A man with Motor Neurone Disease (MND) is attempting to break a Guinness World Record after his "shock" diagnosis.
54-year-old Mark O'Brien, from Slip End in Bedfordshire, said he has always been extremely active, but first noticed something was wrong two years ago when he was struggling to grip onto his tennis racket towards the end of matches.
He was formerly a keen swimmer, rugby player and tennis player, but after multiple appointments and tests, he was diagnosed with MND in March 2022.
MND is a terminal illness that impacts the brain, nerves and muscles, also commonly known as ALS, for which there is currently no cure.
Mr O'Brien said: "It was a real shock, I actually took myself away on holiday because I was mentally shot.
"It was a really dark time, and then I thought right i'm going to do something positive, and I know I can swim, so I contacted the Guinness World Record people."
Mr O'Brien has been training at beauty-spots like Willen Lake in Milton Keynes to break the world record for the longest, unaided, open-water swim for someone living with MND.
The official attempt will take place on 24 September, and will see him swim 10,500 metres in around four and a half hours.
Mr O'Brien said: "The training has been really tough, I think it's been tougher in the last few months. I was swimming everyday, but because of the condition I can't do that anymore. So, I've been breaking it into two big swims."
He added: "Sometimes I can't even walk to the end of my garden without tripping over my own feet, but when I'm in the water, there's a relative normality, probably because of the support the water gives you.
"So, I'm excited to be in the water.
"I'm a little concerned over the temperatures because if it gets too cold, my hand will freeze and my leg will freeze. So I've been training swimming with one arm and with no legs. I've been through all kinds of eventualities.
"But I'm really excited. I feel really lucky and privileged that I'll be able to do it."
Mr O'Brien's three children, 24-year-old Lauren and 21-year-old twins David and Georgia, will be joining him for the last kilometre.
"It will be a tremendously emotional time for everybody watching, but also nearing the end of the event it'll give me all the added energy I need, and I want to leave them with memories for a lifetime," Mr O'Brien said.
One of the goals of the event is to raise awareness of the condition and to raise money for the charities supporting people and helping to find a cure.
He has already raised almost £9,000 through his JustGiving page. He hopes to raise £25,000.
The challenge attempt will take place at 8am at Denham Water Ski Club in Uxbridge.
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