Intense heat and high humidity could pose a serious risk to athletes at this year's Tokyo Olympics, according to a new report.
The report, published Wednesday by the British Association for Sustainable Sport, details the concerns of leading athletes and scientists about the health impacts of soaring temperatures in Japan.
According to the report, the average annual temperature in Tokyo "has increased by 2.86 degrees Celsius since 1900, more than three times as fast as the world's average."
The Olympics are due to run from July 23 to August 8 -- a time when Japan usually experiences its highest annual temperatures, which are soaring even higher in the warming climate.
"I think we're certainly approaching a danger-zone," Great Britain rower and Olympic hopeful Melissa Wilson told the study's authors. "It's a horrible moment when you see athletes cross the line, their bodies fling back in total exhaustion, and then not rise up."
Some events at the upcoming Summer Games have already been moved away from Tokyo amid heat concerns, including the marathon, which will take place nearly 500 miles north of the Japan capital in Sapporo where temperatures are expected to be much cooler.
The study details how events such as the triathlon, the marathon, tennis and rowing could be adversely impacted by hot conditions.
It also provides advice to athletes on how to cope with competing in the heat, as well as warning how the climate crisis could derail sporting events in the future.
"Olympic organisers must take the warnings in this report seriously or face a real risk of competitors collapsing through heat exhaustion," said Mike Tipton, professor of human and applied physiology at the Extreme Environments Laboratory, School of Sport, Health & Exercise Science at the UK's University of Portsmouth.
"In a sporting context, a hot and/or humid environment can represent a risk to the performance and health of spectators, officials and athletes. From sunburn, through cognitive impairment, to heat exhaustion or collapse from heat stroke, all facets of a sporting event -- and all those involved -- can be adversely affected."
In a statement to CNN, the International Olympic Committee (IOC) said that "athletes' health and well-being are always at the heart of our concerns" and that "a wide range of measures are being taken ... to mitigate the effects of the temperatures which may occur this summer."
These measures include changing the start times of some events -- such as long-distance running, rugby, triathlon and cycling -- and equipping events with shade, water sprays and access to water supplies.
"The IOC takes concerns about heat very seriously," the statement added. "The Olympic Games are the platform where athletes can give 'once-in-a-lifetime' performances, and these measures ensure they have the conditions to give their best."
In recent years, Japan has seen record-breaking temperatures during the summer months as heat waves have become increasingly commonplace. The heat wave of 2018 resulted in more than 1,000 deaths, according to the Japanese government.
"While the average high temperature in Tokyo during the Olympics (late July to early August) is 30-31 C (86-88 F), they frequently experience high temperatures in the mid 30s (mid 90s F) and in recent years have even approached 40 C (104 F)," said CNN meteorologist Taylor Ward.
"Combining this heat with very high humidity has led to several deadly summer heat waves across Japan in recent years. These conditions will no doubt put extreme strain on athletes in outdoor venues during the Olympics," Ward said.
"These recent summer heat waves that have impacted many areas across East Asia (and the globe) can be attributed, in part, to climate change and global warming. As our planet warms due to increasing greenhouse gas emissions, our climate is changing in many ways. One of those ways is increased heat waves -- longer duration, more intense, and greater frequency. Recent scientific studies have attributed more extreme heat waves in Japan to climate change, and notes that they are becoming increasingly likely as the planet warms."
When Tokyo last hosted the Olympics in 1964, it did so in the cooler month of October. But broadcasting demands now stipulate that the Games are held in July or August, according to Reuters -- a more favorable slot for TV networks.
It's not just the Olympics that has to take searing temperatures into consideration.
At the 2019 World Athletics Championships in Doha, Qatar, marathon runners toiled in 32-degree heat and humidity levels above 70%, even after start times were moved to midnight. In the women's event, 28 of the 68 runners who started failed to finish and some had to be stretchered off the course.
At tennis' Australian Open, meanwhile, recent temperatures have been known to exceed 40 degrees Celsius, causing players to faint on the court.
