Heat stress has been a topic of military research for over half a century. It has been managed largely as a technical and medical problem. This approach frames heat stress management as a response to environmental conditions. As a result, in practice, heat management protocols may be ignored in favour of achieving a mission. This chapter draws on emergent, cross-disciplinary research that combines thermal physiology with Social Practice Theory, in order to make two related conceptual arguments. First, if heat stress emerges at the interface of activity and the environment, operational activities themselves all inherently shape heat stress. This makes all of the drivers of heat stress more visible, thereby opening up the times, spaces and ways in which heat stress can be prevented, mitigated and managed. Second, heat management goes beyond tactical decisions; it can have strategic and operational implications. We close by briefly considering what such thinking means for military personnel and for society more broadly.