THE first heat health impact reports published in Wales demonstrate that ‘heat events’ such as heat waves, hot nights, moderate heat and cumulative heat have strong associations with increased morbidity and mortality, and recommends that more research is done in Wales to develop ongoing evidence of the impact of heat on health.

In addition, the reports show that these events have a disproportionately greater impact on vulnerable groups such as older adults, children, socioeconomically deprived communities, and some ethnic minorities. Factors such as air pollution and humidity often amplify the impact of heat.

Around times of greater heat events in the summer of 2024, the reports show that there was an 83 per cent increase in children attending A&E for gastrointestinal issues, a 90 per cent increase in A&E attendance for ‘psychological/psychiatric’ issues in urban areas, and an increase in 999 calls for fitting. There were also increased GP consultations for heatstroke.

Even short heat events were associated with increased mortality in Wales – while there was no national heatwave, a brief heat period from July 28 to August 2 did result in a statistically significant risk in daily deaths, particularly among older adults and urban population. During this period the mean daily mortality was 93 deaths, compared to 84 deaths outside the heat period. However, the report recommends that more research is needed to identify that the increased deaths were caused by heat.

The three reports are an interim suite of publications from the Integrated Climate and Environmental (ICE) Surveillance Team, within Public Health Wales’s Communicable Disease Surveillance Centre (CDSC), Health Protection Division, and aims to identify the heat exposures most likely to lead to an increase in adverse health outcomes, and examine the health indicators that show the extent of heat-related morbidity and mortality.

Examining the impact of increased heat on health is particularly important now as in Wales, the ten hottest years on record have all happened since the early 2000s, and projections indicate that this warming trend will increase. Increased temperatures will likely lead to more frequent, intense, and prolonged heat events, which is expected to increase pressure on health and social care systems in Wales, and there is a need for tailored evidence and surveillance on heat-related morbidity and mortality to plan effectively.

Improved heat-health surveillance would support Wales’ wider work to protect communities from the health harms linked to a warming climate.

Dr Behrooz Behbod, Consultant Epidemiologist at Public Health Wales, said: “As the climate warms globally, heat events will be more frequent and will likely cause more health-related impacts. By measuring the impact specifically on the health and care services in Wales then services will be able to be planned more effectively to enable greater resilience in future years.

“Other countries such as France, USA, and Australia have developed advanced surveillance systems based on more complex modelling, and we can learn a lot from these countries and adapt their methods to a Welsh context in our efforts to support climate adaptation work.”