Coping with a disrupted circadian rhythm

With the holiday season upon us, many Brits will be jetting off in search of adventure. Florence Roberts-Graham has been looking into how the body reacts to traveling long distances and what holidaymakers can do to lessen the impact.

What is jet lag?

Jet lag is the effect of a sudden switch of time zones in air travel. This often results in an unpleasant feeling of extreme tiredness, depression and slowed mental and physical reactions andjetlag_caribb sometimes sickness.

Why might people suffer from Jet Lag?

Jet lag occurs when you fly east to west (easier to adjust) or west to east (harder to adjust). You don’t get jet lag when you fly north to south or vice-versa. This is because you only switch time zones when flying horizontally across the globe. The actual jet lag is caused by the dislocation between the body clock and local zeitgebers (external or environmental cue of time and date e.g. watches). Our biological rhythms are not equipped to cope with sudden and large changes.

Other factors affecting the severity of Jet Lag

Firstly the number of times zones crossed can have an effect as the more you pass the more dislocation your body will feel between the body clock and local zeitgebers. Secondly age. Sack et al (2007) found that jet lag decreases with age.

Individual differences mean some people might suffer awfully with jet lag even just crossing one time zone, but others might not be affected them at all, this is called “phase tolerance”.

Reducing jet lag

Even though we can’t do a lot to avoid jet lag, there are a few things that might help to reduce it.

  • Sleeping well before your flight is always a good idea as you might struggle to sleep at a different time once the time zone has changed.
  • Adjust flight behaviour to time zone of destination this is to slowly prepare yourself as much as you can so it’s not such a sudden change.
  • Avoid caffeine or alcohol
  • On arrival, use and adjust to local zeitgebers
  • Go out in the morning daylight as soon as possible, sunlight is very effective at resynchronising body clock.

Evidence found that also reduces jet lag

Beaumont et al (2004) found that melatonin given at bedtime three days before travel and for five days after arrival significantly reduced the symptoms of jet lag.