The Summer Games of 2020 are expected to be hot -- both in temperature and in excitement. With the games set to begin in just under two years, the Mainichi Shimbun asks athletes, coaches and support staff how they plan on competing in the scorching heat.
The temperature has soared above 35 degrees Celsius, and the sun is beating down relentlessly. Hirooki Arai, a member of the Self-Defense Forces who competes in the 50-kilometer men's racewalk, carries ice in his hands as he trains.
"When you hold something cold in your hands, your blood cools down, which then cools down your entire body," he explains.
For Arai, who captured the bronze in the 2016 Summer Olympics in Rio de Janeiro, and a silver medal in the 2017 World Championships in Athletics, icing his hands has been one of his measures for dealing with the heat.
In anticipation of the upcoming 2020 Summer Olympics and Paralympics in Tokyo, the Japan Association of Athletics Federations (JAAF) began incorporating the practice of lowering blood temperatures among racewalkers and marathon runners by cooling the palms of their hands three years ago. Masaaki Sugita, a professor at Nippon Sport Science University and the chairman of the JAAF's Science Committee, explained to athletes at a training camp the efficacy of cooling one's hands to keep body temperatures down, and introduced a hand-cooling device called CoreControl.
Arai was the one who proved how effective the method could be at the Rio Olympics. The outdoor temperature was 22 degrees Celsius when the 50-kilometer racewalk began at 8 a.m., but the sun's rays grew increasingly intense. When Arai came upon water stations in the sweltering heat, he reached for the ice that had been placed there for him to cool his hands. "From the outset, I tried as much as I could to grab ice," he recalled.
As a result, when he and a Canadian rival went head to head at the very last leg of the race, Arai had enough stamina to become the first Japanese racewalker to come away with an Olympic medal. Now, hand-cooling has become common practice among various teams in the summertime. Takayuki Tanii, another member of the Self-Defense Forces who captured the bronze in the 50-kilometer racewalk in the 2015 World Championships in Athletics, emphasizes the method's effects on his body, saying, "I can feel the cooling effect, and it keeps my heart rate from getting too high."
According to Kobe Women's University professor Kozo Hirata, who researches environmental physiology, and the JAAF's Sugita, the palms of hands and the backs of feet have arterio-venous anastomoses (AVAs), which connect arteries with veins. AVAs open up when body temperatures rise and the need for heat to be released from the body arises. AVAs have a diameter approximately 10 times, and transport blood volumes of around 10,000 times that of capillaries, respectively.
Thus, if the palms of hands, which have AVAs, are cooled, large volumes of blood are also cooled and returned back to the body, reducing both body temperature and heart rate. It may not feel as refreshing as dumping water over one's head, but it is much more effective at cooling one's blood, and therefore one's body temperature.
Sugita points out that hand-cooling is not a practice that should be set aside only for the day of competitions, since it is something that can be done before, during and after training. "It's meaningless if it's used only as a heat countermeasure at competitions," Sugita says. "What's important is whether athletes (can effectively cool down their bodies) and continue quality training during the hot summer season."
Tadasu Kawano, the JAAF's long distance and marathon development project director, points out, "When athletes use CoreControl after a 40-kilometer run, their body temperature drops, and they're able to regain their appetite and recover quickly in other ways as well."
Arai says he is always looking for more effective ways to cool the palms of his hands. "Measures against the heat will be crucial in the Tokyo Olympics. What may seem like slight ingenuity can make a huge difference," he says.
(This is Part 1 of a series)
(Japanese original by Ryuichi Arai, Osaka Sports News Department)