If you already practice yoga, hot yoga is not dangerous. But for beginners who jump, instead of ease, into this heated exercise, there may be a risk of overheating. Doctors consider internal temperatures of 104-degree and up to be dangerous, which participants sometimes creep close to in classes that are overheated. Women who are pregnant and people with diabetes or any cardiovascular problem, including high blood pressure, should not do hot yoga.
If you're just starting yoga for the first time alone and at home, opt for a non-heated practice. It has many of the same benefits and none of the risks.