Hypothermia and Dehydration
When people think of hypothermia, the condition in which your body temperature is enough below normal that you can’t function normally, they usually think only of the cold. But, usually dehydration plays a major role in hypothermia, if your blood volume is up to normal, your body can circulate enough fluid to your muscles and viscera to keep you functioning. As the blood volume decreases, mostly due to losses in breathing, the cold, dry air, chilled blood coming from your extremities begins to cool your “core”, the organs in your torso. This triggers a reflex that reduces the flow to your hands and feet, arms and legs, even your ears and nose, letting them get further chilled to conserve heat in your core. What little blood is flowing through the extremities becomes even more chilled, and even with the restricted flow, some of this blood mixes with that in your viscera and chills it even more. By this time you are probably shivering uncontrollably, as your body tries to generate some heat to keep you warm and, if you are lucky, someone is bringing you some hot chocolate to warm you up and, although they don’t think about it, some fluid to increase your blood volume.
It is true that you can be well hydrated and become hypothermic but, under similar conditions, the person who is more dehydrated will become chilled more quickly and thoroughly and recover much more slowly. Because water has such a high heat capacity, taking more energy to raise its temperature and requiring more energy loss to lower its temperature than almost any other substance, having a few more pints of fluid in your body means that you are going to conserve warmth longer. How many pints? Well, because cold air is much drier than warm air, you can lose more than two quarts (four pints) an hour while exercising vigorously in cold air and even more at altitude. This loss in blood volume costs you several calories per minute more than you would use to maintain the same body temperature. After four hours on the slopes, or the tracks, your judgement and coordination are affected, you have become irritable and have trouble making the effort to improve your situation.
Rangers in some of our National Parks and emergency response teams recognize this relationship and, in the winter, many carry a thermos of hot Vitalyte electrolyte replacement drink or people who have become hypothermic. Vitalyte is absorbed so quickly and is so effective that emergency medical teams call it “the oral IV”. The hot drink warms the viscera, raising your core temperature, and is absorbed so fast that you can feel the warm fluid flowing into your arms and legs, even your hands and toes, ears and nose! You should be drinking Vitalyte to maintain your fluid volume and avoid dehydration and hypothermia in the first place, and to avoid altitude sickness. Hot or cold, it can help you stay hydrated, keep warmer and enjoy your winter activities more, and more safely! Higher up = Hydrate up.