|
In many ways, air travel has had positive influences on the quality of our lives. For our bodies, however, the effects of air travel are not always so positive. Repeated studies show at least 90 percent of long-distance travelers experience some degree of jet lag.
Jet lag is a term used to describe the fuzzy, out-of-sorts feeling that often follows a long flight, especially when the traveler has passed through a different time zone. The symptoms of jet lag vary but often include: daytime drowsiness, fatigue, irritability, difficulty concentrating, headaches, insomnia and swelling of the extremities. The symptoms can range from mild to severe and, in some cases, significantly impair the post-flight performance of business travelers, sports competitors and general long-distance travelers.
The number of time zones travelers cross is a major factor in assessing jet lag. Studies show people can suffer jet lag just crossing the United States (a three-hour time change) but may not be affected by a north-south flight of the same duration. Crossing time zones plays havoc with your body clock mechanism, also called the circadian rhythm. The circadian rhythm is controlled by a small part of the hypothalamus in the brain that processes nerve signals. The body clock is programmed for regular cycles of daylight and darkness. This cycle is disturbed and then gets out of sync by changing time zones. Depending on the number of time zones that have been crossed, it may take several days to restore the circadian rhythm.
Other in-flight factors that contribute to jet lag include:
Cabin pressure
When the cruising altitude reaches 30,000 feet, the aircraft is pressurized to about 8,000 feet. Unless you are accustomed to this altitude, you may develop lethargy and suffer from swelling of the extremities.
Stale air and lack of humidity
The aircraft environment is typically very dry, with the humidity ranging from 10 percent to 20 percent. This can result in dehydration for the passengers. The lack of humidity also can cause drying of skin, eyes and airway passages. It can especially be a problem for people with airway disease, such as asthma.
Pre-flight condition
If you are hung-over, sleep-deprived, run down or just plain worn out before you begin your travel, chances are greater that you will be more susceptible to jet lag.
Although jet lag cannot be cured, there are some tips that may help to reduce the severity of symptoms. Consider the following before, during or after your next scheduled air flight:
- Avoid alcohol and caffeine just before and during your flight. Both alcohol and caffeine have diuretic properties, which means that they cause you to lose water and make you dehydrated. Also, alcohol causes drowsiness and can contribute to the sluggish feeling experienced by many travelers.
- Reset your watch to the time zone that you are traveling to. This lets you start thinking according to your arrival destination's local time before you even arrive.
- Create as dark an environment on the plane as possible. Bright lights have a strong effect on a person's body clock. Use eyeshades and earplugs to help block out the in-flight distractions and convince your body that it is dark. Closing the window shade and turning off the overhead cabin lights may also help. Sleep on the plane if your flight has an early morning arrival time.
- Wear comfortable clothing and shoes. If you experience mild swelling, it will help to have loose-fitting clothing and comfortable shoes.
- Get adequate rest before your flight. By starting your trip well-rested, you will not be playing as much "catch-up" when you arrive at your destination. Likewise, when you return, try to schedule a day of rest before returning to work.
- Walk around and do isometric exercises (simply contract and relax as many muscle groups as possible while seated) while in flight. This will improve your circulation, helping promote an increased level of alertness and reduce the chance of swelling in other body regions.
- Drink plenty of fluids. Drinking lots of water and juices will help you to stay well hydrated.
- If you arrive in the morning, plan to stay awake. If possible, try to wait until the local bedtime to sleep. You will sleep better and be less likely to suffer insomnia than if you take a nap upon arriving. A daytime flight may help since nighttime flights may exacerbate jet lag.
- If you have important business that requires peak mental or physical performance, arrive at your destination several days early in order to get used to the time change. Expect nearly a day to recover for every time zone crossed. For example, six hours of time difference requires six days to recover.
Treating jet lag
A controversial treatment for jet lag is melatonin, a synthetic human hormone that promotes sleep. Several studies have shown that melatonin can alleviate jet lag. When melatonin was examined in scientific studies, eight of the 10 trials found that taking melatonin close to the target bedtime at the destination (10 p.m. to midnight) decreased jet lag from flights crossing five or more time zones. However, other studies show little or no benefit to melatonin in preventing jet lag.
Some travelers take modafinil (Provigil®) to fight jet lag. This prescription medication increases alertness in those doing night shift work but is not approved by the FDA for jet lag.
Another treatment for jet lag that has offered some success is the use of artificial lights to accelerate the adjustment of the body clock. Scientific research has shown that exposure to light at certain times during your body's circadian cycle sets your internal clock eastward and, at other times, westward. This theory involves seeking bright light at the appropriate time and avoiding sunlight at other times.
This article was reviewed and updated June 2007.
Return to the previous page
|
