It has been suggested that practicing Yoga in Hot rooms helps in bending and improves the general flexibility of the body. Although, this might be true, increased heat also increases the heart and breath rate of the body, which is not good for asanas. Slow rhythmic breathing is essential to get the benefit of the asana. If you want to sweat a lot, you might as well do Aerobics.
Activity done in Hot rooms will lead to rapid dehydration and may lead to dizziness or head aches. It is also not suitable for pregnant women and people with hypertension and heart problems.Contrary to popular belief, excessive sweating is in no way improving the detoxification of the body. You are losing a lot of water and minerals unnecessarily!