A Sheffield Half Marathon competitor collapsed mid-race on Sunday as his wife waited near the finish line for him.
Richard Coles' core temperature rose above 39 degrees celsius in warm conditions on the run. He collapsed at mile 10 of the course on Ecclesall Road South.
Wife Philippa had already finished the race and was waiting for him to arrive at their meeting point near the Crucible.
Mrs Coles was getting more worried as the minutes went by, and was eventually sent a friend to find a marshall and ask what was happening.
She was horrified to hear he had collapsed.
Mr Coles remembers little of the incident. He waved to a friend he spotted shortly before he fell.
After that, he has no recollection of events.
"I just remember waking up in an ambulance, and I didn't know how I got there," he said.
He couldn't remember his phone number, and could barely say his wife's name.
Mrs Coles said the couple had put Richard's father Keith Coles down as an emergency contact, but he hadn't been phoned about the incident.
It took the medical staff about 90 minutes to get him back to the medical tent on Pinstone Street.
"They couldn't go the direct route," Mr Coles said.
He arrived at the tent at about 12.30pm and spent the next couple of hours recuperating.
The couple left at about 3pm after being told to keep an eye on Mr Coles during his recovery at home.
The couple was raising money for Sheffield charity Caroline's Gift, which was started by a friend.
Mr Coles wasn't sure if he would take part in the Leeds Half Marathon in May.
"I'll see how it goes," he said.