An automobile engine needs coolant to keep it from overheating. If the radiator runs dry, the engine can be ruined.
Bad things happen to people, too, when their fluid levels are low. Blood thickens and becomes more difficult for their hearts to pump. They can feel tired, irritable, and perhaps nauseous. That's called heat exhaustion. Treat it with rest in the shade and sips of water.
Heat stroke strikes when the body's cooling mechanism is so overworked it stops functioning. That's a life-threatening emergency. Cool the victim however you can-with shade and wet cloths, for example, or the air-conditioner in a car. Get medical attention as soon as possible.
Of course, the best way to deal with heat illnesses is to avoid them in the first place. Plan your activities so that you carry all the water you need, or can replenish your supplies along the way.
Drink, Drink, Drink
Thirst is not always the best indicator of your body's need for water. Instead, drink often enough for your urine to remain light-colored or clear.
In hot weather, refresh your water containers at every opportunity. Drink your fill, then refill your container before leaving a water source.
Keep water readily available and drink small amounts frequently.
Don't ration water. If you are thirsty, you need to drink.
Avoid consuming a lot of caffinated drinks, which can act as diuretics -- agents that purge fluids from the body.
Don't underestimate your need for water. During strenuous activities in hot weather, your body might require two to three gallons of water per day.
Remember that carrying water with you isn't enough. You need to drink it, too, in order to stay happy, healthy, and hydrated.
For more information, consult Chapter 14, "Hot-Weather Travel and Camping," of the BSA Fieldbook, Fourth Edition.
