describe what heat stroke does to the body and a situation where it's more likely to affect someone performing a physical activity.

The complications vary depending on how long the body temperature has been elevated

Explanation:

At extremely high temperatures, the body proteins and cell membranes, especially in the brain, begin to malfunction or be destroyed due to the lack of maintainging homeostasis.

At worst, heat stroke can cause Vital organ damage, or cause them to swell (especially the brain) causing permanent damage. Heat stroke can also cause the breakdown of the cardiac muscle cells and blood vessels.

So, in short, the longer the time spent in the sun or in a hot enviornment with no breaks, the worse the concequences from heat stroke are going to be.