Why Heat Deaths Occur During Low-Level Alerts: New University of East London Study

A groundbreaking study from the University of East London (UEL) has shed light on a perplexing trend in England: the majority of heat-related deaths happen during low-level yellow heat-health alerts, when the public is least likely to take protective action. Published in the journal Energy Research & Social Science, the research reveals deep gaps in awareness, understanding, and behavioral response to these warnings, leaving vulnerable populations exposed during what should be manageable heat events.

As climate change intensifies heatwaves across the United Kingdom, understanding why official alerts fail to prompt action is crucial. The study, titled "The heat is on: Understanding public responses to heat-health alerts in England," draws on a nationally representative survey of 1,097 adults conducted in August 2025. Led by researchers Angela Afua Assan, Dr. Fatemeh Khosravi (Senior Research Fellow at UEL’s Sustainability Research Institute), and Dr. Gloria Osei, it applies the Health Belief Model—a framework from public health psychology—to dissect how people perceive and react to heat risks.

Understanding the UK Heat-Health Alert System

The UK’s heat-health alerting system, operated by the UK Health Security Agency (UKHSA) in partnership with the Met Office, categorizes risks into four levels: Green for preparedness, Yellow for minimal impact but monitoring vulnerable groups, Amber for widespread health service strain, and Red for life-threatening conditions even for healthy people. Yellow alerts, the lowest active level, trigger essential actions in health and social care but often fail to resonate with the general public.

During yellow alerts, temperatures may not feel extreme, leading to complacency. Yet, UKHSA data shows significant mortality even then. In summer 2025, England recorded 1,504 heat-associated deaths across five episodes—higher than 1,311 in 2024 but lower than peaks in hotter years like 2022 (2,985 deaths). Over 90% of victims are aged 65+, with circulatory diseases and dementia as leading causes. Care homes see the sharpest rises, underscoring housing and care vulnerabilities.

Key Findings from the UEL Study

The survey uncovered stark disparities. Nearly 30% of respondents had never received a heat-health alert, a figure highest among older adults, low-income households, and those with lower education levels—precisely the groups most at risk. Among the 70% who had seen alerts, over 40% ignored them outright.

Response rates varied dramatically by severity: only 25% acted on yellow alerts, rising to 42% for amber and 72% for red. Miscomprehension was rife—65% correctly interpreted red alerts, but just 32% understood yellow ones. Common protective actions included using fans (73%) or air conditioning (23%), but 54% employed few strategies overall, hampered by economic barriers (42%), environmental constraints (38%), and psychological hurdles (37%).

• 91% expressed willingness to adapt during heatwaves, but actual behavior lagged (intention-behavior gap).
• Perceived severity, benefits, barriers, and self-efficacy strongly predicted action.
• Ethnic minorities (e.g., Asian/Asian British) showed higher vulnerability perception but lower response rates.

Dr. Mehri Khosravi emphasized, “Too many people are not seeing, not understanding, or not acting on heat alerts – and that is putting lives at risk.” The study, available here, calls for behavioral redesign of alerts.

Who Is Most Vulnerable and Why?

Heat vulnerability in the UK stems from demographic, socioeconomic, and environmental factors. Elderly individuals dominate statistics, comprising over 90% of deaths, due to physiological sensitivity, pre-existing conditions like heart disease, and isolation. UKHSA 2025 data pegged rates at 364 per million for 85+ and 116 for 75-84.

Low-income and deprived areas amplify risks through poor housing—80% of UK homes now overheat in summer, per recent reports. Ethnic minorities face higher odds, linked to urban density and cultural norms. Women, renters, and the unemployed show elevated responses but also barriers.

Digital exclusion compounds issues: older, low-income groups miss app-based alerts, relying on infrequent media. UEL’s findings align with broader research, like UKHSA’s noting circulatory and dementia deaths surging in care homes. For details on trends, see UKHSA’s 2025 report.

Photo by Toa Heftiba on Unsplash

The Science Behind Low Engagement with Alerts

Using the Health Belief Model, UEL researchers measured perceived susceptibility (personal risk: only 8%), severity (moderate for 66%), benefits of action, barriers, and self-efficacy (57% somewhat confident). Low personal risk perception drives inaction—people view heat as abstract until red alerts.

Yellow alerts foster false security; without clear, actionable steps, they’re dismissed. Socio-demographics matter: younger, employed women more responsive; renters and minorities perceive higher risk but face barriers. The study’s logistic regression showed economic barriers halving odds of action (OR=0.74).

This mirrors global patterns but highlights UK specifics: temperate climate dulls urgency, unlike Mediterranean nations.

Insights from UEL’s Sustainability Research Institute

UEL’s Sustainability Research Institute (SRI), home to lead authors, excels in climate adaptation. Dr. Fatemeh Khosravi, Energy and Carbon Senior Research Fellow, focuses on policy-behavior gaps. Angela Afua Assan, an architect and PhD researcher, explores built environment-heat links. Dr. Gloria Osei studies nature-based solutions for urban resilience.

Their work builds on UEL’s leadership in overheating policy, including reports on UK homes’ unpreparedness. SRI’s interdisciplinary approach—blending psychology, architecture, and public health—positions UEL as a hub for actionable climate research. For more, visit UEL’s study page.

Broader Context: Rising Heat Deaths in the UK

England’s heat mortality climbed: 2,985 (2022), 2,295 (2023), 1,311 (2024), 1,504 (2025)—despite cooler 2024. Climate change triples some events, per Imperial/LSHTM. Southern regions hit hardest; care homes amplify risks via poor ventilation.

Vulnerabilities intersect: deprived areas (higher mortality), urban heat islands, fuel poverty limiting cooling. Ethnic minorities 1.5-2x riskier due to housing/density. Adaptation lags—80% homes overheat, per 2025 studies.

Policy Recommendations and Solutions

UEL urges redesign: personalize alerts (highlight vulnerability), simplify language/actions, boost reach via non-digital channels (TV/radio for elderly). Target under-served: community leaders, GPs for low-income/older groups.

• Behaviorally informed messaging: emphasize benefits (e.g., “Fans cut risk 30%”).
• Address digital exclusion: printed guides, door-knocks.
• Integrate with housing retrofits—80% homes need cooling upgrades.
• Equity focus: deprived/ethnic areas via targeted campaigns.

UKHSA’s plan evolves, but UEL stresses urgency amid projections of doubled heatwaves by 2050s.

Photo by Andrea De Santis on Unsplash

Future Outlook: Enhancing Resilience

With UK summers warming 1.2°C since 1884, heat deaths could triple without action. UEL’s study paves way for adaptive communication, transferable to floods/cold snaps. Universities like UEL drive solutions—SRI’s policy influence aids UKHSA/Met Office.

Stakeholders must collaborate: government (clearer alerts), unis (research), communities (peer support). Proactive steps—affordable cooling, education—can save lives.

Conclusion: Time for Actionable Change

UEL’s research spotlights a preventable tragedy: low-level alerts failing vulnerable Brits. By bridging perception-action gaps, the UK can safeguard its most at-risk amid climate threats. Policymakers, heed the call—clearer, equitable alerts save lives.