抄録
Patients with hyperthermia have been increasing in recent years with the progress of global warming. Children and elderly tend to become hyperthermia for passive heat exposure and/or solar radiation. The reason for this tendency is considered as the morphological and functional differences between younger adults and children/older adults. In particular, children have morphological feature not only their height and weight are low but also they have a greater body surface area-to-mass ratio than that of the adults. The elderly has lower sweating rate as compared with the younger adults, while its mechanism is still controversial. In the present study, with numeric Japanese male and 3-year-old models, we analyzed core temperature elevation and perspiration in the adult and child phantoms for simultaneous solar and ambient heat exposure. At first, the threshold for activating the sweating in the older individuals was found to be about 1.5°C higher than that in the younger individuals by comparing the computational results with measured data. In addition, we found that core temperature elevation in the child model for solar and heat exposure was greater than that in the adult model, which is primary attributable to body surface area-to-mass ratio. Thus, the mechanism of hyperthermia in the elderly and child is different, although they are both sensitive to heat exposure as compared to younger adults.
