DISORDERS CAUSED BY ALTITUDE - Medicine for Mountaineering and Other Wilderness Activities - page 356

Impairment of food absorption in the gastrointestinal tract has been suggested but not
confirmed as a cause for the weight loss, which reportedly cannot be prevented by forced
feeding. The tastelessness of the freeze-dried foods carried by most expeditions may be
more significant. Climbers often go hungry at high altitude rather than eat food that they
do not crave.
Menus should consist largely of foods that all party members enjoy, but foods should
also be carried to satisfy individual tastes. Diets should contain large amounts of sweets,
which are usually consumed in large quantities at high altitudes. Fatty foods or highly con-
densed rations may not be well tolerated. During days of heavy exertion, many climbers
findthatfrequentsmallhigh-carbohydratesnacksarebetterthanlessfrequentlargermeals.
On prolonged expeditions when fresh vegetables and fruits are not available, possible
vitamin C deficiency can be prevented with ascorbic acid. However, most packaged drinks
suchaslemonadeororangejuicecontainsomevitaminC.Furthermore,severalmonthsare
required for signs of vitamin deficiency to appear in individuals previously in good nutri-
tional condition.
If vitamin intake appears inadequate, one or two multivitamin tablets per day can be
taken.AhighervitaminintakeorspecialvitaminssuchasEorBcomplexareofnobenefit
at high altitudes and may be harmful. Vitamin requirements are only minimally increased
by the rigors of an expedition, and a standard diet contains much more vitamins than are
needed.Anyexcessissimplyexcretedintheurine.ExcessvitaminAandD—possiblyoth-
ers—are definitely harmful.
High-Altitude Deterioration
Acclimatized people can live a normal life span at elevations as high as 17,500 feet
(5300 m) and can live and work for several weeks up to 20,000 feet (6100 m). At higher
elevations deterioration rather than further acclimatization occurs.
Spending as little time as possible at extreme altitudes and periodically descending for
recovery at lower altitudes for several days can minimize high-altitude deterioration. Ad-
equate fluid intake is essential. The urine volume must be greater than 500 ml every day,
preferably two to three times greater, and urine color should be clear or light yellow, not
deepyellowororange.Effortsmustbemadetoeatanadequateamountoffoodinspiteofa
poor appetite. An adequate caloric intake is needed more than specific nutrients. Nutrition-
al deficiencies do not develop in healthy individuals during the short periods expeditions
are at high altitudes.
Oxygen during sleep—two liters per minute through a face mask—is beneficial. No
drugs are known to minimize deterioration, but sleeping with low-flow oxygen does make
a difference.