Runners and walkers make their way across the bridge during the 2017 Cooper River Bridge Run Saturday morning. Leroy Burnell/Staff

A 68-year-old man died from a heart attack suffered during the 40th Cooper River Bridge Run and Walk on Saturday.

The Charleston County Coroner's Office identified the man as John Frederick Barden of North Carolina.

Another man, a 74-year-old from North Carolina, also suffered a heart attack as he was nearing the finish line at around the two-hour mark of the race. Details on that incident were not available.

On Friday, long-time Bridge Run volunteer medical coordinator Al Hawkins was bracing for a busy day due to a forecast for relatively warm temperatures.

Temperatures stayed in the low to mid-60s until 9:30 a.m. but the combination of exertion, sunshine and minimal wind once off the bridge started to add up.

Medical staff started getting busy at about 10 a.m. when less fit participants started finishing.

"It hit the fan late," said Hawkins. "We (staff) were standing in the shade, but it was when I walked out into the street and into the sunshine that I started realizing it was warming up."

Hawkins said by 11:30 a.m. the tent at the finish line had registered 50 people needing some level of help. At the time, he was unaware how many had sought help at the medical tent at Marion Square.

One staffer there said many people didn't start feeling the effects until the end of the 6.2-mile course, with some suffering from dehydration.

Gregory Yee contributed to this report.

Contact David Quick at 843-937-5516. Follow him on Twitter @DavidQuick.