She had participated in six marathons, had a taekwondo black belt and led an active life.
But she collapsed 150m from the finishing point of the Nike We Run 10km event on Sunday.
Ms Wu Kai Ling, 25, was pronounced dead at the Singapore General Hospital that day.
She had collapsed around noon, near Raffles Boulevard.
Lianhe Wanbao reported that she was an engineer with ST Electronics.
A Nike spokesman told the Chinese evening daily that after Ms Wu collapsed, medical personnel administered first aid before she was sent to the hospital.
Her death shocked her family.
Ms Wu's grandaunt said: "My grandniece would exercise often and has participated in six marathons."
She added that her grandniece was always healthy, but had complained about having a flu a few days before the run.
Ms Wu was a taekwondo black belt holder and had practised the martial art for 14 years.
Her taekwondo coach, who attended the wake with 10 other students told Wanbao:
"She was an exceptional martial artist and she was very serious about taekwondo. "She attended every training without fail for 14 years."
The taekwondo coach also said that Ms Wu completed last year's Standard Chartered 21km Half Marathon.
An estimated 20,000 runners took part in the Nike We Run event.
US sprinter and four-time Olympic champion Allyson Felix was there to flag the runners off.
Police confirmed that they were notified of the death on Sunday at about 12.30pm and have classified it as an unnatural death.
Investigations are ongoing.
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