Bikram yoga is a substyle of hatha yoga developed and licensed by Bikram Choudhury. It consists of 26 postures designed to develop strength and flexibility while being performed in a room heated to 105 degrees Fahrenheit. Like other forms of yoga, it also has a meditative aspect that can relieve stress. How quickly you'll notice the various effects of Bikram yoga depends on which benefit you're most concerned with.
The combination of challenging exercise, stretching and breathing meditation in Bikram yoga create one benefit of the exercise that you can feel during the workout session and for hours afterward. Stress reduction through Bikram yoga is accompanied by physiological changes including regulated heart beat, controlled breathing, reduction of anxiety and reduction of stress hormones like adrenalin. These changes happen as an immediate response to light to moderate exercise such as Bikram yoga.
You are likely to come out of a Bikram yoga session a pound or more lighter than you went in. However, this is water weight loss that will go right back on as soon as you rehydrate yourself. Bikram yoga does burn calories, however: up to 750 per 90-minute session depending on your weight and intensity of practice. Since 1 pound represents about 3,500 calories, you could lose a pound from Bikram yoga after about five sessions.
When you stretch muscles, as in many of the 26 poses of Bikram yoga, those muscles gain a fractional amount of greater elasticity and range of motion. If you stretch frequently enough, this can improve your flexibility. According to Bruce Lee in "The Art of Expressing the Human Body," flexibility is one of the slowest physical attributes to improve. Expect to practice for a number of months to see meaningful improvement in your flexibility.
The postures of Bikram yoga -- and most other forms of yoga -- use your body weight to give your muscles a resistance workout. You may see noticeable gains in your strength in a matter of weeks with regular Bikram yoga practice. However, Stuart McRobert warns in "Brawn" that strength gains often work in a "step pattern." This means you may experience a plateau where you make no new gains for several weeks, then gain strength again for several more.
Common Sense Approach
In order to see results, attend regular Bikram yoga sessions. If you only go a few times each month, you'll experience slow gains, or no gains at all. As with any other workout program, you should check with your doctor before taking on a Bikram yoga regimen.