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Shida N.1, Furukawa Y.1, Nitta O.1, Kinoshita M.1, Kuruma H.1, Kamio H.1, Ikeda Y.1
1Tokyo Metropolitan University, Human Health Sciences, Arakawa, Japan
Background: Due to sympathicopathy, individuals with spinal cord injury cannot dissipate heat via vasomotion and perspiration; thus, heat gets accumulated in their bodies.
Purpose: This study aimed to measure body temperature and heart rate changes while playing wheelchair sports under hot environments and compare them among those with different levels of injury.
Methods: Subjects included nine individuals with a cervical spinal cord injury who play wheelchair rugby, with a mean age of 25.5 (SD 3.89) years (hereafter referred to as the higher group), and 12 individuals who play wheelchair basketball, with a mean age of 28.6 (SD 3.89) years (hereafter referred to as the lower group). Subjects of both groups were asked to wear heartbeat sensors during practice
(Polar Team Pro: Polar Electro Japan).
The average number of heart beats per minute before practice was considered as the heart rate at rest, and the highest heart rate during practice was considered as the maximum heart rate. Pictures of facial surface temperatures (°C) before and immediately after practice were taken using an infrared thermography camera (InfReC R300: Nippon Avionics Co., Ltd.), and the maximum values were used as body surface temperatures. For statistical analysis, a two-way factorial analysis of variance and a test of simple main effect using the Bonferroni method were performed. IBM SPSS ver.22 was used for analysis, and the level of significance was set at 5%.
Results: The average heart rate (SD) of the higher group was 78.0 (8.94) beats/min at rest and 138.4 (14.48) beats/min at maximum. The average heart rate (SD) of the lower group was 91.4 (5.84) beats/min at rest and 181.2 (7.89) beats/min at maximum. Interactions were significant, and changes in heart rate caused by physical activities were significantly different between the higher and lower groups. In the simple main effects, all combinations of the values at rest and at maximum and of the higher and lower groups were significant.
The average body surface temperatures (SD) of the higher group were 35.6 (0/86) °C before practice and 36.9 (1.05) °C after practice, and those of the lower group were 36.1 (0.91) °C before practice and 36.5 (0.72) °C after practice. Interactions were significant. The differences in simple main effects between before and after practice in the higher group and between the higher and lower groups after practice were significant.
Conclusion(s): The maximum heart rate of the higher group was significantly low. This suggests that the increase in heart rate was suppressed by the disorder of sympathetic nerve regulation from the upper central nervous system to the heart.
The increase in body temperatures was more in the higher group than in the lower group under hot environments, indicating that risk of hyperthermia was high.
Implications: It is socially meaningful to clarify the effects and risks of sports and improve sport environments for physically impaired persons.
Funding acknowledgements: This study was supported by the research funding of Tokyo Metropolitan University.
Topic: Sport & sports injuries
Ethics approval: This study was approved by Tokyo Metropolitan University Ethical Review Board.
All authors, affiliations and abstracts have been published as submitted.
