The number of patients grappling with heat-related illnesses is rising fast as the end of monsoon rain gave way to scorching heat.

According to the Korea Disease Control and Prevention Agency(KDCA), while there were only four such patients last Sunday, the figures spiked to 46 on Wednesday and 62 on Thursday.

The collective term of heat-related illness covers a range of ailments such as heatstroke, heat exhaustion, fainting and heat cramps that occur when people are exposed to high temperatures for an extended period.

The cumulative patient tally between May 20 when a monitoring system was activated and July 27 stands at 868 nationwide including three suspected deaths. 

Of the total, men accounted for over 79 percent at 688. By age, those in their 50s took up the largest portion at 21 percent.

Heat exhaustion, symptoms of which include muscle cramps, vomiting, sweating and fatigue, was the leading cause accounting for 50-point-seven percent of all cases while over 31 percent of patients fell ill at their workplace.

Meanwhile temperatures climbed to over 37 degrees Celsius in many parts of the country on Friday and the Korea Meteorological Administration forecasts the scorcher to continue through the weekend.

The KDCA advises people to refrain from outdoor activities during the hottest hours of noon to 5 p.m. and drink lots of water even if they don't feel thirsty.