Managing body temperature during hot and humid conditions can be challenging for many athletes. For individuals with a spinal cord injury (SCI), it may be of even greater concern due to an impaired ability to thermoregulate in the heat. A lesion to the spinal cord results in disruption to the autonomic nervous system, and consequently impaired skin blood flow and sweating control, both essential for preventing potentially dangerous rises in core temperature. Limitations in previous experimental designs have prevented a clear understanding of the influence of SCI level on thermoregulatory capacity in the heat. Therefore, the aims of this thesis were to establish the independent influence of SCI level on thermoregulation during exercise and the consequences for thermoregulatory recovery following exercise in the heat, identify key considerations for monitoring individuals with a SCI in the field, and explore the impact of drink temperature on thermoregulation during exercise. The findings of this thesis indicate athletes with tetraplegia and high paraplegia experience the most impaired ability to thermoregulate during exercise in the heat whereas athletes with low paraplegia demonstrate similar core temperature and sweating responses to able-bodied individuals. Furthermore, there was reduced variability in the association between changes in core temperature and SCI level compared to previous investigations once differences in participant body size and fitness were accounted for in the prescription of exercise intensity. Following exercise, it is apparent that impaired evaporative cooling, secondary to an absent or limited sweat response, is responsible for the inability to dissipate heat generated in the prior exercise bout in those with a high SCI. Gastrointestinal temperature does provide an accurate means of monitoring athletes with a SCI during and following exercise in the field, however there is a clear instrumental delay in the responsiveness of core temperature at this site, such that peak core temperature may occur after exercise has ceased. Furthermore, perceptual ratings should not be used in isolation to determine level of thermal strain in athletes with a SCI as it does not always align with physiological strain. Finally, cold fluid ingestion may be a particularly beneficial cooling strategy for individuals with a SCI, however the influence of drink temperature on local sweating and core temperature responses is inconclusive based on current data and requires further exploration. Collectively this research furthers the understanding of thermoregulation in athletes with a SCI and proposes best-practice strategies for monitoring and individualising heat management strategies in the field. Specifically, it is recommended to monitor athletes with a high SCI (athletes with tetraplegia and high paraplegia) during exercise in the heat, and to continuing to monitor these athletes post-exercise until a reduction in core temperature is observed (at minimum). Furthermore, the data in this thesis also reinforces the importance of implementing cooling strategies with these athletes to ensure safety is not compromised during heat exposure.
Thermoregulation in the heat in athletes with a spinal cord injury
Maloney, P. (Author). 2021
Student thesis: Doctoral Thesis