Pilot Survey: Acclimatization Practices of High-Altitude Recreationalists

Acute mountain sickness (AMS) will occur if ascent to high altitude is rapid. Any type of travel to altitudes around 2,500 meters (8,000 feet) is associated with an increased risk of developing AMS. AMS symptoms include fatigue, headache, poor appetite, nausea, vomiting, weakness, tachycardia, dizziness, and sleep disturbances, and can be physically disabling to the high-altitude traveler. Prevention of AMS through acclimatization procedures such as gradual ascent and pharmacologic agents that aid in the body's accommodation to the hypobaric hypoxia resulting from high altitude exposure, are key strategies. Forty percent of South Pole Station scientists and support staff during the 2006 and 2007 summer deployments chose to defer acclimatization medications prior to rapid ascent from McMurdo Station at sea level to the high-altitude polar plateau at 2,835 meters (9,300 feet), placing them at risk for developing AMS (Anderson et al., 2011). Medical evacuation due to AMS is resource intensive and life-threatening to the individual and the rescue team. It also results in unsuccessful job performance for the individual and precludes future Antarctic deployment. The rationale and reasons for deferment of acclimatization guidelines is unknown. The objectives of the cross-sectional, descriptive research were: (a) to develop a survey tool to evaluate barriers to following high-altitude acclimatization protocols, (b) to pilot the survey tool among high-altitude recreationalists who frequently ascend rapidly to high altitude, (c) to submit recommendations for implementation of the survey tool to the U.S. Antarctic Program contractor, and (d) to disseminate the survey data to a professional audience where evidence-based knowledge can be applied. Upon obtaining Institutional Review Board (IRB) approval, high-altitude recreationalists were engaged in a survey that was conducted at 9,300 feet, an altitude approximating that of South Pole Station. The intent was to gather information regarding their rationale and reasoning for compliance with high-altitude acclimatization recommendations prior to their backcountry journey. The Wilderness Medical Society (WMS) recommendations for high-altitude acclimatization (Luks et al., 2010) stress gradual ascent and pharmacologic prophylaxis. In the study, 61% of the subjects took less than 24 hours to ascend to 9,300 feet to begin their journey and the majority (55%) of subjects (n=66) did not perceive the need for medications. Three subjects (2.5%) were taking acetazolamide and 4% consulted a health professional prior to their high-altitude trip. Forty percent (40%) of the respondents camped at the trailhead or above 6,800 feet the night before their departure and seven individuals (6%) took hikes to enhance acclimatization before their departure. Many subjects were veteran backpackers and reported symptoms could be controlled with hydration (12%), adequate rest and anti-inflammatories (40%) to control headaches, joint pain and AMS symptoms. Twelve subjects (10%) were unaware that acclimatization was recommended for ascent to high altitude. The general consensus was to "suffer through" any symptoms. Education and the dissemination of accurate information regarding acclimatization guidelines remain the key strategy in preventing AMS. Implementing the evidence-based acclimatization guidelines as a primary prevention strategy of AMS will minimize the probability of negative outcomes for all high-altitude travelers