Former Wales rugby international Alix Popham is in hospital after suffering from suspected concussion whilst taking part in Ironman Wales.
The 43-year-old retired player, was competing in the triathlon event in Tenby on Sunday when he was forced to withdraw after being kicked in the head during the swim.
There are even reports the athlete was unable to recognise his wife when exiting the water.
Popham has been hugely vocal about his diagnosis of his early onset dementia at the age of 40.
His charity, Head for Change, supports people like him who are suffering the effects of a career of intense professional rugby.
The Ironman he was taking part in to raise awareness of the condition, involves a 2.4-mile sea swim, 112-mile bike ride, and a full marathon.
Athletes are expected to complete it within 17 hours.
Lobby group Progressive Rugby described it as a "cruel and ironic twist of fate" that Popham had to withdraw after spending months training to raise money for concussion education and support.
The group added on social media: "Update: Alix was unable to recognise wife Mel as he came out of the water.
"Although dizzy and suffering a headache he appeared okay but his condition has deteriorated and he is currently being transferred by ambulance to hospital. Updates posted with permission."
Popham, who won 33 caps between 2003 and 2008 and played at two World Cups, was competing in aid of Head for Change, a charitable foundation calling for positive change to aid brain health in sport which also supports ex-players suffering from neurodegenerative disease.
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