One runner was in critical condition on Sunday after tens of thousands braved steamy conditions and pollution warnings to take part in the annual Hong Kong marathon.
"There is one male patient whose condition is critical," a Hospital Authority spokeswoman told AFP. Five other patients were in a stable or satisfactory condition, she said.
Organising committee chairman William Ko earlier said the male runner was "considered rather serious" but did not have further details. Thirty-four people needed hospital treatment, he added. A 53-year-old man collapsed and died and about 5,000 needed medical treatment during last year's race, which took place in high levels of pollution.
Ko hit back at one leading expert who warned athletes were risking serious heart problems by running in Hong Kong's notorious smog. "That to me was a negative approach," he said. "Our positive approach is very simple - we advised to have better training and better preparation for the race.
"This year the situation was miles better than last year." Pollution levels hovered at medium to high according to Hong Kong's air pollution index, which green groups have criticised for being out of date.
Relative humidity reached 95 percent in temperatures of about 25 degrees Celsius (77 degrees Fahrenheit). A record 43,956 runners entered the 10km, half-marathon and marathon events. Kenyan athletes finished first, second and third in both the men's and women's marathons.