Recently, while attending a conference in Breckenridge, Colorado, participants were encouraged to practice several preventive strategies to avoid experiencing high altitude illness (HAI), also known as acute mountain sickness (Taylor, 2011). As the elevation of Breckenridge is about 10,000 ft, and problems can arise at 5,000 ft (about the elevation of Denver), there was a very real possibility of HAI. The two strategies that were nutrition related are discussed here.
What is high altitude sickness? A person with HAI usually presents with complaints of headache "and at least one of following symptoms: fatigue or weakness; dizziness or lightheadedness; gastrointestinal symptoms (nausea or vomiting, anorexia); difficulty sleeping" (Fiore, Hall, & Shoja, 2010, p. 1104). Left untreated, symptoms may progress to more serious conditions such as high-altitude cerebral edema or high-altitude pulmonary edema (Taylor, 2011). About 25% to 38% of those who travel to high altitudes experience HAI (Fiore et al.).
Although symptoms may appear at an elevation of 5,000 ft, more often they appear with rapid ascent to elevations of >=8,200 ft (Fiore et al., 2010). Symptoms can vary depending on the altitude at which individuals begin and end their ascent and typically appear between 6 and 12 hours after reaching a high altitude. Thus, travelers to high altitude destinations such as Colorado, and other Rocky Mountain States or provinces, are at risk. Although skiers and mountain climbers are particularly susceptible to HAI, increased interest in global travel and exploration can expose the nonconditioned traveler to HAI. For example, it is not unusual for tour groups to visit Mont Blanc, which is 15,781 ft high (3 miles high) or Mount Kilimanjaro, which is 19, 341 ft high (almost 4 miles high).
Why does it happen? Zafren (2014) says it best. "Altitude illness is caused by decreased oxygen availability due to low atmospheric pressure (hypobaric hypoxia)" (p. 29). Consequently, as a person ascends to higher altitudes, barometric pressure falls. When barometric pressure falls, so too does the partial pressure of oxygen (Imray, Wright, Subudhi, & Roach, 2010). The outcome is hypobaric hypoxia. Symptoms are the result of the body trying to acclimate to these changes.
How is it treated? Treatment is focused on helping an individual acclimate to changing atmospheric pressures caused by being in higher elevations. Although the best approach to avoid HAI is to ascend to a higher elevation slowly (Fiore et al., 2010; Zafren, 2014), many find this very hard to do. Building in time for acclimatization through planned stays at an intermediate level can help. Pharmacologically, the drug of choice is acetazolamide, which is a carbonic anhydrase inhibitor (Taylor, 2011; Zafren, 2014). Other drugs that may be used are dexamethasone, acetaminophen, and nonsteroidal anti-inflammatory drugs. The latter are used to treat headache associated with HAI.
Nonpharmacological approaches include maintaining adequate, but not excessive, hydration (Zafren, 2014) and ingestion of carbohydrates. Adequate hydration is important as diuresis can occur. Increasing carbohydrates is thought to "improve arterial oxygenation during the acute hypoxic exposure" (Imray et al., 2010, p. 1453). Increased respiratory effort requires additional energy.
What can nurses do? Reviewing why HAI occurs with persons who anticipate travelling to higher altitude sites is a first step in helping with prevention. Once their understanding has been established, reinforce positive dietary practices. Maintaining adequate hydration, while avoiding over hydration is very important. Encourage them to eat complex carbohydrates such as fruit and whole grains. This information can be used to assist in taking proactive preventive measures. More information is available on the following Web sites:
Centers for Disease Control and Prevention: http://wwwnc.cdc.gov/travel/yellowbook/2016/the-pre-travel-consultation/altitude
Cleveland Clinic: https://my.clevelandclinic.org/health/diseases_conditions/hic-altitude-sickness
WebMD: http://www.webmd.com/a-to-z-guides/altitude-sickness-topic-overview
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