At least two deaths have been linked to the heat wave that has gripped South Korea over the last few days, health authorities confirmed Tuesday.

As of Tuesday afternoon, heat wave warnings have been issued in most regions across the country, including Seoul, South Jeolla and South Gyeongsang provinces. Daytime highs reached 35 degrees Celsius in most provinces nationwide.

The “tropical night” phenomenon -- defined by nighttime low temperatures staying above 25 degree Celsius -- has prevailed in many regions, including Gangneung in Gangwon Province, Daegu and Uljin, North Gyeongsang Province. 

According to the Korea Centers for Disease Control and Prevention, a total of 285 Koreans were treated for heat-related illnesses from Thursday to Sunday. They accounted for 52 percent of all Koreans who sought medical treatment in the same time period.

Among the 285 patients who have been treated for heat-related conditions, two have lost their lives. Prior to Thursday, two other Koreans died of heat-related causes this year.

Both of the two victims, who died on Thursday and Sunday, respectively, were female and in their 80s, and became ill after working at their own outdoor farms in South Gyeongsang Province.

At the same time, some 790,000 livestock animals across the nation have died from heat stress. Together they have caused damage worth 4.2 billion won ($3.7 million), according to the government. The largest number of animals killed by the heat were chickens, followed by ducks and pigs.

Some schools in Gyeonggi Province have shortened school hours due to the weather.

From 2013-2017, some 6,500 Koreans were medically treated for heat-related illnesses. Among them, 40 percent became ill after spending time at outdoor spaces, such as construction sites and farms, between noon to 5 p.m.

To avoid heat-related illnesses, the KCDC advised drinking plenty of fluids and wearing loose-fitting, lightweight clothing. When one cannot avoid staying outdoors in the hot weather, it is important to rest frequently in a cool spot and to stay hydrated at all times, the agency added.

Health authorities also stressed that heatstroke is a serious medical emergency and can be life-threatening.

People with underlying health conditions, such as lung conditions, mental illness or heart disease, as well as those who live in accommodations without air conditioning, and elderly individuals who live alone, are some of the most vulnerable, the health authorities added.

“If you see someone who has lost consciousness after being outdoors in hot weather, make sure you call 119 -- the Korean version of 911 -- and seek emergency and professional help, the KCDC said in a statement.

The Korea Meteorological Administration said the heat will continue for at least 10 days.

By Claire Lee (dyc@heraldcorp.com)