How heat stress impairs cognition: A review of cognitive performance in indoor passive hyperthermal environments

Abstract

Hyperthermal indoor environments are receiving increasing attention due to the growing frequency of extreme heat events and the urban heat island effect. Because heat can be trapped indoors, resulting heat stress may impair cognitive performance and adversely affect health, productivity, and safety. Ensuring that all occupants remain within safe physiological limits is therefore essential to prevent heat-related illness. Despite the growing body of research in this field, recent reviews reflecting evidence on the cognitive impacts of indoor heat stress remain limited. To address this gap, this review focuses on indoor passive hyperthermal environments (air temperature of 30 °C or higher) in which occupants perform low-intensity activities typical of office and residential settings. In total, 13 experimental studies published after 2000 were examined, and the results indicate that: 1) a speed-accuracy trade-off occurs under heat stress, likely driven by psychological effects; 2) heat intensity and exposure duration interact to influence cognitive performance; 3) performance outcomes vary with task complexity, with complex tasks are more susceptible than simple tasks under identical conditions; and 4) human factors, such as age, gender, expectation and motivation, mental health condition, may modulate these effects. Accordingly, the authors suggest future research to integrate sensitive measures of brain activity with cognitive task under heat stress, as well as developing personalized mitigation strategies, such as tailored exposure limits, targeted cooling interventions, structured heat acclimation protocols, and environment-occupant matching recommendations.