Raymond Tate passed out from dehydration in the early hours yesterday at the marathon game, which started at 10am on Saturday at the Abercorn Conference Centre at Reid Kerr College in Paisley, Renfrewshire.
Mr Tate and his playing partner Craig Beevers had been thinking up words for 15 hours when the 55-year-old from Paisley became ill.
He was taken by ambulance to the nearby Royal Alexandra Hospital, where he was later moved to the Acute Medical Unit and kept in for observation.
An NHS Greater Glasgow and Clyde spokeswoman confirmed yesterday his condition was stable.
The Scrabble World Record Challenge was organised by the Rotary Club of Paisley to raise funds for Rotary International's End Polio Now campaign.
The event was streamed live on the Paisley club's website, attracting viewers from as far afield as Russia, Bermuda and the US. The aim of the game was to beat the record for the highest score of 162,171 in 24 hours.
Mr Tate had previously attempted the challenge last August, along with teacher Siobhan O'Tierney, but the pair failed by 12,000 points.
Organiser Tom Clark, a member of the Paisley club, was "desperately disappointed" for the duo and is convinced they would have beaten the record.
He said: "They were playing faster and scoring higher than necessary. They weren't getting any slower, they actually seemed to be playing faster, so I think the record was unlikely to survive. I know how important it would have been to both of them, to have been crowned world record holders."
Mr Tate's wife, Julie, also a keen Scrabble player, was at the weekend challenge. She said: "I actually wasn't watching at that point and had my back to him. I heard a loud crash and thought one of the cameras had fallen over. I then turned round and Raymond was on the floor."
His Scrabble partner Mr Beevers said: "He'd been fine prior to that. He stood up for a break. He was looking at me and then stumbled backwards. He was still conscious and was talking to me while we waited for the ambulance."
Mr Beevers, 30, had travelled from Teesside to take part in the challenge. He has been playing competitive Scrabble for nine years, gaining the title of National Scrabble Champion in 2009 and won Channel 4 word challenge show Countdown five years ago.
He said: "Julie and I went back to the hospital to see him. It was great to see him looking so well before I left."
Mrs Tate added: "I'd been worried for him but when I got to the hospital this morning he was sitting up and was quite cheery."
The Rotary Club and the duo are keen to reschedule the challenge.