Juliet Dunlop: Loneliness of long-distance swimmer WHEN Diana Nyad crawled, then staggered, onto the beach at Key West this week, she somehow managed to say a few words. Exhausted, sunburnt and swollen, the 64-year-old endurance swimmer had just spent two days and two nights in the ocean. "I've got three messages" she announced. One is we should never, ever give up. Two is you're never too old to chase your dreams. Three, it looks like a solitary sport, but it is a team. Nyad had just become the first person to swim from Cuba to the United States without the protection of a shark cage - an incredible achievement for anyone, let alone a pensioner. It had also taken her some 35 years to do it. Nyad has spent a lifetime breaking records. She'd already swum around Manhattan Island and made the crossing between Florida and the Bahamas, but had never quite managed the treacherous Havana to Florida route - until this week. And even now, she can't really explain why or how she did it. Maybe no-one can. Technique and technology played a part, but her story is really one of amazing physical and mental toughness, and not only in the water. Certainly, it's almost impossible to decide which part of her 110-mile journey - the equivalent of swimming the English Channel five times - is the most impressive. Thinking about it, it's difficult not to put her fitness at the top of the list. Nyad couldn't stop, couldn't rest and couldn't cling to the side of her support vessel. She had to cope with the shifting Gulf Stream currents, the endless miles of open water, and most of all, the pain. She faced nausea, dehydration and hallucinations. Then there is what can only be described as her courage. Nyad had very little protection from potentially deadly shark attacks or the swarms of venomous box jellyfish which had scuppered previous attempts. But as impressive as all of that is, it is her perseverance which sets her apart. This was Nyad's fifth and final attempt at crossing the Florida Straits. She'd admitted it was probably impossible, particularly given her age, but something kept driving her on. It wasn't about setting another record or winning prizes. This was a personal quest; a poke in the eye for the doubters and the people who said she was too old to try again. That's the reason thousands of supporters cheered her on, why TV networks followed her every stroke and President Obama sent her a congratulatory Tweet when she finally made land. There is, of course, something fascinating about the psychology of such individuals. Nyad belongs to a breed apart, a rare group capable of remaining wholly and completely focused on a goal - sometimes at the expense of everything else. She compared her attempt to climbing Everest, although her swim was probably more risky - she nearly died last time. But even that didn't stop her. And although she had a support team, including shark divers armed with customised cattle prods, a jellyfish expert and a doctor nearby, the life of a long-distance swimmer must be a lonely one. For all those miles, it really was just her and the sea. She coped, by humming her favourite songs in her head and by repeating her mantra to "find a way"; sheer willpower carried her across the ocean. Few of us can imagine putting ourselves through something half as challenging, but sports extremists like Nyad - athletes who test the limits of human possibility - symbolise something quite different, something difficult to define. Psychologists put it down to self-belief; the ability to visualise that something is possible. That certainly seems to be the case with Nyad. Friends had pleaded with her not to put herself through it, to consider giving up, but she never stopped trying, not in all those years. So, what are we to make of Diana Nyad? Is she just a super-fit fluke who finally got lucky? Or does she stand for something far more inspiring? Certainly, it's easy to mock people when they go all misty-eyed about dreams and never giving up, but in this case, it's absolutely true. In the end, no shark dared cross her path, no wave was too big and the years just drifted away. Perhaps she is just a hero.