As most frequent long-haul travellers know, generally, jetlag hits us worse when travelling east. Going west, trips are usually a little easier. Now researchers at the University of Maryland believe they’ve discovered why, and how to fight back against jetlag.
According to research carried out at the university, our bodies find it easier cope with a long day rather than a short one. Since travelling west moves us backwards in time – increasing the number of hours in our day – our bodies adjust better to the time difference than when travelling east. The shorter days caused by travelling east messes more with our body clocks.
To reach this conclusion, researchers created mathematical models of the area of the brain that regulates our circadian rhythm – our internal body clock that wakes us up and tells us it’s time to sleep. To see how the model brains responded to conditions similar to those of jetlag on increasingly longer trips, the researchers exposed the models to variations in daylight hours. They discovered that the neurons in the brains of humans suffering from jetlag fall out of sync. As they recover, they start to sync in time again. The recovery time varied depending on the distance and direction travelled. Travelling west over six time zones takes us about six days to recover, but travelling east over the same number of time zones, we need up to eight days for full recovery.
It appears that our brains respond better to the increased number of daylight hours when travelling west. However, when travelling east, we spend more waking hours in the dark, throwing our neurons increasingly out-of-whack and increasing recovery time. Michelle Girvan, a physics professor at the university, hopes their findings can help lead to better solutions for reducing the impact of jetlag. “Our model suggests that travellers should get as much exposure to the sunlight as possible on arriving at their destinations. If it’s cloud, artificial light can be helpful if used only during the daylight hours of the new time zone.” She goes on to suggest steps those travelling east can take to reduce the impact of jetlag. “For eastward travel across time zones, travellers may want try to shift their schedules a couple of hours forward in advance of their trip to limit disruption on their circadian cycle.”