When we think about yoga, we think of people sitting in a meditative posture. Yoga works specifically on the physical body to obtain greater flexibility and greater physical strength. The postures not only work on your flexibility but also create greater efficiency within your physiological functions, e.g., breathing, circulation, digestive, endocrine, and lymphatic systems.
This is a vigorous form of yoga which is performed inside a studio heated to 105° F (40°C) with a humidity of 40 percent. Its formal name is "Bikram yoga." It is a 90-minute program consisting of a series of 26 postures, with lengthy, forceful, well-controlled contractions of all major muscle groups.
While regular yoga will focus on different body postures and flexibility, hot yoga involves an environment with much higher heat and humidity. This creates a much higher oxygen demand from the body than in normal conditions. The high requirement for oxygen makes the lungs expand to a greater capacity to hold more oxygen.
In regular yoga, the heat generated by a muscular workout is transferred to the skin and is dissipated into the ambient environment; the internal body temperature remains constant. In hot yoga, the heated environment forms a negative gradient that the body must work against the natural influx of heat from the room. More heat is generated by the muscles during practice, and more energy must be spent to transfer the heat to the skin and out of the body.
Hot Yoga practitioners have muscles that are trained to be more efficient in oxygen absorption and dissipation of heat on a metabolic level. Hot yoga sounds more comprehensive than regular yoga. Experts and pros will go for hot yoga, while regular yoga will be done as leisure and with less comprehensive activity.