Cabin pressure causes gases inside the body to expand. Increased gases remove oxygen from the blood and can cause health problems in chronically ill people.
Long periods of immobility can cause blood clotting in the legs. Blood clots pose serious risks since they may travel to the lungs and cause pulmonary embolism (arterial blockage).
Expectant mothers are allowed to fly as long as they are not in the late stages of their pregnancy. Pregnant women should consult with physicians before flying.
Travelers who have serious chronic illnesses such as anemia and diabetes, are taking medication, or have recently had surgery should consult their physician before flying. Variations in air pressure, humidity and oxygen concentration can aggravate underlying conditions.
Air travel facilitates the passage of communicable illnesses and allows diseases to spread easily from country to country. Acutely ill persons should not travel by air.
Flying across many time zones disrupts the body's timing. Jet lag may affect bowel functioning, disrupt sleep patterns, and reduce mental and physical performance.
