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While travel can be fun, it can expose you to obvious as well as hidden hazards, possibly causing illness or exacerbating existing health issues. Lack of sleep combined with stress, dehydration, increased exertion levels, musculoskeletal stresses and a change in medical-care delivery systems could have an impact on the traveler. A few disorders, however, are actually caused by the process of getting from one place to another around the globe. The four most common conditions caused by travel are jet lag, motion sickness, deep vein thrombosis, and high altitude illness. The following sections provide a summary of the causes and symptoms of each condition as well as tips for prevention and instructions for treatment.
Long-distance travel in which humans cross several time zones in a short time can cause what is commonly known as jet lag, also called rapid time zone change syndrome or desynchronosis. This condition results from your circadian rhythm — your internal clock, which is attuned to the day-night cycle at your departure location — being out of sync with the day-night cycle at your destination with little or no time to adjust. Jet lag primarily affects air travelers because of the greater distances and time zones covered in a relatively short time. Boaters may have some difficulty with this condition if they do not make regular accommodations as they travel across the globe.
Feeling sleepy, hungry and alert at the wrong times are common symptoms of jet lag, which may affect your social life and your ability to work, exercise or sleep. Fortunately, your internal clock will synchronize with your new environment within a few days. The more times zones you cross, the more intense your symptoms are likely to be and the longer they will take to diminish.
PREVENTION AND TREATMENT
A few days to a week before your departure, try to gradually move your bedtime to what it will be at your destination — i.e., if you are traveling east, where night comes sooner than at your departure location, go to bed one hour earlier than you usually would for as many days as the number of time zones you will travel through. To make it easier to fall asleep early, avoid coffee, tea, chocolate, alcohol and exercise for three to four hours before your new bedtime. Then wake up earlier in the morning and try to catch some sunshine to help your body’s internal rhythm adjust. If you are traveling west, you should do the reverse routine — gradually go to bed and wake up later in the days leading up to your departure.
Jet lag may be exacerbated by poor sleep during an overnight flight. Falling asleep on a plane can be difficult for several reasons. During sleep, your body temperature falls, and the activity of some hormones changes. This process usually occurs at a similar time every day, prompted by changes in surrounding light and noise. With the onset of darkness, the pineal gland in the brain starts to secrete melatonin, known as the “hormone of darkness.” Melatonin helps the body fall asleep and stay asleep, but it is not strong enough to do so on its own. To sleep well during a flight, it is important to avoid excessive consumption of caffeine and alcohol. Caffeine may prevent you from falling asleep, and alcohol will prevent you from staying asleep and experiencing normal restorative stages of sleep. The use of earplugs and an eye mask to reduce noise and mimic darkness may also help.
MOTION SICKNESS (KINETOSIS)
Kinetosis — commonly known as motion sickness — is any disorder caused by motion, such as seasickness, airsickness or carsickness, as defined by Taber’s Cyclopedic Medical Dictionary. It is a common complaint of travelers on planes or boats, in motor vehicles and even while riding animals such as horses. Most people, including experienced boaters and frequent air travelers, have experienced motion sickness at some time. All that is needed is a strong enough stimulus, which can vary widely from one person to another. Most people acclimate — or “get their sea legs” — with time, but the process can take up to two or three days.
The most distressing symptoms of motion sickness are nausea and vomiting, generally caused by an overstimulation of your inner ear’s vestibular balance organs and/or by a discrepancy between the sensory inputs from your eyes and inner ears. Other symptoms include excessive sweating, pallor (pale skin), a mild headache and malaise.
Motion sickness is not a serious medical problem, but it may lead to more significant health issues or incidents because affected individuals can develop an almost desperate inattentiveness and a reduced ability to perform simple tasks. Assume that any tasks assigned to those affected by motion sickness require supervision. Reassign critical tasks to others who are less impaired.
PREVENTION AND TREATMENT
It is best to plan ahead to reduce the risk of motion sickness. Prepare by being well rested, nourished and adequately hydrated. If you feel anxious or uneasy, avoid consuming food for two hours before you embark for a short sail, as you will likely be more comfortable with an empty stomach than with a full one. For boaters, stow and prepare your gear before the boat leaves the dock to limit the time spent below decks. While under way, position yourself on the boat where the motion is least, such as midline on the boat, low and close to the waterline or on the stern (if minimal or no exhaust is present). Avoid areas where the vertical motion is more pronounced, such as the bow or upper decks. Closing your eyes or sitting where the rocking motion of a boat is clearly visible can help prevent motion sickness. Gazing at the horizon rather than at objects in your immediate vicinity is widely accepted as helpful. Staying away from areas with strong fumes, particularly fuel or exhaust, is also a good idea. Avoid reading, looking at electronic devices or moving your head continuously back and forth because this can worsen symptoms.
Advertisements promote numerous medications, herbs, foods and devices to prevent or treat motion sickness. Although many of these aids have proved to be successful, none are known to be completely effective. Taking an over-the-counter antihistamine such as meclizine, dimenhydrinate or cyclizine before you feel sick can be helpful, but it may cause some degree of drowsiness. Antihistamines interact with many drugs, so if you have chronic health issues and are taking other medications, consult your physician before you travel so there is enough time to make any necessary adjustments.
DEEP VEIN THROMBOSIS
Deep vein thrombosis (DVT) is an acute condition in which a blood clot (also known as a thrombus) forms in one or more of the body’s deep veins, usually in the legs. These blood clots can then break free, travel through the bloodstream and cause life- threatening conditions such as a pulmonary embolism — a blood clot that lodges in the lungs. The blockage can be great enough to reduce the heart’s ability to circulate blood to the lungs, impairing vital functions such as the elimination of carbon dioxide and delivery of oxygen.
Approximately half of all DVTs are silent with no noticeable symptoms. When symptoms do occur, they may include the following:
- Swelling of the affected leg, ankle and foot
- Pain in the calf that spreads to the ankle and foot
- Warmth across the affected area
- Change in skin color to pale, red or blue
These symptoms are not exclusive to DVT, and at least half of people with similar symptoms may have conditions other than DVT.
HIGH ALTITUDE ILLNESS
Traveling to high altitudes exposes people to increasingly rarefied air and progressively decreasing amounts of oxygen, resulting in declining levels of oxygen in the blood, which can lead to impaired physical and mental performance. Responses to high altitudes vary, but most people can function normally at heights up to 8,000 feet (2,438 meters) above sea level. At altitudes greater than that, the oxygen deficit can begin to cause a condition known as acute mountain sickness (AMS). At elevations higher than 10,000 feet (3,048 meters), 75 percent of people will experience at least mild AMS symptoms.
The onset of AMS symptoms varies according to the altitude, the rate of ascent and the individual’s susceptibility to the disease. A slow ascent may allow the body to acclimate by establishing a more rapid spontaneous breathing rate to make up for the decreased oxygen in the atmosphere. Symptoms usually start 12 to 24 hours after arrival at altitude and begin to decrease in severity around the third day at a given elevation. AMS causes travelers to feel generally unwell. They may also experience a loss of appetite, headaches, lightheadedness, fatigue, breathlessness, rapid heartbeat, nausea or difficulty sleeping. Symptoms tend to be worse at night. Mild AMS does not interfere with normal activities, and symptoms generally subside within two to four days as the body acclimates. Severe HAI manifests as serious conditions known as high-altitude pulmonary edema (HAPE) or high-altitude cerebral edema (HACE), caused by the accumulation of excess fluid in the lungs or brain.
PREVENTION AND TREATMENT
Responding promptly to signs or symptoms of AMS is essential. Immediately call the nearest emergency medical services (EMS) if you or someone traveling with you experiences any of the following symptoms that could be HACE or HAPE:
- Severe breathing problems
- Altered level of alertness
- Coughing up blood
If you cannot count on EMS aid, move the affected individual to a lower altitude as quickly and as safely as possible, and administer oxygen if it is available. Keep victims warm, and be sure they stay well hydrated if they are conscious.
To avoid high altitude illness, it is important to ascend slowly enough to allow time for your body to acclimate. Some people also find it beneficial to take prophylactic medication to help with the acclimatization process or to prevent some ill effects. If you plan to travel to a high-altitude location, visit your doctor or a travel clinic before your trip to evaluate your risk of HAI and to obtain prophylactic medication that may prevent or alleviate AMS.