When it comes to heatstroke, the scorching summer of 2010 takes the cake.

As record heat waves swept the globe, Japan saw 28,020 heatstroke victims taken to hospitals in ambulances from the end of May to Aug. 8, with 118 of them dying, the Fire and Disaster Management Agency said.

Following are questions and answers regarding heatstroke and its symptoms:

What causes heatstroke?

Heatstroke is a condition brought on by exposure to high heat and a failure to regulate body temperature, in many cases due to dehydration.

A failure to rehydrate leads the blood to concentrate and upsets circulation.

Heatstroke symptoms can be subtle at first, including drowsiness that may actually precede the loss of consciousness, slow motor responses and slurred speech.

According to the Environment Ministry, 6,770 people died of heatstroke nationwide over a 40-year period up to 2007.

Most of the fatalities were those aged 65 or older — 54 percent of the annual figure in 1995, 69 percent in 2004 and 74.9 percent in 2007.

Heatstroke can strike at night as well. According to the Tokyo Metropolitan Government, at least 24 of the 96 heatstroke deaths since July 17 occurred during the night.

Why has heatstroke grabbed attention in recent years?

Several stories in the news media have focused on the number of young people coming down with heatstroke after failing to drink enough water during outdoors sports activities.

In many cases, it is later revealed they were given misguided information about the role that hydration plays during physical exercise.

Teenagers had long been educated not to drink water during exercise due to the mistaken belief that hydration brings on exhaustion and causes even more perspiration.

This notion stems from a book written by sports educator Chiyosaburo Takeda in 1904 that claimed the way to build a strong body was to minimize hydration, according to Yoshiteru Muto, a professor at the University of Tokyo’s graduate school of education.

“That theory spread widely, causing a century of misunderstanding in education that we shouldn’t drink water during sports,” Muto said.

According to Otsuka Pharmaceutical Co., which produces the sports drink Pocari Sweat, 203 people died of heatstroke while engaging in sports between 1970 and 2005.

They included 65 who died while playing baseball, 29 who were engaged in mountain climbing and 26 running in marathons. Most were male and ranged in age between 13 and their early 20s.

What’s the best way to ward off heatstroke?

Experts stress the importance of drinking water, avoiding the sun during the hottest parts of the day, generally between 10 a.m. and 2 p.m., using fans or air conditioners and placing a bag of ice or cold gel on the neck.

Saline drinks are also helpful because the body loses vital salt during perspiration. In recent years, salt candies have been popular with those who have to hard work under the sun.

Athletes should aim to rehydrate 70 percent to 80 percent of what they lose through perspiration. In high temperatures, they should take frequent breaks and consume 200 to 250 milliliters of liquid two to four times an hour, the Japan Sports Association says.

If engaged in heavy physical activity, drinks containing sugar can also be helpful.

Is the government doing anything to correct misunderstandings about heatstroke?

The Health, Labor and Welfare Ministry launched a campaign in 2008 to promote the importance of drinking water.

One of three campaign posters bears large characters reading: “I’m thirsty. Teacher, let me drink water.”

The poster explains these were the last words of a student who died after running during a summer club activity who was denied water as part of disciplining.

“The campaign was launched partly because cases of hyperthermia were continuing and Japanese continued to not drink enough water,” ministry official Naoko Moritani said. “The campaign is also meant to give teachers the proper understanding that we need to drink water during sports.”

What actions are recommended if someone encounters an apparent heatstroke victim?

Besides summoning professional help, bringing down a victim’s body temperature should be the first course of action, according to a recent report on hyperthermia by the Environment Ministry.

Victims should be taken to a place where air is circulating, or better yet, into an air-conditioned environment.

Other steps include dousing the victim with water, loosening clothing that may be hot or restricts proper breathing, and placing bags of ice on the neck, under the arms and near the groin, the report says.

The Weekly FYI appears Tuesdays (Wednesday in some areas). Readers are encouraged to send ideas, questions and opinions to National News Desk