What condition should be suspected in a hiker experiencing light-headedness, low blood pressure, and sweating after prolonged exertion?

In this scenario, heat exhaustion is the condition that should be suspected due to the classic symptoms presented by the hiker: light-headedness, low blood pressure, and sweating after prolonged exertion. Heat exhaustion occurs when the body's cooling system becomes overwhelmed, often due to high temperatures and intense physical activity, leading to the body losing a significant amount of water and electrolytes through sweat.

The combination of low blood pressure and light-headedness suggests that the hiker is experiencing systemic effects of dehydration and potential heat injury. Sweating is a key indicator because it suggests the body is attempting to regulate its temperature. However, if the fluid loss isn't compensated by adequate hydration, it can lead to more severe symptoms, including fainting or collapse.

While heat stroke is a more severe condition characterized by a high body temperature, confusion, and potentially loss of consciousness, the individual in this case is showing signs consistent with heat exhaustion rather than the more dangerous heat stroke. Dehydration alone may lead to similar symptoms, but it does not typically induce the degree of sweating described. Hypothermia is not applicable here, as it is associated with cold exposure and presents with different symptoms. Thus, heat exhaustion is the most fitting diagnosis for this situation.