For most people, the sweat that comes with a hot yoga session or an hour in an infrared sauna has a lot of benefits. Maybe sweating relaxes you, makes you feel strong, or—as you'll hear a number of people say—helps you "get rid of toxins."
If hot yoga is your thing, by all means, keep it up. A heated asana practice is great for building strength and flexibility, and infrared saunas promote relaxation and can boost happiness in the cold winter months. But if "sweating out toxins" is your goal, read on.