Organizers are concerned about the steamy conditions in Tokyo, especially after 28 of 68 starters failed to finish the women's marathon and 18 of 73 men didn't complete the course in Doha. Those races were run at midnight, with the women's event starting at 32.7 degrees C (91 degrees F).
Ethiopian runner Lelisa Desisa won that men's race, but he said Thursday the conditions were "dangerous" and that the sport's governing bodies — worlds are organized by the International Association of Athletics Federation — can't put runners in that position again.
"We are human, you know?" he said. Temperatures in Japan don't project quite so high, but either Tokyo or Sapporo would likely present unusual marathon conditions. Estimates suggest the temperature in Tokyo for a 5 a.m. start would be 27 degrees C (81 degrees F), compared to 25.4 degrees C (78 degrees F) in Sapporo for a 7 a.m. start.
Runners preparing for this weekend's New York City Marathon were unanimous Thursday on just one front: they're pleased the IOC is considering the health and safety of the athletes. "I think with Doha, they got a bit of a reality check in how bad it can go," said Australian runner Sinead Diver.
"It's not just like, 'We want it here. We want it at this time. Blah, blah blah,'" added American Olympic hopeful Kellyn Taylor. "They're taking into account the things that happened in Doha and really trying to make it better."
The pack breaks from there, for varying reasons. For starters, racers are eager to run in Tokyo. They want to be near Olympic festivities like the athlete's village and opening ceremonies, and that could get complicated if runners must travel over 1,100 kilometers (nearly 700 miles) north to Sapporo for race day.
Perhaps most critically to the athletes, the Tokyo course was set to finish inside the Olympic stadium — a long-standing tradition cherished by racers that was eschewed for London in 2012 and Rio in 2016.
"Visualizing running into the stadium, having that moment of silence where you go through a tunnel and then you get in the stadium and people are going nuts, it's a really cool picture to think about," said American runner Desiree Linden, who competed in the past two Olympic women's marathons. "It's certainly motivating."
There are also some viewing the heat as not a challenge, but an opportunity. The men's marathon at Rio started at 24 degrees C (75 degrees F) in a sticky rain — warmer and muggier than ideal racing conditions. American marathoner Jared Ward said that climate contributed to his surprising sixth-place finish.
"I feel like I really was able to take advantage of an opportunity in Rio to finish higher than I should have finished in that race," Ward said. "I was not the sixth best marathoner in the world." "It can completely open up the door for people who wouldn't typically be your so-called favorites," echoed U.S. runner Shalane Flanagan, who finished sixth in the Rio women's marathon and retired earlier this month. "It's not necessarily a true test of athleticism quite as much as who calculates the best."
And then there are racers wondering if all this debate is even worthwhile. "If it's not guaranteed to be 10, 15 degrees cooler," Diver said, "I think I prefer to have it in Tokyo." "Everybody's running the same race," Taylor said. "You prepare for it. You run smart. Whatever they're going to do is fine."
The IOC's proposal was delivered suddenly two weeks ago. Koike, among Japan's most powerful politicians, has seized the issue to rally public opinion by criticizing the IOC for moving so quickly and unilaterally, especially after Japan took steps like providing shade for runners and spectators and coating pavement with heat-resistant material. The IOC and Tokyo differ on estimates for temperatures in Sapporo and Tokyo — the IOC claims Sapporo will be cooler by 5 to 6 degrees C (9-11 F), but Tokyo maintains the difference is half that.
No matter where they put the starting line, runners are figuring it will be among the warmest marathons they've run. "It is a Summer Olympics," Linden said. "Anybody who is super surprised that it's hot, I don't know what to say."
As Taylor put it: "It's going to be a suffer-fest."
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