The night shift of heat: How real-world exposure and human diversity redefine vulnerability

Heat-health science remains dominated by daytime, outdoor metrics, yet recovery is lost at night and in indoor environments where heat actually accumulates. I argue that heat should be reframed as a 24-hour ecological exposure centred on nocturnal recovery and human diversity. Integrating sleep, mental health, metabolism, and sex-specific physiology into multimodal real-world monitoring offers a path to redefine exposure metrics and design fairer, more effective adaptation strategies for a rapidly warming world.