Heat stress refers to the human body’s inability to maintain a normal temperature because of conditions such as high temperature and humidity. Certain jobs or activities require people to be subjected to these conditions, which may put their bodies at risk of heat-related illnesses and possibly result in death. Heat-related illnesses include heat cramps, heat exhaustion, and heat stroke.
Typical temperature measurements require an aspirated shield to prevent direct solar radiation from skewing the measurements. In contrast, direct solar radiation is required as a component to measure environmental heat stress.