WHO issues new guidance to prevent heat-related illness at mass gatherings

The World Health Organisation (WHO) has released new guidance to help governments and event organisers prevent and manage heat-related illness at large gatherings, including sporting, religious and cultural events

As extreme heat becomes more common, health and operational risks at large gatherings continue to rise.

WHO says many heat-related illnesses at major events can be prevented or treated on-site with appropriate planning and medical support.

Nearly half a million medical encounters reviewed

The new guidance is based on an evidence review covering studies published between 1980 and 2025. The research examined almost half a million medical encounters at mass gatherings, including more than 22,000 cases of heat-related illness.

The evidence also found that well-organised on-site medical services can treat more than 90% of patients at event venues. This can reduce pressure on local hospitals and ambulance services, particularly when large numbers of people attend an event.

WHO says heat risks at mass gatherings can increase with long periods outdoors, direct exposure to sunlight, crowded spaces, limited access to drinking water and toilets, and travel-related stress. Visitors may also be unfamiliar with local weather conditions, while emergency services can face additional demand.

A growing threat from extreme heat

The WHO released guidance amid growing concerns about the health impacts of rising temperatures. The organisation estimates that heat-related deaths have increased by 63% since the 1990s, with an average of 546,000 deaths recorded each year between 2012 and 2021.

The Intergovernmental Panel on Climate Change has also reported that hot extremes and heatwaves have become more frequent and intense across most land regions since the 1950s. Further increases are expected as global temperatures rise.

Planning ahead can reduce risks

WHO recommends that organisers take a whole-of-event approach to heat management rather than relying solely on individuals to protect themselves.

Key measures include providing safe drinking water and adequate toilets, creating cooling areas and infrastructure, adjusting event schedules, managing crowd movement and protecting workers from heat exposure.

Organisers are also encouraged to use public communication, real-time health surveillance and well-prepared on-site medical services.

The guidance covers the full event cycle, from planning and preparation through the event itself and emergency response.

WHO says heat risk management should be incorporated into wider emergency preparedness and health planning. The new resources are designed to complement national heat-health action plans, occupational health and safety requirements and existing emergency preparedness arrangements.

The organisation is calling on governments, event organisers, and partners worldwide to make heat risk management a core part of mass-gathering planning.