But then I read about endurance swimmer Martin Strel (pictured right), who's visiting Australia next month to promote his documentary Big River Man.
The doco follows the 5268-kilometre journey Strel undertook to swim the length of the Amazon River starting in Peru, as high up as he could get a support boat, and ending in Brazil at the Atlantic Ocean.
For someone like me who considers the 2.7 km Big Swim (from Palmy to Whale) a marathon, Strel is a bloody freak.
How did he do it? There's the obvious stuff, like he trained five hours a day in preparation for the swim and took along a highly professional support team, including a river navigator and a virtual medical team.
But here's the surprise - the big man from Slovenia credits his homemade wine as a superfuel that kept him going for 66 days, even after 'flesh-eating' piranhas tore through his wetsuit and he endured numerous horrid tropical ailments including dengue fever.
*"I drink two bottles of wine, but you have never seen me drunk. Don't take aspirin, just ask me for my wine," he told a journalist.
Strike me pink! No wonder Strel managed this amazing feat. Or is it a wonder that he did? He's pickled!
Here's to you Marty. You have the heart of a lion and the constitution of a rugby league team.
*Do not attempt this at home before a swim! You will sink. To the bottom.