Several conditions are common even among healthy people while in transit. For motion sickness, see Motion Sickness.
Blood clots can occur when people sit for long periods during air, rail, bus, or car travel. Blood clots (deep vein thrombosis—see see Deep Vein Thrombosis (DVT)) are more common among people who
Blood clots form in leg or pelvic veins and occasionally dislodge and travel to the lungs (called pulmonary emboli—see see Pulmonary Embolism). Some blood clots in the legs do not cause symptoms, whereas others cause cramping, swelling, and color changes of the calves and feet. Pulmonary emboli are much more serious than blood clots in the legs. People may first develop a sensation of not feeling well, followed by shortness of breath, chest pain, or fainting. Pulmonary emboli are sometimes fatal.
The risk of developing blood clots can be reduced by changing positions frequently, straightening and moving the legs frequently while seated, drinking enough fluids, and getting up to walk and stretch every 1 to 2 hours. Prolonged leg crossing may decrease leg circulation and should be avoided. Avoiding caffeine and alcohol and wearing elastic support stockings also reduce risk.
Ear and Sinus Pressure
Ear and sinus pressure while flying is the result of changes in air pressure in the airplane (cabin pressure). Normally, as an airplane takes off and climbs (ascends), cabin pressure decreases, and small pockets of air trapped in the sinuses and middle ear expand, leading to ear pressure, ear popping, or both and to mild sinus pressure or discomfort. As an airplane descends, cabin pressure increases, and similar symptoms occur. These mild sensations usually disappear as air pressure in the sinuses and ears equalizes with cabin pressure.
Untreated dental problems or teeth that were subjected to recent dental procedures may become painful when air pressure changes. In people with allergies, sinus problems, and head colds, the passages that connect the ears and sinuses to the nose and mouth become inflamed and sometimes blocked by mucus, which prevents air pressure from equalizing normally. People with these problems may experience significant discomfort. Swallowing (particularly while holding the nose closed) frequently or yawning during descent, taking decongestants before descending, or blowing hard against a closed mouth and pinched nostrils helps equalize air pressure. Some people suck on hard candies during descent. These actions are normally sufficient to relieve minor ear and sinus discomfort.
Children are particularly susceptible to the pain of unequal air pressure. They should chew gum, suck hard candy, or be given something to drink during ascent and descent to encourage swallowing. Babies can be breastfed or given a bottle or pacifier.
Sleep disturbance after air travel (jet lag) is common when people rapidly travel across more than 3 time zones. Sleep disturbance does not occur with sea, rail, or car travel because travelers have time to adjust to time zone changes. The most obvious symptom is fatigue on arrival. Other symptoms include irritability, difficulty sleeping (insomnia), headache, and difficulty concentrating. Jet lag can be minimized by starting to adjust sleep and wake times 1 or 2 days before departure to coincide with those of the destination time zone. In flight, a person should avoid smoking, caffeine, and excessive alcohol. Managing exposure to light can also help travelers adjust to a new time zone.
People traveling westward tend to awaken earlier and feel tired earlier than they should by local time. For example, if people who normally wake up at 7 am and go to bed at 11 pm travel 3 time zones west, they tend to awaken at 4 am local time and feel the need for sleep by 8 pm. To adjust, people should try to get bright sunlight in the late afternoon and try to stay up until the appropriate bedtime.
People traveling eastward tend to awaken later and stay awake longer than they should by local time. For example, if people who normally wake up at 7 am and go to bed at 11 pm travel 3 time zones east, they tend to awaken at 10 am local time and not feel the need for sleep until 2 am. To adjust, people should get bright sunlight in the early morning. Those who had an overnight flight should try to remain physically active until evening and try not to nap.
Short-acting sedatives may help people fall asleep at the appropriate local time after eastward travel. However, sedatives may have side effects, such as daytime drowsiness, amnesia, and nighttime insomnia. Long-acting sedatives, such as diazepam, can cause confusion and falls in older people and should be avoided.
The hormone melatonin regulates the sleep-wake cycle. Some doctors have recommended using melatonin supplements after eastward travel to reset the body's internal clock for sleep. Although some travelers report melatonin is beneficial, its effectiveness and safety have not been thoroughly proved.
Dehydration while flying is common because of the low humidity in airplanes. Dehydration tends to affect older people and people who have certain medical conditions, such as diabetes, or who take drugs used to increase sodium and water excretion in the urine (diuretics). The main symptoms are light-headedness, drowsiness, confusion, often thirst and dry mouth, and, occasionally, fainting.
Dehydration can be prevented by drinking fluids and by avoiding alcohol and caffeine. Dry skin can be treated with moisturizers.
Spread of Infection
Spread of infection on airplanes and cruise ships often receives media attention but is relatively uncommon. Concern is greatest for influenza, viral diarrhea, and bacterial meningitis. Travelers can minimize their risk of influenza by making sure they have received the most current influenza vaccine. They can minimize their risk of diarrhea and some other infections by washing their hands frequently and using alcohol-based hand sanitizers. Some cruise ships offer antibiotics to passengers who have been in close contact with passengers who have these infections.
Minor injuries are common during travel. Unaccustomed lifting of heavy luggage is a common cause of shoulder injuries. Luggage falling out of overhead storage bins can cause other significant injuries. Airplane turbulence may cause motion sickness or injury. While seated, passengers should keep their seat belts fastened at all times. During ship travel, injuries can be prevented by wearing shoes that provide good traction on wet surfaces, using handrails and removing sunglasses before entering ship stairwells, and remaining alert in unfamiliar surroundings. A flashlight is useful for preventing falls at night.
Anxiety affects many people who travel. Fear of flying, fear of confined spaces, and worries about medical conditions worsening during flight are common sources of anxiety. Anxiety can cause insomnia, making jet lag worse. People may hyperventilate, often with symptoms such as chest pain, trouble breathing, muscle spasms, and tingling in the arms and hands and around the mouth. The company of a seasoned traveler or caregiver may help relieve anxiety. Cognitive therapy and desensitization programs or hypnosis may also help. Sedatives or antianxiety drugs, such as zolpidem or alprazolam, taken before and sometimes during the trip, may be of benefit (see see Drugs Used to Treat Anxiety Disorders).
Last full review/revision February 2013 by Christopher Sanford, MD, MPH, DTM&H