What component does not factor into the Heat Stress Index calculation?

The Heat Stress Index (HSI) is a measure used to assess the risk of heat-related illnesses based on environmental conditions. It is a composite index that considers several environmental factors that affect how hot it feels to the body.

Core body temperature is not included in the calculation of the Heat Stress Index because the HSI primarily assesses environmental conditions, not physiological responses of the body. The index is calculated based on external factors, such as radiant temperature, air velocity, and humidity—all of which impact how heat is absorbed or dissipated by the body.

Radiant temperature accounts for heat from nearby surfaces and sun exposure, air velocity affects heat loss through convection, and humidity levels determine how effectively sweat can evaporate from the skin. Therefore, while core body temperature is critical for understanding an individual's response to heat, it does not factor into the HSI itself, as the index aims to predict heat stress based on environmental conditions rather than internal physiological conditions.