Development of a simple apparent temperature model in hot and cold outdoor work environments

This study develops and evaluates a modified apparent temperature (MAT) model, validates this model with physiological data reported in the literature and with Goldman's model of physiological responses. A simplified MAT (SAT) model is also developed.

The primary results of the study were:

1. Explanation of the apparent temperature (AT) model;
2. Development of a modified apparent temperature (MAT) model;
3. Validation of the modified apparent temperature (MAT) model using physiological data from literature;
4. Evaluation of the modified apparent temperature (MAT) model by comparing it with the physiological heat transfer model (Goldman's model);
5. Simulation of the MAT model over the wide range of thermal conditions;
6. Performance of a sensitivity analysis of components in the MAT model; and
7. Simplification of the modified apparent temperature model (SAT). Results indicate that an apparent temperature model provides a valid representation of the physiological responses to a thermal environment. The MAT model can be simplified into a two-parameter SAT equation with a reasonably small loss in accuracy.

This study supports the concept that AT is not only useful as an indicator of how a temperature feels, but it also meaningfully corresponds to changes in deep body temperature and thus potential heat stress.