Therefore, philosophical views have strongly influenced the Ayurvedic way of thinking. These elements do not exist in isolated forms, but always in a combination, in which one or more elements dominate. Doshas are the physiological factors of the body. They are to be seen as all pervasive, subtle entities, and are categorized into vata, pitta and kapha. Vata regulates movement and is represented by the nervous system.
Pitta is the principle of biotransformation and is the cause of all metabolic processes in the body.
Kapha is the principle of cohesion and functions through the body fluids. Together, these three doshas determine the physiologic constitution of an individual. The three main waste products are urine, feces and sweat. The respective products of these three stages are sweet, sour and sharp. This assimilation takes place successively.