A woman holds an umbrella while another uses a portable fan as pedestrians cross an intersection under the sun in Tokyo's Shibuya district on July 9, 2026. (Kyodo)

TOKYO - The risk of death from heatstroke rises when the daytime high exceeds 27.1 C, a joint study by the Tokyo metropolitan government and the University of Tokyo has found, with the research team urging people to actively use their air conditioners as midsummer approaches.

The study by the Tokyo Medical Examiner's Office and the university's graduate school analyzed 1,447 cases in Tokyo's 23 wards where heatstroke was listed as the cause of death between January 2013 and September 2023, examining factors such as weather conditions at the time of death and whether air conditioners had been installed.

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