In the yoga world this new fashion at the moment seems to have something called soothed yoga (also known as Bikram Yoga). As its name implies, it is practically yoga, which is performed in a hot room (similar to a sauna). These "hot rooms" are usually between 90 and 105 degrees, and for some very good reasons they are on this amount of heat.
First, because of such extreme heat it sweats, and this means removing many toxins from the body (which makes the process healthier)
Second, heat makes the muscles loose in colder environments, that is, easier to stretch
It also means that it is simply in a warm environment that releases tensions from the body that can build up over time (especially after hard daily work) and can cause pain.
So what's the heated yoga? Well, it's obvious that you have to do it somewhere (that is, a heated room) and you need some kind of yoga mattress or towel to lie. In addition, I suggest that you bring some liquid (for example, a bottle of water). That is why such a hot room is so sweaty as crazy, so it's a good idea to have something that keeps the fluid.