Climate MattersJuly 21, 2021

Climate Change & the Olympics: Competing with Heat

Climate Change & the Olympics: Competing with Heat


  • Japan’s climate is warming due to climate change. And the added heat, on top of an already hot and muggy summertime climate, could make the 2021 Tokyo Olympics and Paralympics one of the hottest in modern times.

  • Even the best athletes will be adversely affected by climate change. More intense heat, humidity, and poorer air quality could lead to heat-related illnesses and decreased performance. 

  • In hotter temperatures, certain sports, like the marathon, tennis, and the triathlon, can become dangerous. Factors that can increase heat risk include duration of play, intensity of play, surface of play (water vs. turf vs. blacktop), and more.

  • To get ahead of the heat, Olympic organizers have changed the location of events, set up cooling stations around venues, and encouraged athletes to incorporate “cooling downs” before, during, and after their event.

Heat Illness Infographic - Climate Change & the Olympics: Competing with Heat
Heat Illness Infographic
Tokyo Very Hot Days - Climate Change & the Olympics: Competing with Heat
Tokyo Very Hot Days
Tokyo Average Temperature - Climate Change & the Olympics: Competing with Heat
Tokyo Average Temperature


The NEW IPCC report (Sixth Assessment Report - Working Group I - The Physical Science Basis) is expected to be released on Monday, August 9. An online press conference to present the Summary for Policymakers will be held in concert with the release at 4am ET on August 9. Registration is required. You can also request an embargoed copy of the Summary for Policymakers, but you must register in advance.

More information and RegistrationRequest an interview with the authors

Can we be “Faster, Higher, Stronger” in a warming world? The motto of the Olympics “Citius (Faster), Altius (Higher), Fortius (Stronger)” has rung true for millennia. However, as the world warms due to climate change, our extraordinary human talents may be approaching their limits with more intense heat and worsening air quality. 

State of the Climate: Japan and Tokyo heat: Japan’s climate is becoming warmer due to climate change. And the added heat, on top of an already hot and muggy summertime climate, could make the 2020 Tokyo Olympics and Paralympics one of the hottest in modern times. The event will span the hottest months of Japan—triggering concerns about heat risks for competing athletes:

  • In Tokyo, July and August average temperatures have warmed by 2.7°F since the last time the Olympics were held there in 1964.

  • The number of days above 95°F (35°C) in Tokyo has increased by 8 days since 1964. Last year, there were 12 days above 95°F.

  • In 2018, a heatwave in Japan resulted in 22,000 hospitalizations and over 1,000 deaths. Scientists recently determined that this heat event would not have happened without the influence of climate change.

How can heat affect the world’s best athletes? Heat is a nuisance to outdoor athletes, but with climate change rising temperatures, it can quickly become the enemy. The body functions at a stable 98°F, but hotter temperatures—paired with physical activity—can easily result in overheating. With conditions becoming hotter in Japan, athletes could be at risk of heat-related illnesses.

  • Athletes are specifically at risk of exertional heat stroke. It occurs when the body overheats during physical activity. Without proper cooling interventions, it can be fatal. 

  • Some Paralympic athletes face additional challenges regarding the heat. For instance, athletes with a spinal cord injury may have trouble thermoregulating where they are impaired.

  • Air Quality: Intense heat can also impact the ability to breathe. Intense heat creates ground-level ozone and traps harmful pollutants at the Earth’s surface that can inflame an athlete's airways, resulting in coughing, wheezing, and shortness of breath.

A breakdown of heat risk by sporting event: Some outdoor sports are affected by heat more than others. Duration, intensity, and even the playing surface of the sport can increase heat risks.SportHeat Illness RiskRisk FactorsArcheryLow/MediumDuration of exposure to extreme conditionsTennisHighDuration of match with added high physicalityHockeyHighDuration of game and limited opportunity for recoveryGolfMediumPlay often unfolding during hottest hoursBaseballMediumDuration of exposure to extreme conditionsCanoeingMediumReflected radiation from waterSailingMediumShade-free exposure to extreme conditions, including during race build-up, and reflected radiationRugbyMediumMultiple games in a dayFootballMediumHigh physicalityTriathlonHighRaised water temperaturesMarathonHighIncreased road surface temperatures

Table: “Contributory Factors That Can Increase Health Risk Around Heat & Select Sports” from the British Association of Sustainable Sport "Rings of Fire" report.

Attempts to cool the heat: Event coordinators, athletes, and trainers have already implemented solutions to cool down the Olympics and Paralympics. Some solutions include:

  • Change in location: Olympic officials, with the guidance of concerned doctors, relocated the marathon to Sapporo, Japan (over 500 miles north of Tokyo) to avoid the heat.

  • Cooling Stations: The International Olympic Committee (IOC) launched the “Tokyo 2020 Cooling Project” to set up mist sprays, water stations, and shaded areas for athletes and spectators. 

  • Acclimatization: Many teams, like Canada’s track and field team, are training for several weeks in locations with a similar climate to Japan to help acclimate to the heat and humidity.

  • Pre- and Post-cooling: Cooling interventions (cold water immersion, drinking cold water, etc.) before, during, and after events can greatly reduce the risk of exertional heat stroke.

What is the fate of future Olympic Games? With global temperatures continuing to rise, future Olympic Games may face serious problems with air quality and intense heat. As long as greenhouse gases are pumped into our atmosphere, the world’s best athletes—and humans in general—will experience conditions that impact our performance and health. In efforts to improve future Olympics, the IOC has taken steps to combat climate change. This includes a renewed sustainability agenda and promises to run 100% on renewable energy.


A list of organizations that investigate the impacts of climate change on sports:


The SciLine service, 500 Women Scientists or the press offices of local universities may be able to connect you with local scientists who have expertise on sports and climate change. The American Association of State Climatologists is a professional scientific organization composed of all 50 state climatologists. Or contact the Korey Stringer Institute to speak with “ambassadors” from around the country who have personal stories regarding heat exertional illness.

To search or gather more information on a specific Olympian, you can scroll through the official website for Team USA here:


  • Jennifer Vanos, PhD
    Assistant Professor, School of Sustainability, Arizona State University

  • Yuri Hosokawa, PhD, ATC
    Associate Professor, Faculty of Sport Sciences, Waseda University

  • Rebecca M. Lopez, PhD, ATC, CSCS, ACSM-EP
    Associate Professor and Director, Advanced Athletic Training, University of South Florida
    Contact:*Available for interviews in English and Spanish


All data was sourced from the Japan Meteorological Agency.

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