The body temperature may be higher than 104 degrees Fahrenheit. Sweating is often absent, but the skin may be quite moist from earlier perspiration. The core temperature must be brought down immediately. In runs, perspiration is usually noted, and you do not need the absence of perspiration , with the pulse noted to be faster than 160. The blood pressure may be low.
Liver damage is also evident when liver enzymes are measured following heatstroke.
Rapid medical attention is vital. After exercise drink more fluid than you think you need. Especially if you are over 40. Your thirst mechanism, does not appear to be as effective a gauge of your water needs as you age. Make sure you are aware of both medical conditions that you have and medications that can affect your tolerance of exercise in the heat.