This accounts for the excessive rise in body temperature and it is the high fever which can cause permanent damage to internal organs, and can result in death if not treated immediately.
Recovery depends on heat duration and intensity.
The goal of emergency treatment is to maintain circulation and lower body temperature as quickly as possible. If the victim's condition does not improve or worsens, seek medical attention immediately Heat exhaustion starts with the accumulation of large quantities of blood in the skin in the the body's attempt to increase it's cooling efficiency. Usually this is due to temperatures conditions the individual is not accustomed to. This causes a loss of circulating blood volume which decreases the blood supply to the brain and can cause fainting. While this isn't as serious as heatstroke, the individual should be closely monitored.