Prevent altitude sickness

Altitude affects what your body needs and how it responds, especially when it comes to exercise. Acute mountain sickness (AMS)—caused by dry air, a decrease in oxygen, and low barometric pressure—can severely impact your health and performance. The good news is there are things you can do to help reduce your risk of altitude sickness.

Performing physical activity—whether you’re at the gym or on a mission—at moderate (4,000–7,900 ft or 1,200–2,400 m) and high (7,900–13,000 ft or 2,400–4,000 m) altitudes can be challenging. At high altitude, oxygen pressure is significantly lower, which results in less oxygen in the blood and muscle tissues. And as altitude increases, there’s also a decrease in air temperature (about 2°F for every 500 ft or 150 m), less moisture (resulting in drier air), and increased solar radiation. AMS can affect anyone who is unacclimatized and ascends too rapidly to high altitudes. Symptoms can include headache, nausea, fatigue, dizziness, vomiting, sleep problems, shortness of breath, dehydration, and impaired cognition and balance.

The risk and severity of altitude sickness are greater above 4,000 meters, and treatment might require evacuation to lower altitude or immediate medical attention. To reduce your risk of AMS, wear sunscreen, drink water, and try to limit your physical activity at altitude for the first 24 hours. Acclimate to moderate elevations (2,000–3,000 m), if possible.

With current and future military operations in mountainous regions, the issue of AMS is a serious concern. However, leaders can help manage and perhaps prevent AMS among Warfighters by being aware of the elevation, types of activities, and lengths of stay at altitudes. Visit HPRC’s Environmental Extremes section to learn more about performance at altitude.

Resources

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Clarke, C. (2006). Acute mountain sickness: Medical problems associated with acute and subacute exposure to hypobaric hypoxia. Postgraduate Medical Journal, 82(973), 748–753. doi:10.1136/pgmj.2006.047662.

Fiore, D. C., Hall, S., & Shoja, P. (2010). Altitude illness: Risk factors, prevention, presentation, and treatment. American Family Physician, 82(9), 1103–1110.

Luks, A. M., Johnson, R. J., & Swenson, E. R. (2008). Chronic kidney disease at high altitude. Journal of the American Society of Nephrology, 19(12), 2262-2271. doi:10.1681/Asn.2007111199

Luks, A. M., & Swenson, E. R. (2008). Medication and dosage considerations in the prophylaxis and treatment of high-altitude illness. Chest, 133(3), 744–755. doi:10.1378/chest.07-1417.