In NASCAR, temperatures in the car often exceed 100 degrees, reaching as much as 170 degrees by the floorboards. Drivers can lose 5-10 pounds in sweat during a race. If a driver loses more than 3 percent of his body weight in sweat and doesn’t replace those fluids, focus and reflexes start declining.
Before and during rainstorms many people will often experience pain in their bones. This is due to them having a more porous bone structure than the average person. As the air becomes more humidified the porous bones soak up the moisture in the air causing them to expand and cause pain to the surrounding muscle tissue.