Heatstroke recovery at home as predicted by human thermoregulation modeling

Background: As global warming continues, incidences of heatstroke will become more prevalent. Since most deaths occur at home, timely and effective in-home treatment is critical to reduce heatstroke mortality. However, in-home treatment is limited by lack of knowledge and guidance. Objectives: To predict the course of heatstroke recovery over time for different home environment conditions, so as to provide useful information and technical guidance for heatstroke treatment. Methods: We suggested a new multi-node human thermoregulatory model by considering the effect of thermoregulatory impairment, delayed shivering and vasoconstriction, due to heatstroke on the course of recovery. The role of home environmental conditions in the course of heatstroke recovery was examined, to identify optimal treatment conditions. Results: Our thermoregulation modeling shows that the course of body core temperature during heatstroke recovery consists of three distinct stages: a rapid cooling stage due to vasodilation, a slower cooling stage due to vasoconstriction and a rewarming stage due to shivering. Our modeling results showed that hypothermia is a necessary condition for successful recovery, which cannot be achieved by the classical thermoregulatory model. We found that lower indoor temperature or higher ventilation can accelerate the cooling stage and that a higher indoor temperature or lower ventilation would be helpful in the rewarming stage, which indicated an optimal indoor condition for improving the recovery of heatstroke. To improve the chances of a full recovery, it is also necessary to carry out cooling treatment for a heatstroke patient as early as possible. Our new model was validated by rat experiments and the available human data. Conclusions: Onsite treatment of heatstroke should begin as early as possible. Our new thermoregulatory model can predict the course of body temperature changes overtime during heatstroke recovery, and hence may be used to develop effective in-home treatments.