When the five eternal substances - earth, water, fire, air, and space - combine to form the human body, they do so by creating three vital energies, or doshas. The three doshas construct and maintain our physical beings, and they determine, by their proportions, our unique characteristics and traits.

Vata is the most powerful of the doshas. Formed by the interaction of space and air, Vata is movement, the body in motion. It is the energy of respiration, heartbeat, nerve impulse, and muscle contraction. As such, it circulates the blood and lymph, draws and expels air from the lungs, moves food through the digestive system, and eliminates waste.

Pitta is formed by the interaction of fire as energy of change and water as agent of change. The polarity of these two elements plays an important role for Pitta. Pitta regulates the body, controlling its metabolism. It is the body in transformation. Thus it handles digestion of food, release and absorption of hormones, production of heat, and cooling. Where Vata moved nerve impulses to and within the brain, Pitta converts those impulses to thought.

Kapha combines the structural properties of earth with water in its role as lubricant. It builds the body and forms its structure: skeleton, muscles, organs, ligaments, tendons, and skin are the work of Kapha. And Kapha lubricates the body, ensuring the smooth function of joints. With strength, stability, and solidity, Kapha is the body in repose.

Our physical constitution and our health both depend on the balance and interplay of the tridoshas. But to fully understand the energies that combine to create a human, we must also look at the three gunas, the psychic energies that constitute the mind.