Degree Type


Date of Award


Degree Name

Doctor of Philosophy


Chemical and Biological Engineering

First Advisor

Richard C. Seagrave

Second Advisor

Mary Helen Greer


A model of the human body which integrates the variables involved in temperature regulation and blood gas transport within the cardiovascular and respiratory systems is presented in this dissertation. It expands upon previous work developed by the author to model the competition between skin and muscles when both require increased blood flows during exercise and/or heat stress. First, a detailed study of the control relations used to predict skin blood flow was undertaken. Four other control relations employed in the model were also examined and modified as indicated by empirical results found in literature;Several important cases were then examined where changing environmental conditions have an effect upon the functioning of these systems of the body. The model was also revised to account for immersion in a water environment and exercise in the water. It agrees well with experimental results in these cases;Additionally, it has been found that the activity level of the subject causes changes in physiological responses to exercise and/or heat stress. The model was modified to account for exercise training as well as various levels of heat acclimation, both before and after training. It was then validated to agree with experimentally derived results in these cases;Internal responses to exercise and/or heat stress can affect both thermoregulation and the cardiorespiratory system. Dehydration was studied in addition to complete water replacement during similar environmental and exercise situations. Control relations for skin blood flow and evaporative heat loss were modified and a water balance was added to study how the loss of water through sweat can be limiting. Run-off from sweating as a function of relative humidity was introduced along with evaporation, and these results were compared to data to validate the model. In the final section of this work, recovery from exercise was examined and again compared to empirical results.



Digital Repository @ Iowa State University,

Copyright Owner

Dawn Denise Downey



Proquest ID


File Format


File Size

120 pages