Systematic review of the effectiveness of heat-health protection interventions

Background

Due to increases in the frequency and intensity of extreme heat, interventions are needed to reduce heat-related mortality, morbidity, and demand for emergency services. However, evidence on the effectiveness of heat-protection measures is missing.

Methods

Following a protocol, which was co-produced with an international expert panel (CRD420251020849), we conducted a systematic review. We searched PubMed, Embase, Web of Science, and Google Scholar from inception to February 2026, and grey literature. Experimental and observational studies assessing the effect of heat-protection interventions on mortality, morbidity and emergency demand in the general population or in heat-vulnerable groups were included. Risk of bias was assessed with the JBI checklist. Where studies were sufficiently comparable, we conducted random-effects meta-analysis; otherwise, findings were synthesised narratively.

Results

Of 32,149 records screened, 49 studies were included. Most studies evaluated complex interventions, particularly heat-health action plans (HHAP; n = 18) and heat warning systems (HWS=12). Fewer studies assessed urban and building planning measures, education and awareness campaigns, community interventions, occupational interventions, and emergency preparedness measures. Mortality was the outcome reported most. In meta-analysis of pre–post studies, HHAP implementation was associated with reduced mortality risk (RR = 0·93 [95% CI 0·89; 0·99], p < 0·05). Evidence for HWS was inconsistent. Three studies suggested that air conditioning in public institutions was associated with lower mortality risk than no air conditioning. Evidence for other interventions was limited or inconsistent.

Conclusions

Comprehensive HHAP appear to reduce heat-related mortality, but evidence for HWS alone and other intervention types remains limited. More rigorous evaluations are needed, particularly for morbidity, emergency service demand, and in low-resource settings.

Key messages

• Heat–health action plans are associated with reductions in mortality, with some evidence indicating that these effects may be stronger among older populations.

• These findings support current policy recommendations, emphasising comprehensive, multi-component approaches to heat adaptation.