Prioritize research on human behaviour during extreme heat

Humans are impressively able to withstand exposure to extreme heat through behavioural and physiological mechanisms, which suppress internal heat generation, limit environmental heat gain and augment heat loss. During heat stress, elevations in body temperature redirect blood to the skin surface and increase sweat loss, reducing blood pressure and plasma volume, which increases cardiovascular demand. Consequently, prolonged heat stress can lead to fatal cardiac events and kidney injury, as well as heat stroke. However, protective cooling and hydrating behaviours can be very effective at reducing rises in body temperature and cardiovascular demand, while preserving body water. We argue that behaviour is our most powerful way of mitigating negative health effects of extreme heat, but this can be modulated by access, motivational conflict and interactions between physiology and perception...