When the heat makes its way into the sporting calendar [1/2]

It wasn't long ago that temperature started appearing as a critical seasonal factor on sports calendars. Training sessions were moved to the early hours of the day, breaks were adjusted, and athletes were advised to drink more water. The issue seemed to be a matter of common sense rather than strategy.

The increasing frequency of extreme heat waves is gradually changing the landscape. From Europe to South Asia, from Africa to North America, competitions are facing temperatures that complicate, or even make dangerous, physical activity. Heat waves are a global phenomenon. They affect territories with very different climates and levels of development, even if their manifestations and consequences vary considerably from one region to another.

Europe offers a particularly significant example. It is currently the fastest-warming continent. The European State of the Climate 2025 report , published jointly by Copernicus and the World Meteorological Organisation, indicates that the continent has been warming since the 1980s at a rate approximately twice the global average. By 2025, heat waves had already affected regions stretching from the Mediterranean to the Arctic.

For a sporting movement accustomed to organising its seasons according to relatively predictable schedules, this development introduces a variable that has become difficult to ignore.

Humans struggle to dissipate our own heat

The issue is primarily physiological. When the body exerts itself, it produces heat. To maintain its internal temperature, it increases blood flow to the skin and triggers sweating. However, as temperature and humidity rise, the body's ability to dissipate this heat gradually becomes less efficient.

The International Olympic Committee's consensus statement on sports practice in heat reminds us that this thermal stress can affect both health and performance. Experts recommend, in particular, assessing environmental conditions, planning hydration and cooling strategies, and adapting competition organisation when conditions require it.

Dehydration and fatigue are the first signs. In the most severe cases, heat exhaustion and then heatstroke can occur, a medical emergency that can lead to neurological damage and be life-threatening. The World Health Organisation reminds us that the health effects of heat are expected to worsen with climate change and that exposure to extreme temperatures is increasing in all regions of the world.

Performance also suffers. The body must dedicate an increasing share of its resources to cooling itself, at the expense of muscular effort. Heat is therefore not only a danger: it alters the conditions under which an athlete can utilise their abilities.

Elite athletes are starting to rethink their habits

Major competitions have gradually incorporated this reality. Schedules are sometimes moved forward or back to avoid the hottest periods. Medical protocols are strengthened. Teams work on athlete acclimatisation, hydration strategies, and cooling techniques before, during, and after exertion.

The IOC consensus recommends, in particular, monitoring thermal conditions before and during competitions and implementing measures to reduce the heat load experienced by athletes. However, these solutions are easier to implement in professional sport. Both an athlete supported by a doctor or physiotherapist and staff members capable of adapting their training program do not face the same constraints as a recreational athlete who has access to an hour of municipal sports field per week.

This difference is crucial. Because exposure to heat doesn't depend solely on the thermometer. It also depends on the conditions under which the sport is practised.

A new responsibility for those involved in sport

Prevention must now take centre stage. Coaches, educators, referees and volunteers must be able to spot the first signs of poor heat tolerance and have sufficiently clear protocols to interrupt or modify an activity.

This need extends beyond elite sports alone. In Europe, the WHO has observed that, over the past thirty years, periods during which heat poses a risk to physical activity have expanded beyond the traditionally hottest hours of the day. The organisation believes this trend could contribute to a decrease in physical activity, with potential consequences for non-communicable diseases.

This also implies abandoning a certain culture of pushing oneself to the limit. In sports, the ability to endure pain or discomfort has long been valued. But extreme heat is not an additional challenge to be learned and overcome. It constitutes a physiological stress that can endanger the body.

Climate change is thus forcing a shift in perspective for sport. It's no longer simply a question of how to continue playing, running, or cycling when temperatures soar. We must determine under what conditions these activities can remain compatible with health.

And behind this question, the following is already emerging: in a warmer world, will all practitioners have the same means to adapt?

Read part 2 of this article