Yesterday was hot. The temperature reached 34 degrees Celsius (93 F) in Kumamoto City and 18 people were treated for heatstroke:

http://kumanichi.com/news/local/main/20150709003.xhtml

Today and tomorrow are also predicted to be quite hot, though the temperatures should be slightly lower than yesterday.

The July issue of Kumamoto City’s Shisei Dayori (City Info) includes some information about what to do if someone seems to be suffering from heatstroke:

http://www.kumamoto-if.or.jp/topics/topics_detail.asp?PageID=5&ID=7912&pg=1&sort=0&LC=e

And here’s some advice about avoiding heatstroke:

http://www.mayoclinic.org/diseases-conditions/heat-stroke/basics/prevention/con-20032814