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Avoiding Altitude Illness
Air travel quickly take us from a near sea level home to high altitude destinations: Denver, Mexico City, Katmandu. Rent a car at the airport, drive higher into the mountains and within hours it is possible to be exposed to potentially life threatening altitude illnesses. The danger is increased by drinking caffeinated coffee, performing excessive exercise and contracting respiratory illnesses caused from acute infections and allergies. Alpine skiers, snow boarders, mountaineers, and day hikers who are not completely acclimatized are at risk. What follows is an outline of altitude illnesses and potentially life saving survival procedures.
Most altitude sickness occurs above 8000 feet. A person with respiratory illness may have problems below this altitude.
Particularly Problematic: Asthma, bronchitis, smokers, emphysema, heart disease, sickle cell disorders (black climbers be aware), thalassemia, drugs, sedatives, anything that compromises respiratory efficiency.
Ascents above 14,000 feet require acclimatization.
Ascents above 18,000 feet for extended stays may induce physical and mental deterioration. At 18,000 feet you have1/2 the oxygen available at sea level.
Problems include: muscle wasting, lack of sleep, lost endurance and fitness, tachycardia, compromised respiration leading to altitudes illnesses. Retinal blood flow is increased. Decreased cardiac efficiency.
There is both less oxygen and less partial pressure of oxygen at high and extreme altitudes, blood plasma volume decreases, and as a result of hyperventilation alkalosis occurs. According to Holtgren, it requires 10-14 days to return blood pH to normal. Diuresis may rectify this problem, but may lead to dehydration
TIP: hydrate often at altitude. Avoid diuretics such as coffee and teas at high altitudes.
Sleep and Breathing Problems
The reduced partial pressure of oxygen at high altitude decreases further with exercise and sleep. More rest is required. Even when walking rest steps must be used. A rest step is the process of taking a step and resting two beats or more before taking the next step.
Sleep under normal conditions decreases ventilatory drive, the physical process of inhaling and exhaling. Less ventilatory drive requires an greater use of energy to breathe. At altitude this physiology is exacerbated. Above 10,000 feet ventilation increases. And the work of breathing at 27,000 feet leaves little energy for anything else. High altitude also causes a decreased affinity in hemoglobin for oxygen in the lungs. This compounds the breathing problem.
Avoiding Altitude Illnesses
Acclimatization: Avoid flying to altitudes above 8000 feet. Walk up. Acclimatization requires two to four days at altitude of 5000 feet for climbs from 8000 to 14,000 feet.
For 14,000 to 22,000 feet spend two to four more days at 10,000 to 12000 feet. Your first day at higher altitude should require little effort and be a rest day. Above 14,000 feet all are vulnerable. Climb at a rate of 1000 feet per day or less. Take a rest day every third day or better every other day.
When returning to low altitude all climbing acclimatization is lost within two weeks.
Drug Therapy: Acetazolamide, Diamox may be used in conjunction with acclimatization to minimize altitude sickness in in those predisposed to it. But it is no substitute for acclimatization and is typically used during rapid ascent in rescue scenarios. According to Jim Duke, former Chief of Germ Plasm at the USDA, drinking thymol from thyme tea may provide some protection from altitude illness. This hypothesis is based on to studies performed by the Air Force and Navy. Research is preliminary.
Climb high, sleep low! Sleep is your enemy at high altitude.
High Mountain Illnesses can be avoided by gradual acclimatization to higher altitudes.
A high carbohydrate (70 percent) diet two days before your descent may be helpful. Drink plenty of water before and during climbing. Avoid camp sites that are over 1000 feet higher than the previous days camp site. Exercise and improve your overall fitness before going to the mountains.
What are the High Altitude Illnesses
HAPE High Altitude Pulmonary Edema caused by rapid ascent to above 8000 feet. May occur in recreational hikers and skiers who sleep at altitudes at or above 8000 feet, especially if heavy physical exertion is part of the mix. This illness is a result of poor acclimatization and occurs in younger people more often, incidence is less than .4% in persons over 21 and as high as 6% in those younger (Forgey, Wilderness Medicine 4th Edition, GLOBE PEQUOT PRESS, Pp. 196-197).
Symptoms: shortness of breath, cough, rapid heart rate, weakness, headache progressing to bloody sputum, fever, chest congestion, chest pain. Symptoms may get worse, progress at night. Respiratory rates over 20 per minute is a medical emergency and requires immediate evacuation to lower altitude and medical intervention to prevent coma and death.
HACE High Altitude Cerebral Edema rarer, but more dangerous that HAPE, this altitude illness may occur as low as 8000 feet, but is more common above 11,500 feet.
Symptoms: severe headache, confusion, aberrant emotional behavior, unstable gait, poor dexterity, loss of vision, muscle paralysis in face. Requires immediate descent. Re- pressurization in a Gamow Bag if available. May cause death after restless sleep, coma.
AMS Acute Mountain Sickness may be common if the person is not acclimatized. Rare at altitudes from 5000 to 6500 feet, is fairly common to the unfit above 10,000 feet.
Symptoms: May overlap symptoms of other altitude illnesses such as: headache, nausea, shortness of breath, weakness, poor or disturbed sleep. Symptoms may lead to irregular or periodic breathing called Cheyne-Stokes breathing, but this is not always the case. Prevention and treatment is gradual descent to lower altitudes. Diamox (acetazolamide) may be taken prophylactically 12 hours before the ascent and for up to 5 days there after.
Wrap up: There are other altitude illnesses beyond the scope of this paper. Any unusual medical problems or symptoms such as retinal blood vessel hemorrhages, swelling of the face, arms, legs...also flatulence, dehydration, hypothermia require attention, if symptoms persist return to a lower altitude to prevent more serious altitude illnesses.