Preventing Illness and Injury
Dehydration And Hypokalemia

Background

What's so bad about dehydration? Ask Greg or Andrew, who got dehydrated the first day of their Troop's backpack over the Chilkoot Pass in Alaska. At about 4:00pm they collapsed. They could barely lift their heads off the ground for they lacked coordination. They vomited several times. They could keep nothing on their stomachs, not even a few sips of water. They were disoriented. Their skin was red and hot. They fainted several times. Their judgment was severely impaired.

Cause

How did this happen? They had been in an airplane much of the previous day (the re-circulated air in planes dries you out, as does the air in many hotels, as well as air conditioning generally). They had drunk little liquid the night before or that morning. They were tired from the prior sleepless night. They had one canteen each but they had been saving water for later in the day when "it might really get hot and steep".

Ordinarily when our body needs water it triggers thirst until we drink and get re-hydrated. But it is possible to lose fluid so quickly that the thirst mechanism is overwhelmed. How do we lose so much liquid? By respiration, perspiration and urination. Under normal daily activity a body loses 1-2 quarts from lung evaporation, 1-2 by perspiring and 1-2 from urinating. So the average loss is 4+ quarts. Now increase this by high adventure sweating and exercise, particularly in either/both cold or altitude. Now the fluid losses are up to 15 quarts; a 4-fold increase.

Dehydration - Prevention Is Simple

1) Tank up on liquid early in the day before your heightened activity starts. Don't forget the many high-liquid fruits and vegetables like melons, apples and oranges. 2) Take plenty of water on your trek and drink it incessantly. One quart is insufficient; take two and plan for refilling during the day, probably with filtering or chemical treatment. 3) Watch your urine. If it is not "clear and copious" you are not taking enough fluid.

A problem closely associated with dehydration is hypokalemia: potassium or electrolyte deficiency. Potassium is a mineral that is important to every major bodily function: blood pressure, regulation of cell water content, nerve impulses and digestion. Hypokalemia is caused by excess perspiration, which in turn is caused by high-level exercise in hot or humid conditions. The symptoms are: severe weakness, nausea, aching muscles, confusion and apathy. Because these are similar to the symptoms of both dehydration and hyperthermia, hypokalemia often goes undetected.

Prevention of Hypokalemia

The prevention is easy, but you have to remember to do it. Take in a daily load of potassium especially on a hot/humid/sweaty day. There are two easy ways to do this: 1) Eat a banana (or, not quite as easy, an avocado, an egg, some spinach, green beans, zucchini, asparagus, cantaloupe or orange juice). Or 2) drink at least a quart of some sports drink like Gatorade; these drinks are full of electrolyte replacements (for backpacking you can get them in powder form at sporting goods stores).