I"ve tried hot yoga and its stupid in theory and in practice. Its not true that your body sweats out more toxins. 99% of toxins are excreted through your kidneys and bowel function. Mostly what you lose when you sweat is body salts and water. These are not toxins.
Its a guess but i've been in india and i understand a little about the way they think.
The source of this idea is from india. India is a very hot country. Mostly they do not have air conditioning though they do have the mountains.
Indians have many non-scientific explanations for the way the body works. And they will call it scientific but what htey mean by scientific is not the same was what is meant by science in the West. When the west refers to science they mean modern science which means that any theory can be disproved.
In the east there is not bothering with that. Science is merely close observation and interpretation. Hence all the weird and wonderful theories.
That said, there are many wonderful ideas that have come out of india, yoga not in the least. I love yoga. But hot yoga is stupid because you are uncomfortable for no demonstrable good reason.
Perhaps the reason why you family feels good doing this is yoga is because they are exercising. And yoga is a lovely type of exercise in all its forms. It works all different parts of the body without any expensive equipment. The classes are usually conducted in a calming sort of way. Attention is paid to your state of mind. And so on.
If they are happy with their yoga it can do no harm unless they are dehydrated when they start. If they are doing something simliar to the one i did, which was ashtanga, then its very strenous and it will be good cardio as well as build muscle, work the brain a bit. Its a really good work out for the whole body. Just don't believe the junk about being hot.
