Sustainable Governance of Extreme Heat Risk in the Context of Occupational Safety and Health

Extreme heat disrupts labour, infrastructure, and health systems, yet most response frameworks intervene after clinical impact is confirmed. This review analyzes documented cases across sectors and regions to determine where heat effects are first detected and why intervention timing varies. The analysis used institutional reports, epidemiological summaries and occupational data to map how early functional signals appear across systems. A conceptual matrix is proposed to permit action to be authorized at the earliest sign of functional stress, using mortality, productivity, service instability, vulnerability, and adaptive capacity as operational inputs rather than retrospective outcomes. The analysis suggests that heat becomes observable first through reduced work capacity or infrastructure strain, not through hospital data, and that systems with predefined activation criteria engage earlier and with less irreversible loss. The matrix provides a transferable basis for integrating occupational, infrastructural, and clinical information into a unified heat response mechanism. This approach supports a transition from post-impact validation to forward-based decision logic, particularly in settings where vulnerable workers remain outside formal surveillance.