Answer:
Heatstroke can result in a number of complications, depending on how long the body temperature is high. Severe complications include:
Vital organ damage. Without a quick response to lower body temperature, heatstroke can cause your brain or other vital organs to swell, possibly resulting in permanent damage.
Death. Without prompt and adequate treatment, heatstroke can be fatal.
it is more likely to effect someone performing a physical activity as the person's temperature is already high due to body movement.