What causes sunstroke?
In a hot environment, your body rids itself of excess heat through increasing blood flow to the skin, sweating and breathing out warmed air. These mechanisms can sometimes be overwhelmed, however, leading to heat-related symptoms, which, if left untreated, can lead to sunstroke. When blood temperature rises above its normal range, a control centre in the brain (the hypothalamus) signals the circulatory system to increase blood flow and enlarge the blood vessels, particularly those in the skin. As more blood flows through the enlarged vessels, excess heat from the blood passes into the cooler air. If this is not sufficient to cool the blood, the sweat glands begin to produce sweat, which cools the skin as it evaporates. If the air temperature is very high, however, the blood may not cool down enough as it circulates through the skin. Also, when you lose too much fluid, the blood volume decreases, and body temperature increases. If the body continues to generate heat faster than you can
