Mathematical models of human thermoregulation can be used to assess the
habitability of thermal environments prior to human exposure. Work continues to
improve the performance of these models to reduce concerns surrounding the accuracy
of their predictions. The aims of this thesis were to develop an existing
thermoregulatory model (LUT25-node model).
The developments made to the LUT25-node model, now enable it to predict the
thermal responses of heat acclimated subjects of differing size, while its clothing
model was improved to consider the addition and distribution of clothing properties.
Validations of these modifications, confirmed that predictions from the model were
The thesis also looks at practical applications of the LUT25-node model. This
included a modification to the model enabling backward modelling; predicting how
the thermal stress should be altered to achieve a desired limit of thermal strain.
Several hypothetical scenarios illustrated the practical applications of this
modification. In addition, the LUT25-node model was used to explain the initial drop
in deep body temperature at the onset of exercise. This investigation concluded that
the temperature drop is due to the return of cool blood to the body core from initially
cool working muscles.
Finally, the poor predictions of the LUT25-node model for cold exposures was
investigated. Previous investigators suspected that this was due to the limited number
of thermal layers in the body segments of the model. However, predictions from a
multi-layered LUT25-node model, developed with the finite volume software package
PHOENICS, suggest that increasing the number of thermal layers reduces the
accuracy of the model's predictions for cold exposures.
In conclusion, this thesis has contributed to the continued development of a human
thermoregulatory model and illustrated its practical benefits. It is recommended that
future work centres on addressing additional limitations of the LUT25-node model
identified in this study.
A Doctoral Thesis. Submitted in partial fulfillment of the requirements for the award of Doctor of Philosophy of Loughborough University.