Jetting across time zones can take a toll on your body's internal clock. Here's how to cope with fatigue and other symptoms while traveling.
Jet lag, also called jet lag disorder, is a temporary sleep problem that can affect anyone who quickly travels across multiple time zones.
Your body has its own internal clock (circadian rhythms) that signals your body when to stay awake and when to sleep. Jet lag occurs because your body's clock is still synced to your original time zone, instead of to the time zone where you've traveled. The more time zones crossed, the more likely you are to experience jet lag.
Jet lag can cause daytime fatigue, an unwell feeling, difficulty staying alert and gastrointestinal problems. Jet lag is temporary, but it can significantly reduce your vacation or business travel comfort. Fortunately, there are steps you can take to help prevent or minimize jet lag.
Symptoms of jet lag can vary. You may experience only one symptom or you may have many. Jet lag symptoms may include:
Jet lag symptoms usually occur within a day or two of travel if you've traveled across at least two time zones. Symptoms are likely to be worse or last longer the more time zones that you've crossed, especially if you travel in an easterly direction. It usually takes about a day to recover for each time zone crossed.
Jet lag is temporary. But if you're a frequent traveler and continually struggle with jet lag, you may benefit from seeing a sleep specialist.
Jet lag can occur anytime you cross two or more time zones. Jet lag occurs because crossing multiple time zones puts your internal clock (circadian rhythms), which regulates your sleep-wake cycle, out of sync with the time in your new locale.
For example, if you leave New York on a flight at 4 p.m. on Tuesday and arrive in Paris at 7 a.m. Wednesday, your internal clock still thinks it's 1 a.m. That means you're ready for bed just as Parisians are waking up.
And because it takes a few days for your body to adjust, your sleep-wake cycle, along with most other body functions, such as hunger and bowel habits, remains out of step with the rest of Paris.
A key influence on your internal clock is sunlight. That's because light influences the regulation of melatonin, a hormone that helps synchronize cells throughout the body.
Certain cells in the tissue at the back of your eye (retina) transmit the light signals to an area of your brain called the hypothalamus.
At night, when the light signal is low, the hypothalamus tells the pineal gland, a small organ situated in the brain, to release melatonin. During daylight hours, the opposite occurs, and the pineal gland releases very little melatonin.
You may be able to ease your adjustment to your new time zone by exposing yourself to daylight in the new time zone so long as the timing of light is done properly.
Some research shows that changes in cabin pressure and high altitudes associated with air travel may contribute to some symptoms of jet lag, regardless of travel across time zones.
In addition, humidity levels are low in planes. If you don't drink enough water during your flight, you can get slightly dehydrated. Dehydration may also contribute to some symptoms of jet lag.
Factors that increase the likelihood you'll experience jet lag include:
Motor vehicle accidents caused by drowsy driving may be more likely in people who are jet-lagged.
A few basic steps may help prevent jet lag or reduce its effects:
Regulate bright light exposure. Because light exposure is one of the prime influences on your body's circadian rhythm, regulating light exposure may help you adjust to your new location.
In general, exposure to light in the evening helps you adjust to a later than usual time zone (traveling westward), while exposure to morning light can help you adapt to an earlier time zone faster (traveling eastward).
The one exception is if you have traveled more than eight time zones from your original time zone, because your body might mistake early morning light for evening dusk. Your body might also mistake evening light for early morning light.
So, if you've traveled more than eight time zones to the east, wear sunglasses and avoid bright light in the morning, and then allow as much sunlight as possible in the late afternoon for the first few days in your new location.
If you have traveled west by more than eight time zones, avoid sunlight a few hours before dark for the first few days to adjust to the local time.
Jet lag is generally temporary and usually doesn't need treatment. Symptoms often improve within a few days, though they sometimes last longer.
However, if you're a frequent traveler continually bothered by jet lag, your doctor may prescribe light therapy or medications.
Your body's internal clock is influenced by exposure to sunlight, among other factors. When you travel across time zones, your body must adjust to a new daylight schedule and reset, allowing you to fall asleep and be awake at the appropriate times.
Your doctor may recommend light therapy. This involves exposure to an artificial bright light or lamp that simulates sunlight for a specific and regular amount of time when you're meant to be awake. Light therapy comes in a variety of forms, including a light box that sits on a table, a desk lamp or a light visor that you wear on your head.
Light therapy may be useful, for example, if you're a business traveler and are often away from natural sunlight during the day in a new time zone.
These medications — sometimes called sleeping pills — may help you sleep during your flight and for several nights afterward. Side effects are uncommon, but may include nausea, vomiting, amnesia, sleepwalking, confusion and morning sleepiness.
Although these medications appear to help sleep duration and quality, they may not lessen daytime symptoms of jet lag. These medications are usually only recommended for people who haven't been helped by other treatments.
Use sunlight to reset your internal clock. It's the most powerful natural tool for regulating the sleep-wake cycle.
Morning light exposure can usually help you adjust to an earlier time zone (traveling eastward), while evening light helps you adapt to a later time zone (traveling westward). Plan ahead to determine the best times for light exposure based on your departure and destination points and overall sleep habits:
Combining light exposure with exercise such as walking or jogging may help you adapt to the new time even faster.
Beverages with caffeine such as coffee, espresso and soft drinks may help offset daytime sleepiness. Choose caffeinated drinks wisely. Avoid caffeinated beverages after midday since caffeine consumed after that time may make it even more difficult to fall asleep or sleep well.
As a jet lag remedy and sleep aid, melatonin has been widely studied, and it's now a commonly accepted part of effective jet lag treatment. The latest research seems to show that melatonin aids sleep during times when you wouldn't normally be resting, making it beneficial for people with jet lag.
Your body treats melatonin as a darkness signal, so melatonin generally has the opposite effect of bright light.
The time at which you take melatonin is important. If you're trying to reset your body clock to an earlier time, such as after flying east, you should take melatonin at local bedtime nightly until you have become adapted to local time. If you're trying to reset your body clock to a later time, such as after flying west, melatonin should be taken in the morning.
Doses as small as 0.5 milligram seem just as effective as doses of 5 milligrams or higher, although higher doses have been shown by some studies to be more sleep promoting. If you use melatonin, take it 30 minutes before you plan to sleep or ask your doctor about the proper timing.
Avoid alcohol when taking melatonin. Side effects are uncommon but may include dizziness, headaches, daytime sleepiness, loss of appetite, and possibly nausea and disorientation.
Some people use exercise to try to ease the effects of jet lag.
If you want to try an alternative therapy, such as an herbal supplement, be sure to check with your doctor first because some therapies may interact with other medications or cause side effects.
May 5th, 2021
