Caldarium it is actually a fancy Roman word for a heated room. In the old days they would have rooms heated by fire and coals. By adding cold water to the coals you can create steam, almost like a sauna today. A sauna is usually dry heat, and next to it in one corner of the sauna there is usually something like a stove that generates heat. By adding a bowl of water to a particular heating component you basically make steam. So a caldarium is just an old word for what is now known as sauna or steam room. A heated environment promotes sweat production. That's why exercise is good for you. It promotes circulation and sweating therefore eliminating toxins through your body rather than just through urine. You want to drink a lot of water to aid your liver and your kidneys in elimination. Sweating is great for reducing inflammation and for joint pain as well as for relaxing the muscles.