What is a primary preventive measure for High Altitude Pulmonary Edema (HAPE)?

Gradual ascent above 2,500 meters is a primary preventive measure for High Altitude Pulmonary Edema (HAPE) because it allows the body to acclimatize to decreased oxygen levels effectively. Altitude sickness, including HAPE, is more likely to occur when individuals ascend too quickly, as the body does not have adequate time to adjust to the changes in atmospheric pressure and oxygen availability.

Acclimatization involves physiological adjustments such as increased respiratory rate, enhanced oxygen transport, and improved blood flow, all of which can help mitigate the risk of developing altitude-related illnesses. By ascending gradually, individuals give their bodies the opportunity to adapt, which significantly reduces the likelihood of experiencing HAPE.

This method of prevention stands in contrast to the other options; for instance, rapid ascent can lead to a higher risk of HAPE as it does not allow for necessary acclimatization. The use of steroids, while sometimes indicated in the treatment of severe altitude illnesses, is not a preventive measure for HAPE. Additionally, while immediate descent to sea level can be an effective treatment for HAPE, it does not aid in the prevention of the condition itself.