With aeroplane travel becoming more accessible and affordable, visiting your dream destination is a breeze, no matter how far away it may be. But, what if such a trip is derailed by feelings of lethargy, insomnia and indigestion? Such symptoms are prevalent in most air journeys and are typically a result of jet lag—a temporary sleep disorder that occurs when a person rapidly travels across three or more time zones. The severity of the jet lag increases with the number of time zones crossed.
Our body has an internal circadian clock that regulates our daily activities—including controlling when we sleep, wake, and feel hungry. A tiny region of the hypothalamus in the brain, called the suprachiasmatic nucleus (SCN), is the master regulator of this internal clock. The SCN is highly synchronised to the local time and takes cues, called zeitgebers or ‘time-givers’ from the external environment. Light is the principal zeitgeber which resets the SCN clock each day. Other zeitgebers which affect the body clock include social activity and eating habits.
As a result of travelling long distances, the internal body clock becomes out of sync with the local time at the destination. The SCN takes some time to adjust to the new schedule, resulting in jet lag and its symptoms. Aside from insomnia, lethargy and gastrointestinal disturbances, you may feel other symptoms including a loss of appetite, irritability, confusion and mild depression.
On the bright side, all of these symptoms are temporary and disappear once your SCN becomes synchronised to the new local time. However, can we prevent these symptoms from ruining the perfect vacation or an important business trip? Although there is no straightforward cure for the jet lag at the moment, a recent study provides hope. Researchers at the Washington University in St. Louis have identified a subset of SCN neurons that help the body clock readjust. Stimulating just 10% of these neurons, which produce a neurotransmitter called vasoactive intestinal polypeptide (VIP), enabled mice to overcome jet lag and quickly re-adjust their body clock to a new light/dark cycle.
Newer technologies in the design of aircraft are also improving the health of passengers during air travel. The Boeing 787 Dreamliner’ and the Airbus 350 both offer a smoother ride with higher cabin pressure and humidity. In-flight cabin lighting systems also help travellers adapt faster to a new time zone. While this is exciting progress, we are still a long way from abolishing the effects of jet lag.
There are also other strategies that can help minimise jet lag, including realignment of the body clock by strategically controlling the time and duration of exposure to light and adjusting sleep and exercise habits over a period of days. Depending on your flight timings and the time difference at your destination, slight modifications of your schedule can be made for a few days before and after your flight. There are plenty of online resources such as jetlagrooster and the jet lag advisor from British Airways that suggest ways to combat the effects of jet lag, specifically tailored to your travel schedule.
Besides, some individuals may find that taking small doses of melatonin, a hormone that makes you sleepy, along with other medication to counteract insomnia or daytime sleepiness, may be helpful. Other simple acts such as changing your watch to your destination time zone as soon as you board an aeroplane and keeping yourself hydrated throughout a long flight may help alleviate discomfort.
So on your next big vacation, be prepared and don’t let jet lag get the better of you.
Editor's note: A factual inaccuracy was corrected in this article. The Editors regret this mistake.