The length of international flights often means a lack of exercise and movement and this causes swelling of the legs as blood pools in them. There is then the possibility of deep vein thrombosis or DVT if blood clots form in the leg. However, the World Health Organization explains in their publication "International Travel and Health" that this risk is minimal unless other health risks are present.
Passengers can minimize this threat if they follow a few simple exercise suggestions like flexing their legs, rotating their ankles, or even squatting and standing while waiting in line for the restroom.
The World Health Organization asserts in "International Travel and Health" that the low humidity on international flights does not cause dehydration. In theory, this is true, but other factors contribute to passenger dehydration on international flights. Drinking alcohol will dehydrate passengers and some might arrive at the airport dehydrated.
The experts at Travel Smart suggest that passengers drink a bottle of water after passing through the security checkpoint and then fill it before boarding the plane. The World Health Organization (WHO) suggests using moisturizer, eye drops and nose spray for uncomfortable dryness.
Jet lag is a common effect of international flights as the traveler frequently reaches a destination with one time while his body and mind are still set on another time. International flights get passengers to their destination much more quickly than other forms of travel, but as The Travel Doctor explains the passengers' internal clocks do not have time to adjust.
WHO in its publication "International Travel and Health" suggests steps that include travelers arriving well rested and avoiding alcohol during the flight. Travel Smart suggests eyemasks and ear plugs to facilitate sleep and to drown out engine and other noises on the plane.
International flights often have psychological effects on travelers. WHO explains that stress and fear of flying can occur at anytime before or during the flight. The long journey, the less than perfect conditions, the cramped, enclosed space and other changes create and exacerbate levels of fear and stress.
Air rage is a recently recognized effect of flying and, as defined by The Travel Doctor, describes the psychological and/or physical violence of some individuals during flights. The effect of the flight on passenger stress, rather than fear of the flight, is a contributing factor in air rage. The effects caused due to a disruption of travelers' normal routines like smoking and other things might feed into this rage.
WHO explains that the ever-increasing quality of air filters on planes eliminates the effect of breathing poor quality uncirculated air. However, international flights do have an effect on health if the passenger is sitting close to or comes in contact with someone who has a communicable illness. These illnesses may be spread through direct or indirect contact. When these germs are coupled with the body's lowered resistance due to the effects of the flight on sleep and stress, illness is likely to occur.
