Dom Dozier, from Norwich, had been training for months to prepare for his first marathon, held in Manchester on April 19. 

The 30-year-old said he had felt "really strong" going into the race and had regularly taken part in half-marathons with his run club over the past two years. 

Dom Dozier said he felt "really strong" on the race day (Image: Dom Dozier)

On the day of the marathon, Mr Dozier said he was fine until he started feeling light-headed just two miles from the finish line. 

He presumed he was dehydrated and decided to walk the final two miles when his vision went blurry and he suddenly collapsed. 

"I was so shocked and I started to panic when my body tensed, and I couldn't manage to speak,” he explained. 

Dom Dozier was rushed to hospital after collapsing (Image: Dom Dozier)

"The second seizure was by far the scariest and I remember my fiancé saying, 'think of the kids'. 

"That moment put everything in perspective for me and I was just thinking about my two children." 

After collapsing, he was rushed to hospital where he was told the oxygen levels in his brain were low due to dehydration and low sodium levels. 

Dom Dozier during the Manchester Marathon (Image: Dom Dozier)

Mr Dozier has since made a full recovery and is urging people not to sign up for a marathon, thinking it's "a fun day out", and instead be aware of how "challenging" it is. 

"It's frustrating as running got me out of depression and I didn't want this to put me off,” he added. 

Dom and his older sister Rebecca as children (Image: Dom Dozier)

Mr Dozier has entered the ballot for next year's London Marathon and will also be taking part in the Manchester Marathon again, saying the incident has "spurred him to be better". 

He will be running to raise money for Meningitis Research Foundation in honour of his older sister Rebecca, who his family lost to meningitis when she was just eight years old. 

© Norwich Evening News