Ashtanga (Power Yoga) is a great calorie burning tool as it is very intense and fast paced. Bikram Yoga also burns calories and is practiced a lot by athletes and celebrities. Bikram is a mix of aerobic cardiovascular and fat burning exercises. It is also called 'Hot Yoga' because it is performed in yoga rooms heated to 100 degrees. Iyengar yoga is effective as its postures are held for a longer period of time and this forces the muscles to work harder. For these programs to be effective they must be practiced for a minimum of ten times per month.