"When you kitesurf, you really focus on kitesurfing. Nothing else. You don't want to make a mistake," says five-time entrepreneur Constantin Bisanz, 41, who most notably sold Brands4Friends, a fashion e-commerce site, to eBay for $220 million in 2011. He says kitesurfing is an antidote to the everyday pressures of business--specifically, his new nutrition and wellness startup, Aloha. So whenever he can, he straps on a harness, unfurls his kite, and endures gale-force winds racing across the waves.

Unlike business, kitesurfing offers no room for error and dire physical consequences for failure. He's so passionate about the sport that in 2011, he and a small team became the first to kitesurf the Bering Strait between Alaska and Russia, crushing endless gray waves, bundled up in drysuits to stay warm. "I always like to ride in very hard conditions," he says. "The stronger the wind, the more I like it."

Usually, you'll find Bisanz surfing the waters a little farther south of the Arctic Circle, off places like Mauritius, Brazil, and Maui. Although he kitesurfs to take his mind off business, Bisanz still mixes a little work into his play: He and Richard Branson recently gathered some fellow kitesurfers, entrepreneurs, and investors for kitesurfing off Branson's Necker Island. "I believe that kitesurfing is the new golf," says Bisanz. "It's great for networking." Provided you can hear one another over the howl of the wind.

From the February 2015 issue of Inc. magazine