Identify three risk factors for heat-related illness.

• A. Altitude, CO exposure, noise.
• B. Moderate temperature, low humidity, light activity.
• C. High temperature, high humidity, heavy physical workload.
• D. Low temperature, low humidity, sedentary work.

Answer: (C)

Heat stress risk rises when the body faces a high heat load and limited ability to dissipate it. The combination of very hot air, high humidity (which makes sweating less effective), and a heavy physical workload (which increases internal heat production) creates the strongest conditions for heat-related illness. High ambient temperature drives the baseline heat exposure, humidity reduces evaporative cooling, and heavy work amplifies metabolic heat, together elevating the risk significantly.

Other options don’t fit because altitude with CO exposure and noise doesn’t directly add to heat load in the same way; a scenario of moderate temperature with low humidity and light activity reduces heat strain; and low temperature with low humidity and sedentary work presents minimal heat stress rather than a risk.