Airplane Travel and Blood Oxygen Saturation Typically, in-cabin air pressure is equivalent to that seen at 5000 to 8000 ft. Local hypoxia causes vasodilation (decrease in blood pressure) and increased capillary permeability, as well as increased ventilatory effort and heart rate.

Contrary to popular belief, systemic blood pressure often increases slightly rather than drops during long airplane flights. This is due to several environmental stressors: the lower cabin pressure results in lower oxygen saturation in the blood, which causes the heart to beat faster and the pulmonary arteries to constrict, raising pressure in the lungs. Furthermore, factors like dehydration, cabin noise, and the physical stress of sitting in a cramped position for hours can trigger a "stress response" in the body, releasing cortisol and adrenaline which naturally elevate blood pressure. However, some passengers may experience a drop in blood pressure—known as orthostatic hypotension—when they suddenly stand up after hours of sitting, which can lead to dizziness or fainting (syncope). This is usually caused by blood pooling in the legs. To mitigate these effects in 2026, medical experts suggest wearing compression socks to aid circulation, staying hydrated to maintain blood volume, and performing "seat exercises" like ankle pumps every hour to keep the heart and vascular system functioning smoothly.