Meeting Fluid Needs

Consuming sufficient fluids in cold and high-altitude environments presents unique challenges, all of which must be overcome to ensure an adequate hydration state. These factors include providing adequate availability of drinking fluids, avoiding the freezing of drinking fluids, and overcoming voluntary dehydration.

Providing Adequate Availability of Drinking Fluids Fluids are heavy and not easy to transport in the best of circumstances. In cold weather and treacherous high-altitude terrains, fluid availability becomes an even greater issue. The basic strategy is for each person to ensure an availability of a minimum of 2 liters of fluids and preferably 4 liters of fluids per day. The 2 liters is truly a minimum because hard physical work in a cold, high-altitude environment may result in 2 liters of water loss per hour. The base-camp strategy of moving large amounts of food, water, and other living essentials to the highest possible altitude with the use of helicopters, automobiles, or animal packs is a logical strategy. Climbing to a higher altitude could then proceed from the base camp, with climbers carrying sufficient food and fluid for the amount of time away from the base camp. Using melted snow or ice as the source of fluids is not a reasonable planning option; melting snow and ice at high altitude takes a great deal of time and adds significant weight in fuel, pots, and stoves. In addition, it is possible that the available ice and snow is impure and not fit for consumption. It has been reported that Giardia lamblia, a diarrhea- causing intestinal parasite, is present in high-altitude regions.²⁹ Of course, in emergency situations any available fluids should be consumed, but the risk of infection is present if purification devices are not used.

Avoiding the Freezing of Drinking Fluids Climbers should carry drinking fluids close to the body to keep them from freezing and should even consider keeping fluids with them inside their sleeping bags while sleeping. The alternative (frozen fluid) is simply too difficult to deal with.³³ A unique strategy for keeping fluids from freezing is to add glycerol, which may improve fluid retention, adds calories to fluids, and reduces the freezing point. The last characteristic of glycerol is rarely considered, but for the athlete working in a cold environment, it is extremely important. The added calories are also an important benefit of glycerol because both cold-weather and high-altitude work commonly induce a hypocaloric state.

Overcoming Voluntary Dehydration When left to their own devices, athletes typically consume less fluid while exercising than is needed to sustain an optimal hydration state. This condition, termed voluntary dehydration, may be an even greater problem when athletes exercise in the cold than when they exercise in the heat. The basis for this remains unclear, but two theories, one physiological and one practical, have been suggested as the possible cause:³⁴ There is a possibility that cold skin or lower core body temperature modifies the thirst sensation and (2) the voluntary restriction of fluids seems to occur most often late in the day, an act that blunts the necessity for an athlete to leave a warm tent to urinate in a cold and unfriendly environment during the night. The only reasonable solution to avoid voluntary dehydration is for athletes to place themselves on a fixed drinking schedule, whether or not the sensation of thirst exists.³⁵ Having small sips of fluids at regular intervals also eliminates the need to consume a large volume of fluid at one time, which may stimulate the need to urinate.