Previous research on heat stress (and associated physiological and psychological ramifications) has been carried out in controlled laboratory settings using primarily young, healthy male participants, and has tended to focus on either a physiological or psychological variable exclusively. Three basic conclusions have been derived from nearly five decades of this laboratory-structured research: 1) weight loss and hypohydration accompany increased wet-bulb/global temperature (WBGT), 2) heat stress has a pronounced effect on complex/dual tasks, 3) body core temperature is a valid predictor of heat stress.
A field study of heat stress investigating both physiological and psychological components was conducted with volunteer hazardous waste workers at the Hanford Nuclear Reservation to assess the conclusions of the laboratory research. Seventeen participants with a wide range of ages (25 - 56 years old) and states of health (Body Mass Index (BMI) 25-38) as well as both genders were tested for neurobehavioral indicators of heat stress (e.g. loss of alertness) with the Behavioral Assessment Research System (BARS), and for physiological indicators of heat stress (e.g. core and skin temperature, heart rate, blood pressure and ankle activity) using personal monitors (Mini-Mitters).
Initial indications from this study suggest that despite added variables found in the field two of the three conclusions listed above, were supported.