Mapping the socio-technical causes of overheating risk and unequal thermal burden in hospitals in England: a qualitative systems inquiry using AcciMap

Background Hospital overheating arising from more frequent heatwaves threatens healthcare staff wellbeing, patient safety and service continuity, but is often managed as an estates or seasonal problem. We examined how interacting organisational, infrastructural and experiential conditions sustain overheating vulnerability and unequal thermal burden in hospitals in the south of England. Methods We conducted a six-phase, multi-source qualitative systems inquiry integrating 129 overheating incident reports from two National Health Service (NHS) hospitals in Hampshire, England, six stakeholder interviews, two focus groups with healthcare staff and patients (n=12), and a national stakeholder refinement focus group (n=4). AI-supported thematic analysis was combined with context-mechanism-outcome synthesis and iterative AcciMap construction, to produce an integrated systems explanation. Results Twenty themes were consolidated into six interacting explanatory pathways: 1) recognition without durable resilience; 2) hidden visibility; 3) workaround-based resilience; 4) unequal adaptive capacity; 5) underuse of emergency preparedness and business-continuity systems; 6) institutional framing. The analysis indicated that, within the hospital settings investigated, overheating persisted despite recognition because ownership, information, resources and delivery capacity were fragmented across system levels. Frontline workarounds sustained care but could conceal thermal burden and defer structural adaptation. Staff and patients had unequal capacity to regulate exposure because of differences in mobility, autonomy, physiology, clinical dependency and occupational role. Existing preparedness systems offered a route from seasonal reaction to anticipatory action, but overheating was not consistently embedded within them. The AcciMap showed how shared factors connected the six pathways and identified coordinated intervention entry points across monitoring, governance, preparedness, service delivery and infrastructure. Conclusions Overheating in hospitals in England is best understood as a socio-technical patient-safety and adaptation challenge, not a single-domain estates problem. Our analysis indicates that durable resilience requires environmental intelligence linked to accountable decisions, support for staff and patient adaptation, activation of preparedness systems and long-term infrastructure change.