WHO: Mass activities in high temperatures endanger health

The World Health Organization has raised concern that illnesses and health problems caused by high temperatures at mass gatherings, such as major sporting, religious and cultural events, have become a significant risk to public health and to the smooth running of activities.

Experts say those at risk are spectators, participants, volunteers and staff.

A new review of the scientific evidence, covering studies published from 1980 to 2025, documented around 500,000 medical contacts at mass-attendance events, among them more than 22,000 cases of heat-related illness.

The studies also show that, when on-site medical services are well organised, over 90% of patients can be treated there.

Based on these facts, the WHO stresses that extreme temperatures should not be considered only an environmental problem, but also an essential issue of event organisation, safety and management.

Mass events can endanger health for several reasons, starting with prolonged stays outdoors and in the sun, large crowd density, a lack of safe water, travel fatigue, unfamiliarity with the local climate and the additional strain on health services.

To prevent this phenomenon, the WHO recommends an integrated approach across the whole cycle of an event, from the design of spaces, crowd management, water supply and sanitation, transport, security, communication and the protection of staff. In this way, organisers can reduce heat-related illness and deaths, while at the same time avoiding unnecessary strain on hospitals and ambulances.