WHO Issues New Guidance to Prevent Heat Related Illness at Mass Gatherings

The World Health Organization (WHO) has released new guidance aimed at helping governments and event organizers prevent and manage heat-related illness at large sporting, religious and cultural gatherings, as rising temperatures and more frequent extreme heat events create growing risks for spectators, participants, volunteers and workers.

The new recommendations draw on an extensive review of evidence published between 1980 and 2025. According to WHO, the research documented nearly 500,000 medical encounters at mass gatherings, including more than 22,000 cases of heat-related illness.

One of the key findings is that many heat-related medical problems at major events can be prevented or managed without transferring patients to hospitals when organizers have appropriate preparedness and on-site medical systems in place.

Studies reviewed by WHO found that with well-organized medical services, more than 90% of patients requiring medical attention could be treated at the event venue, helping reduce pressure on local hospitals, emergency departments and ambulance services.

Extreme Heat Is Becoming an Operational Risk for Major Events

WHO warns that extreme heat should no longer be viewed solely as an environmental concern. For organizers of large-scale events, it is increasingly becoming an issue of public health, safety and operational continuity.

Dr. Chikwe Ihekweazu, Executive Director of the WHO Health Emergencies Programme, said protecting people from extreme heat cannot depend only on individuals changing their own behavior.

Instead, event organizers and authorities need systematic approaches to risk assessment, preparedness and emergency response so that major gatherings can operate more safely as global temperatures rise.

The issue is becoming increasingly significant as heat-related mortality rises worldwide. WHO's new guidance cites estimates indicating that heat-related deaths have increased by approximately 63% since the 1990s, with an average of about 546,000 deaths annually between 2012 and 2021.

Why Mass Gatherings Can Increase Heat Risks

Major events can create conditions that amplify the health effects of hot weather.

Spectators and workers may spend hours outdoors under direct sunlight, while large crowds can restrict airflow and make it more difficult to access shaded or cooler areas.

Limited access to safe drinking water, travel-related fatigue, alcohol consumption in some settings, unfamiliarity with local weather conditions and pressure on medical services can further increase risks.

People attending events away from their home countries or regions may also be less accustomed to local temperatures and humidity.

These factors are particularly relevant for international sporting competitions, concerts, festivals, religious gatherings and other events attracting large numbers of visitors.

Climate Change Is Increasing Exposure to Extreme Heat

The new guidance comes as extreme heat becomes more frequent and intense in many parts of the world.

According to the Intergovernmental Panel on Climate Change (IPCC), hot extremes, including heatwaves, have become more frequent and more intense across most land regions since the 1950s, with human-caused climate change identified as the main driver.

The frequency and intensity of extreme heat are expected to continue increasing with every additional increment of global warming.

This changing climate means that heat preparedness is becoming increasingly important not only for countries traditionally associated with hot weather but also for destinations and cities that may previously have experienced extreme temperatures less frequently.

WHO Recommends Eight Key Areas of Heat Preparedness

WHO's recommendations emphasize that effective heat protection requires several measures to work together rather than relying on a single intervention.

Key measures identified in the guidance include:

• providing easily accessible and safe drinking water and adequate toilets;
• establishing cooling infrastructure and shaded or cooler spaces;
• adjusting event schedules when heat conditions create elevated risks;
• improving crowd-flow management;
• introducing appropriate heat-protection measures for workers and volunteers;
• communicating heat risks and preventive advice clearly to the public;
• using real-time surveillance to identify changing health risks; and
• ensuring well-prepared medical services are available at event venues.

Together, these measures can help organizers identify problems earlier, reduce exposure to dangerous conditions and respond rapidly when attendees begin experiencing symptoms of heat-related illness.

Heat Safety Should Begin Before the Event

A central message of the new WHO guidance is that organizers should not wait until temperatures reach dangerous levels before responding.

Heat-related risk management should begin during the planning stage and continue throughout the entire event cycle.

WHO describes this as a “whole-of-event” approach, recognizing that heat safety is influenced by much more than medical services alone.

Venue design, transportation, crowd management, water and sanitation systems, security operations, communications and workforce management can all determine whether people are able to access drinking water, cooling areas or timely medical assistance.

Heat planning should therefore form part of broader emergency preparedness and all-hazards risk management for mass gatherings.

Important for Tourism and International Events

The guidance also carries implications for destinations hosting international visitors and large tourism events.

Major festivals, marathons, concerts, sporting competitions and cultural celebrations can attract tens or even hundreds of thousands of people, many of whom may not be accustomed to the destination's climate.

For tourism-dependent destinations, preparing for extreme heat can therefore become part of both visitor safety and destination management.

Measures such as water stations, shaded rest areas, cooling facilities, clear multilingual health information, appropriately scheduled activities and readily accessible medical services can help reduce health risks while supporting a safer visitor experience.

This is particularly relevant for destinations in tropical and subtropical regions, including countries across Southeast Asia, where outdoor festivals, sporting events, religious celebrations and tourism activities frequently take place in hot and humid conditions.

WHO Calls for Heat Risk Management to Become Standard Event Planning

WHO is calling on governments, event organizers and relevant partners worldwide to incorporate heat-risk management into routine planning and operations for mass gatherings.

The new resources are intended to complement existing national heat-health action plans, occupational health and safety requirements, emergency preparedness systems and clinical guidance.

As extreme temperatures become an increasingly important global health challenge, the message from WHO is clear: heat-related illness at major events is not simply something organizers must respond to after people become sick. In many cases, the risk can be anticipated, reduced and managed before an emergency develops.

For governments, tourism destinations and event organizers, preparing for heat may increasingly become as fundamental to event safety as crowd control, security and emergency medical planning.

 

Source :   World Health Organization (WHO)