The four men who died in the Great North Run were aged between 28 and 52, a coroner's office has confirmed.
Phil Lewis was taking part in his 24th Great North Run
The youngest victim was Rueben Wilson of Leeds - Kieran Patching of Kent was 34 and David Mahaffey of York was 43.
The fourth victim was deputy headmaster Phil Lewis, 52, who taught at Moorside Community College Consett, Co Durham.
A statement from Bupa Great North Run said the deaths were "deeply unfortunate" and that there were 16 ambulances on stand-by at the event.
More than 50,000 runners took part in the 25th half-marathon event in warm temperatures on Sunday.
Bupa said there were medical facilities at every half-mile along the route as well as ambulances, two paramedic bikes and two field hospitals at the finish line.
There were also five water stations on the course and three specially constructed mobile shower units, Bupa said.
The statement added: "As with any large scale participation event the entry form states that all participants are strongly advised to consult their doctor prior to undertaking any exercise programme.
Runners in fancy dress took part in the run
"Participants received comprehensive pre-race information about training, consulting a doctor, medical points on the course and further day of the race advice."
Many of the runners reported feeling extremely hot as temperatures rose during the race.
Runner Paul Bouch, 25, said: "After about 10 miles the ambulances were everywhere and some of the people looked in a bad way.
"But it was difficult to get the ambulances to the roadside because it's just so packed with people."
Sports Minister Richard Caborn said advice given to athletes taking part in running events might need to be updated following the deaths.
He said: "It is tragic. But I would not want this to distract away from what is a big family event which was brilliantly organised. Every medical precaution was taken and the back-up was there."
Brendan Foster, chairman and founder of the Great North Run, said: "Myself and everyone associated with the event are saddened by the news that four people died during the Great North Run."
Eritrean Zersenay Tadesse in 59 minutes 5 seconds, won the race, beating the previous record by one second.
Ethiopian Deratu Tulu clinched victory in the woman's race in 67 minutes 33 seconds.