarin. (5)
Visit LloydsPharmacy’s jet lag clinic for useful information and advice when flying.