A runner died from a heart attack as 22,000 took part in the Brooklyn Half-Marathon in sweltering conditions.
A further 15 people needed hospital treatment as the humidity reached 83% - unseasonably warm for this time of year.
The New York Post reports that the man collapsed and died yesterday morning shortly after finishing the gruelling 13 mile race.
He has not yet been identified.
It's thought the man possibly suffered a cardiac arrest at roughly 9am and was taken to Coney Island Hospital where he was pronounced dead, according to the the New York City Police Department (NYPD).
The runner was reported to have collapsed after finishing the race, according to the New York Road Runners club (NYRR) which held the event. The runner fell on the boardwalk, a source said.
The race, which took the 22,000 runners from the Brooklyn Museum through Prospect Park to the Coney Island boardwalk, was held under unseasonably warm conditions.
The temperature at 9am at Coney Island was already 21C (70F) with 83 per cent humidity, according to Fox Weather.
One police officer said four other people collapsed near the end. "Maybe an organiser or health official should have called it,” the cop said.
A participant also died at the race in 2014.
“The health and safety of our runners, volunteers, partners, and staff remain the top priority for NYRR. In coordination and consultation with the city agency partners and weather experts, NYRR was closely monitoring weather conditions leading up to and during the race,” the group said in a statement.
John Peterson, 26, said he had run the Brooklyn Half Marathon multiple times, but Saturday’s was the hottest and most gruelling one he had experienced.
“You have to be aware of your own body’s limits. Sometimes you wanna go for it and push yourself,” he said.
"And it’s awful sometimes you push yourself too far and this kind of thing happens.”
Anamaria Flores, 42, of Howard Beach said the race was exhausting and she had to walk the final leg. “It was brutal,” she said.
New York Road Runners said it had “medical staff placed from start to finish throughout the race course, who are ready to respond immediately to the medical needs of all runners, spectators, volunteers and staff.”
