Almost 1,500 people were transported to hospitals by ambulance due to heatstroke last week, up sharply from 942 in the preceding week, the Fire and Disaster Management Agency said Tuesday.
The increase for the seven days to Sunday came amid a heat wave in western Japan. Toyonaka, Osaka Prefecture, saw the temperature rise to 37.9 degrees on Thursday, the hottest anywhere in the country this year.
The Internal Affairs and Communications Ministry and the Meteorological Agency have been warning people to watch out for heatstroke because temperatures could be high even before the summer starts in earnest.
Osaka saw 194 people sent to hospitals by ambulance for heatstroke last week, the most for any prefecture, followed by 120 each in Hyogo and Aichi.
Of the nationwide total of 1,488 people hospitalized, four died and 31 had severe symptoms that will require at least three weeks of treatment.
Meanwhile, 962, or 64.7 percent, were diagnosed with mild symptoms.
People aged 65 or over accounted for 701, or 47.1 percent, of the total.