Extreme heat, its impact on sport, and solutions for venue design

Sport is an important part of human society, providing us with entertainment and health benefits, opportunities to create relationships, and a sense of belonging to a particular community. Playing sport and being active, at whatever level, is fundamental to both our physical and mental wellbeing. However, high temperatures limit when we can play and consume sport and increasingly frequent and intense heatwaves are changing how we design sporting venues.

Sport at all levels is impacted by increasing global temperatures, changing the way professional athletes and amateurs train, when they compete and how sports facilities are designed. A recent report by the Institution of Mechanical Engineers¹ stated that the global sports industry is responsible for around 1% of global carbon emissions. This means that sport is another example of an industry which needs to adapt to climate change without resorting to energy intensive, greenhouse gas emitting, solutions.

Physical Impacts

The summer Olympic Games, where over 30 sports are played, is considered the world’s foremost event for elite sport. A report² published by The British Associated for Sustainable Sport (BASIS) ahead of the 2024 Paris Olympics looked at the heat risks for athletes at the Games. The report includes testimonies from athletes across a range of sports, reflecting on their experience of the 2020 games hosted by Tokyo (reported to be the hottest on record³) and other summer tournaments. Experiences included a tennis player who left the court in a wheelchair due to heat exhaustion, an athlete who suffered from vomiting, blurred vision and muscular fatigue and a competitor who reported concerns about the long-term impact of heat stress on their body. Rower Jenny Casson, spoke of training within a heat chamber to prepare her body for competing in high temperatures.

In the foreword to the report, Lord Seb Coe, president of World Athletics, warns that “with global temperatures continuing to rise, climate change should increasingly be viewed as an existential threat to sport”.

The human body has a range of sophisticated physical mechanisms which allow it to adapt to, and function in a variety of thermal environments. However, exercising in extreme heat increases the body’s core temperature and excessive humidity prevents the body from regulating this heat load through sweating. For this reason, most sport governing bodies have criteria which limit play in extreme climate conditions. To monitor these conditions, measurements of Wet Bulb Globe Temperature (WBGT) are taken using a handheld device and, where conditions present a risk to heat stress, additional cooling breaks are introduced, or play is stopped. Even when conditions don’t present a risk to health, environments with high temperature and humidity result in a decline in athletic performance, which leads to fewer world records being broken, slower games in team sports and, in some cases, risk of injury due to poor cognitive decisions.

The impact of extreme heat in athlete accommodation also plays a key role on performance, impacting sleep quality and speed of recovery from exercise. At major events, athlete housing is often air conditioned to maintain cool conditions, particularly in hotter climates. However, the 2024 Olympic games in Paris made a bold decision not to air condition its Olympic Village as a part of their overall commitment to reduce energy use, opting instead to use a geothermal water system to keep buildings cool. However, several nations (including reportedly the French team) opted to install mobile air conditioning units to ensure athlete comfort and, therefore, peak athletic performance⁴. This highlights the increasing tension between the sustainability goals for major events and the need to provide environments to allow athletes to achieve peak performance. All eyes now look to Los Angeles for how they address this in 2028.

Adapting to how we deliver sporting events and design venues

A recent study in Nature⁵ focusing on the Olympic Marathon reported that when climate projections through to the end of the century are considered, the number of possible global cities that can host the summer Olympics will decline by up to 27%. The paper goes on to note that shifting the event to October would be an effective mitigation measure. The 2022 Football World Cup, hosted in Qatar, was shifted to a winter tournament to avoid the extreme summer heat and the Tour de France is considering moving away from a July event (breaking over 100 years of tradition) following heat-related illnesses in 2024⁶. However, seasonal shifting of events can be disruptive, most notably the 2022 Football World Cup required the European leagues to introduce a six week break in their winter fixture schedule.

Event start times may also be adjusted to cooler times in the day. During the Tokyo Olympics the start time for the Marathon Swim was brought forward to 6.30am, however this required wake up times of 3am for athletes⁷ to allow them to prepare for the event. Event scheduling is also driven by a desire from spectators and broadcast viewers to consume sport live. Starting an event at an antisocial time can reduce the broadcast viewers which has a not inconsiderable knock-on impact on advertising revenue.

High temperatures don’t just affect athletes, they also impact spectators and officials. This was seen during the Football World Cup in Brazil in 2014 where significant numbers of spectators left their seats when exposed to high temperatures combined with direct sun⁸. Play was also stopped during Wimbledon in 2017 when a women in the crowd collapsed due to heat issues⁹. Organisers of major events must plan for the safety of spectators and officials in high temperatures, by considering how people travel to an event, time spent queueing and the location of key staff with respect to provision of shade and access to water. The provision of shade for spectators is shifting from temporary structures that are erected on event days, to permanent shading structures which are a fundamental component of the architectural vision for newly constructed sports venues. An example is the new SoFi stadium in Los Angeles, which features an extensive roof canopy covering a 2.5-acre spectator plaza¹⁰.

Community sports facilities

Moving away from elite sport, the general population typically plays sport for social reasons, or to maintain their physical and mental health. Venues for these ‘grassroots’ sports activities range from purpose-built sports halls and stadia, through to venues woven into our urban fabric such as public parks, as well as the local outside environment for simply running in the neighbourhood. Sport specific venues for grassroots use often incorporate air conditioning to maintain acceptable playing conditions, however, the equipment within these venues is traditionally designed based on historic climate data thereby creating a potential need to close the venue during a climate change induced extreme heatwave event. Many global cities were designed for cooler climates and the urban heat island effect increases temperatures and prolongs heat wave events, which affects those who train outdoors. For this reason, cities such as London¹¹, are looking to plant more trees to create shade and to combat the urban heat island effect. The impact of heatwaves on physical activity is a concern for government bodies, such as Sport England, which reported that one in seven adults and a quarter of children, felt that the weather was unsuitable for activity during the 2022 heatwave¹².

Getting the balance right

Sport at all levels is impacted by increasing global temperatures, changing the way that we train, when we compete and how we design sports venues. As someone who works in venue design from grassroots through to elite stadia, my clients routinely ask for venue designs which are sustainable, resilient to a changing climate and have an incredible environment for players and spectators. In terms of cooling provision, the key is to get the balance right between meeting the comfort and health needs of participants and spectators alike, whilst delivering solutions that result in zero, or minimum possible, greenhouse gas emissions, air quality degradation, water consumption, and other environmental impacts.