Assessing Human Heat Stress Risk During Outdoor Summer Sports

Abstract

Exposure to extreme thermal environmental conditions for people engaging in outdoor sports and physical activity is projected to increase as global conditions worsen in the face of climate change. The broad objective of this thesis was to quantify both the personal and thermal environment to enhance biophysical modelling and reduce the risk of heat illnesses. Chapter III assessed the agreement in heat stress between nearby Bureau of Meteorology (BoM) stations and the playing surface of Cricket stadiums across Australia. The findings suggest that on-site monitoring reduces the frequency of misclassifying the heat stress risk, particularly at Major sporting venues where the inaccurate assessment of heat stress risk with BoM data is more frequent. Chapter IV examined the association between the evaporative requirement for heat balance (Ereq) and whole-body sweat rate (WBSR) in an outdoor environment; where our ability to calculate Ereq is challenged predominantly by the need to estimate key variables for calculating Ereq, without access to standard laboratory procedures and equipment. We observed a weaker association between Ereq and WBSR than previously seen indoors, with further evidence suggesting that the highest source of error in our calculation of Ereq outdoors, comes from uncertainties when estimating metabolic rate. Finally, chapter V compares the accuracy of available prediction equations for mean skin temperature (Tsk) during physical activity with measured Tsk data and develops a novel Tsk prediction equation that is suitable for use in high airflow environments (< 4.0 m·s-1), with high metabolic rates. Together, the findings from this thesis help to enhance extreme heat stress risk assessment by confirming the importance of on-site monitoring of thermal environmental conditions and through enhanced biophysical modelling during high-intensity physical activity in high airflow environments.