Answer:
Heat exhaustion
Explanation:
Heat exhaustion is an illness that can occur after you've been exposed to high temperatures and you haven't had the necessary rehydration under these conditions.
Although heat exhaustion is not that serious, if not treated it can progress to a heat stroke
The signs of heat exhaustion include:
Adam has been exposed to high temperatures for 90 minutes now, he's been mowing his yard and he probably didn't take much water. His symptoms include feeling faint and disoriented (confusion), excessive sweating and rapid pulse.
Considering the conditions he's been exposed to and his symptoms, he is most likely experiencing heat exhaustion.