1. Lewis Pugh swims in the "vulnerable ecosystems of the world's coldest waters" to raise awareness for environmental awareness. In his past endeavors, he has done many heroic (and life-endangering) feats, like swimming in the Arctic. This particular feat earned him the title of "human polar bear" because if you take it literally, polar bears live in the arctic.
2. Pugh's latest feat was his most dangerous yet - conducting five swims in Antarctica's Ross Sea. It was spread over three weeks, and each swim was only 20 minutes. However, more than that amount could potentially kill him. Plus, he had to watch out for leopard seals and killer whales that roamed the Ross Sea. He hopes to convince officials to place a protection area the size of Germany, France, and the United Kingdom before the ecosystem is affected.
3. Besides training in frozen pools and gaining some weight (following the way of the whales XD) he used a technique unique to him. It's called 'anticipatory thermogenesis' which is really cool - the method raises his body temperature and his heart rate using only his mind!
To conclude, I don't think he's crazy. He's just trying to make a difference, I suppose. To go to crazy heights like that for a worthy cause and to protect the environment and animals is just AWESOME. Go Lewis Pugh!!!