Being in strong light stops melatonin secretion, but darkness triggers melatonin secretion, which may be imbalanced by crossing time zones or conditions inside the plane cabin. Melatonin, when secreted, induces a heavy desire to sleep. It is caused by a disruption of the circadian rhythm, which is maintained and controlled by melatonin from the pineal gland. Generally, the effects of jet lag will wear off within a week. The incidence of jet lag increases with the number of time zones crossed. Passengers who travel regularly are likely to change time zones and can experience circadian rhythm misalignment, leading to jet lag disorder (JLD). Some respiratory physicians would even suggest oxygen supplementation for patients with blood oxygen saturation of less than 94%.Īirplane travel and sleep disturbances caused by air travel are frequently reported. Generally, blood oxygen saturation beneath 90% is not sustainable in the long term. This study concluded that this hypoxia in conjunction with the dehydration, immobility and low humidity associated with airplane travel could contribute to morbidity during and after airplane travel. One study found a passenger had a blood oxygen saturation of 94% at ground level and 85% at altitude. Local hypoxia causes vasodilation (decrease in blood pressure) and increased capillary permeability, as well as increased ventilatory effort and heart rate. Typically, in-cabin air pressure is equivalent to that seen at 5000 to 8000 ft.

Travelling to high altitudes such as mountains or ski resorts pose a high risk of hypoxemia (oxygen deprivation) due to the decrease in oxygen pressure compared to sea-level. Image Credit: Volkova Natalia / Shutterstock Airplane Travel and Blood Oxygen Saturation

The Travelers Within by Daniel Mode