Hospitals are stretched to their limits during unseasonably early heatwave, as medical authorities liken public health risk to a ‘natural disaster’

Medical experts in Japan are to add a “most severe” category to the current heatstroke index, amid warnings that the extreme heat is straining medical services and causing damage to public health comparable to that in a “natural disaster”.

The Japanese Association for Acute Medicine said it would add a fourth category to the three-level classification later this year in an attempt to reduce deaths from heatstroke.