• 1975, age 61
LaLanne had already managed to swim the length of the Golden Gate Bridge underwater, with the help of scuba gear, in 1954. Two decades later, at the age of 61, he did it again, but this time, he did it while towing a 1,000-pound boat, his hands and feet bound. Throughout his 60s, LaLanne repeated several feats he accomplished in his 40s, but upping the ante to make the feat more challenging.