Dehydration and heat-related illness have long been common causes of mortality in outdoor situations. In 1967, during the Israeli-Egyptian war, 20,000 Egyptians died due to dehydration. However, there were minimal deaths of Israelis. This was partly due to the fact that the Israelis were prepared. They each had 5 gallons of water per day to drink, to replenish their fluid supply.
Dehydration is defined as sweat, urine or respiratory water loss. It results from the voluntary restriction of intake of water. Thirst is not a good indicator for when to replace water. This has been seen in marathon runners who are accustomed to running long distances and have conditioned themselves thusly so. When endorphins take over, the thirst mechanism is disregarded. So being thirsty is not a good indicator for how dehydrated one might be.
Dehydration also decreases work performance. They body is between 45%-75% water. The average 160 lb. male contains about 45 liters of water, or 6% of his body weight. Thirty liters of that is intercellular and 15 liters is extracellular. Water moves freely from compartment to compartment. You can lose 2% of your body weight before thirst is initiated, which may get worse as the severity of dehydration increases. With 4%-6% body water loss, you are anorexic, impatient and you have symptoms of headache. With 10% loss, you have dizziness and become light-headed. With 12% loss, you have difficulty swallowing and you require assistance in re-hydration. 15%-25% water loss is lethal.
Dehydration produces a decrease in ability to stay alert. Your power can decrease 6% and time performance by 12% in the heat. Sweat rates can be as high as 1-1/2 liters per hour, or roughly 15 liters a day. Water requirements are not only imperative in the heat, but they are imperative in the cold. They are also higher than most people believe. At high altitudes, water requirements can be very similar to those in the desert. Some very rough estimates for water replacements in the cold: Approximately 2 quarts per day, severe cold with heavy exercise, up to 2 gallons. Altitudes above 10,000 feet, definitely more than 2 gallons.
You want to be able to urinate pale yellow. If you can’t remember the last time you urinated, you are significantly dehydrated. Drink by your watch in hot environments. Forced drinking in the absence of thirst saves lives in the heat.
Dehydration and heat exhaustion and stroke can be very dangerous. In the outdoors it cannot be stressed enough.
If you know wilderness in the way that you know love, you would be unwilling to let it go.... This is the story of our past and it will be the story of our future."
—Terry Tempest Williams
"If future generations are to remember us with gratitude rather than contempt, we must leave them something more than the miracles of our technology. We must leave them a glimpse of the world as it was in the beginning, not just after we got through with it."
—President Lyndon B. Johnson,
upon signing The Wilderness Act of 1964
Dehydration is defined as sweat, urine or respiratory water loss. It results from the voluntary restriction of intake of water. Thirst is not a good indicator for when to replace water. This has been seen in marathon runners who are accustomed to running long distances and have conditioned themselves thusly so. When endorphins take over, the thirst mechanism is disregarded. So being thirsty is not a good indicator for how dehydrated one might be.
Dehydration also decreases work performance. They body is between 45%-75% water. The average 160 lb. male contains about 45 liters of water, or 6% of his body weight. Thirty liters of that is intercellular and 15 liters is extracellular. Water moves freely from compartment to compartment. You can lose 2% of your body weight before thirst is initiated, which may get worse as the severity of dehydration increases. With 4%-6% body water loss, you are anorexic, impatient and you have symptoms of headache. With 10% loss, you have dizziness and become light-headed. With 12% loss, you have difficulty swallowing and you require assistance in re-hydration. 15%-25% water loss is lethal.
Dehydration produces a decrease in ability to stay alert. Your power can decrease 6% and time performance by 12% in the heat. Sweat rates can be as high as 1-1/2 liters per hour, or roughly 15 liters a day. Water requirements are not only imperative in the heat, but they are imperative in the cold. They are also higher than most people believe. At high altitudes, water requirements can be very similar to those in the desert. Some very rough estimates for water replacements in the cold: Approximately 2 quarts per day, severe cold with heavy exercise, up to 2 gallons. Altitudes above 10,000 feet, definitely more than 2 gallons.
You want to be able to urinate pale yellow. If you can’t remember the last time you urinated, you are significantly dehydrated. Drink by your watch in hot environments. Forced drinking in the absence of thirst saves lives in the heat.
Dehydration and heat exhaustion and stroke can be very dangerous. In the outdoors it cannot be stressed enough.
If you know wilderness in the way that you know love, you would be unwilling to let it go.... This is the story of our past and it will be the story of our future."
—Terry Tempest Williams
"If future generations are to remember us with gratitude rather than contempt, we must leave them something more than the miracles of our technology. We must leave them a glimpse of the world as it was in the beginning, not just after we got through with it."
—President Lyndon B. Johnson,
upon signing The Wilderness Act of 1964
