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This paper describes the construction of a body cooling system to avoid heatstroke for survivors of cervical spinal cord injury. For accomplishment of this purpose, we chose the neck as a cooling point of the body, and we constructed a prototype neck cooling head with a refrigerated circulator. The neck cooling head was made by thin heat-welding thermoplastic films with high thermal conductivity. To test our proposed system, we conducted experiments on two unimpaired participants in a room which simulated a hot summer day (33 [°C], relative humidity 40%). Reduction of sweating were observed, and the average skin temperatures and the core temperature of the head with cooling increased more slowly than those without cooling. The estimated cooling power of the proposed system was about 10 [W] with 50 [W] total power consumption of the cooling head.

In this study, we attempted to develop a thermal model for estimating a body temperature in persons with spinal cord injury (SCI) during exercise. To clarify requisites for the SCI thermal model, we compared actual body temperature of SCI subjects with that calculated with a standard thermal model, that is, the Pierce two-node model. Model optimization by the parameter search method was able to fit the model-estimated skin and core temperature with those in able-bodied subjects during repeated exercise and rest. However, there remained a phase shift between actual and model-estimated core temperature trends in SCI subjects even after the optimization. The comparison of the optimized parameter combinations revealed that the Pierce two-node model was able to express loss of sweating in the SCI subjects, but unable to express delay in heat accumulation and dissipation. These results suggest that SCI thermal model requires additional nodes that express the speed and extent of heat transfer in the body of SCI persons.