In a Summer Marathon, Even World-Class Athletes' Lives Are at Risk from Heat StrokeIn order to prevent incidences of heat stroke among athletes and spectators alike at the 2020 Tokyo Olympic and Paralympic Games, work is progressing at a fevered pitch to develop countermeasures against the heat in the stadium environs and along the marathon course. Local municipal governments are focusing their efforts on increasing the number of large trees along the course to improve shade, and on implementing road surface materials with heat shielding properties. In past Olympics and World Championships there have been cases of athletes suffering from dehydration and heat stroke, and the issue represents a major challenge for the Tokyo Games.
Late July on Sotobori Avenue in Tokyo's Kanda neighborhood. Under the peak strength of the summer sun helmeted workers hoisted by cranes cut back the branches and leaves of trees lining the street by hand. It looks like ordinary pruning work, but it is actually a part of the new countermeasures against heat introduced by the city government in July. The goal is to reduce the amount of sunlight hitting the pavement by significantly increasing the coverage provided by large trees in the city center. In 2016 the city researched the condition of tree coverage along 45 km of Tokyo streets including the marathon course and the Tokyo Bay area where many venues will be located. About 2000 trees, roughly 70% of the total, were selected as targets for pruning.
Tree branches are normally pruned to a short length, but this time they were given more length in order to encourage growth of longer branches. The suzukakenoki trees along Yasukuni Street in Tokyo's Chiyoda district are currently maintained at a width of 2.7 m and height of 8.6 m, but plans call for them to be grown to 6.5 m in width and 12 m in height over the next three years. According to tests performed by the national government, road surface temperatures are about 7˚C lower in shaded areas than when exposed to direct sunlight. Metropolitan Parks Department Greenery Planning Division director Chiaki Negoro commented, "I would like to see these measures continue after the Olympics so that we can create an environment where pedestrians can stay cool."
Improvements to the roadways making up the marathon course are also underway. In readings taken midday in Tokyo's Nihonbashi area in the summer of 2016, road surface temperatures as high as 60˚C were recorded. For that reason, municipalities within the city and the Bay area have begun painting the easily-heated asphalt with a thermally insulating resin which reflects solar heat. The treatment is said to reduce road surface temperatures by up to 8˚C. Beginning this fiscal year, the Ministry of Land, Infrastructure, Transport and Tourism has also launched a cooperative public and private sector project to plant "green walls," banks of plants grown on city walls. The effects on ambient temperatures of temporary green walls that can be easily installed in the city center are being studied.
The Tokyo Olympics will be held from late July through early August. Although the Paralympic Games will be held a month later from late August to early September, hot temperatures are still a concern. Professor Teruo Doi of the Tokyo Institute of Technology's Environment Transportation Engineering faculty observed, "Because the roads within Tokyo are lined by tall buildings the combination of exhaust from air conditioners and automobiles makes it easy for temperatures to rise. During the Olympics there will be many foreigners here who are not used to Japan's heat and humidity. I would like to see the municipal governments take stronger measures so that they can safely enjoy competing and spectating."
In past summer Olympics and World Championships situations have arisen in which athletes could not perform up to their ability or even had to drop out of their races due to dehydration or heat stroke. In the 1984 Los Angeles Olympics women's marathon, Switzerland's Gabriela Andersen reached the finish line despite staggering from the effects of dehydration. Much of the crowd cheered her on not to give up until she made it, but heat stroke does create a risk of death. Of the 85 men who participated in the marathon in temperatures of 33˚C at the 2007 Osaka World Championships, 28, roughly one-third, dropped out partway.
Yamanashi Gakuin University assistant coach Satoshi Osaki, 41, who represented Japan in that race, recalled, "There was absolutely no shade on the course, and the entire time we were being bathed in both direct sunlight and reflection from the pavement. I was sweating so much that it felt like I was burning up and disintegrating from the inside." Osaki warned that a similar situation could occur at the Tokyo Olympics. "It is absolutely necessary that the start time be set in the early morning or at night," he said firmly. "It is critical for athletes to have constant access to fluid supplies and water they can apply to their bodies. These and other measures are indispensable."
translated by Brett Larner