Individual heat stress response
doctoral thesis
In 5 experiments, heterogeneous subject groups (large variations in _VO2 max, regular daily activity level, mass, body surface area (AD), % body fat, and AD/mass ratio) were tested for their physiological response while exercising on a cycle ergometer at a relative (45% _VO2 max; REL) or an absolute (60W; ABS) work intensity in a cool (CO; 21°C, 50% rh; REL condition only), warm humid (WH; 35°C, 80%) and a hot dry (HD; 45°C, 20%) environ-ment. Exposures lasted 90 minutes or until one of the safety criteria (Tre 39°C, 90% HRmax) was met. Physiological responses to the heat and work stress were subsequently analysed for the effects of the individual characteristics, in relation to the different work intensity types and the climate types. For this purpose, correlation analysis and multiple regression analysis were used. The analyses showed clear effects of individual characteristics, explaining between 10 and 72% of the variance (adjusted r²) depending on the test condition, _VO2 max and/or mass being the most relevant parameters. In parallel, individual characteristics were incorporated in a simulation model, using control functions from literature. Subsequently, the model was validated with the experimental data. The model was shown to produce results with similar accuracy, to that of the regression model derived from the data used. As the model was not derived from these same data, the validation result was considered successful.
Over all, the results showed that individual characteristics play a significant role in the determination of body core temperature response in all conditions tested, but their contribu-tion is low for relative work loads when evaporative heat loss is not restricted.
Over all, the results showed that individual characteristics play a significant role in the determination of body core temperature response in all conditions tested, but their contribu-tion is low for relative work loads when evaporative heat loss is not restricted.
TNO Identifier
8916
ISBN
90-9010979-X
Collation
189 p.