Medics on the finish line of this year's Dublin Marathon treated three times more athletes than in previous years.
Organisers say the unseasonably warm weather is the reason why more runners struggled this year.
Of the 12,517 starters, 270 did not finish - a drop out rate almost double last year's.
A hospital tent treated about 300 people at the finish, compared to 100 in a typical year.
Health Correspondent with The Irish Mail On Sunday, Niamh Griffin, says most of the people treated were suffering from heat exhaustion:
