In the last blog post I wrote about whether running reduces jet lag, but supported my discussion with animal-based scientific studies, including one undertaken in hamsters and one in mice. Since then I have found a good review of how athletes can reduce jet lag after travel. Is running upon arrival at your destination included?
A systematic review was published three years ago by Lee and Galvez (2012), with studies conducted between 1980 and 2012 reviewed for inclusion. The first part of the paper examines what risk factors there are for jet lag, as obviously the extent of jet lag you experience varies depending on a number of factors.
Factors associated with jet lag
- Sleeping habits - those with more rigid sleeping schedules tend to experience worse jet lag
- Chronotypes (e.g. are you a "morning person") - morning people have less difficulty flying east and more difficulty flying west
- Physical fitness - the fitter you are, the faster you adjust to a new time zone
- Travel direction - flying east is worse than west
- Number of time zones - the more time zones you fly across the longer it takes. There is a rough rule that says it is 1 day to adjust per time zone
- Age - a bit inconclusive, but worse if you´re over 60 years
- Time of arrival - arriving at midday means you adjust quicker than arriving in the morning
Treatment for jet lag
There are pharmaceutical and non-pharmaceutical treatments for reducing jet lag, but the first question you should ask is, do I want to adjust to this time zone? For short trips, 1-3 days, athletes are usually advised against trying to adjust fully to the new time zone.
For trips longer than 3 days there are three types of pharmaceutical treatments:
Written about at least three times in previous blogs, melatonin is intimately involved in the circadian rhythm and you can buy it as a supplement (in some countries you will need a prescription). It has shown to be effective in reducing jet lag, and can be taken at night when travelling east and in the early morning when travelling west. It can give you a bit of a "hangover" when you first wake up after taking it at night.
2. Sleeping tablets
They are effective for sleeping and may limit the "hangover" effect experienced the next day. however their effect on performance the next day has been questioned. But generally, selective usage of short acting sleeping tablets has been recommended for athletes who previously tolerated the medication well and have persistent insomnia.
There is benefit of their use (prescription stimulants) in terms of maintaining alertness during the day, however most are not recommended for athletes as they are banned. Caffeine has been shown to be beneficial, especially when used in the morning. More care should be taken when using caffeine in the afternoon though, as it may impact that night´s sleep.
1. Bright light therapy
Exposure to bright light of adequate intensity and duration can advance or delay circadian rhythms, depending on the timing of exposure. Bright light exposure in the morning will advance the body clock, while exposure in the late evening will delay it.
Diet can influence how quickly you adjust to your new time zone. Ingesting a high-protein breakfast will promote arousal and wakefulness in the morning, and a high-carbohydrate dinner will promote sleepiness in the evening. This form of dieting has been used by military personnel to reduce jet lag, however is not generally recommended for athletes who need strict diets to meet activity needs. Maintaining hydration while flying has also been shown to be important.
Shifting your current time zone sleeping patterns 1-2 hours before you fly in the direction of the new time zone can help reduce jet lag once you arrive. Start adjusting two to three days early and make sure you are well rested as you get on the plane.
The one you have been waiting for. As discussed in part 1 of this blog, exercise affects the circadian rhythms of core temperature and heart rate. Therefore it has been proposed that it may ameliorate jet lag. Unfortunately a timed exercise to resynchronise the sleep cycles of marathon runners did not support this theory. Another review also concluded that exercise cannot reliably shift the circadian rhythms, although it may help maintain arousal levels after travel.
So what can we conclude from all this... it seems there are plenty of things that can be done before, during and after travel to make the readjustment easier, and although running may help a bit (by getting you outside and exposing you to light), as well as with maintaining alertness, etc., unfortunately it is not the golden bullet you are looking for.
Reference: Lee and Galvez (2012) Jet lag in Athletes. Sports Health. 2012 May; 4(3): 211–216.