At the heart of the Ayurvedic system lie the five elements. All matter in our universe, including our bodies, is composed of these elements in combination: space, air, fire, water, and earth. Each element is a symbol representing specific qualities and processes. It is the qualities associated with an element that are present in us, not the element itself. To understand this concept better, let's look at each element individually. Space (Akasha) is the emptiness in which all the other elements exist. It represents the nature of the void. To grasp the concept of Akasha, consider a doorway. There is nothing there, but that is the secret of its usefulness. Similarly, the spaces in your body - the lungs, the nostrils, the mouth, the stomach - are useful because they are empty. And with the concept of space come two related concepts: distance and location.

Air (Vayu) is matter in its gaseous phase. It is movement, fluidity, formlessness. It can be compressed or rarefied. It can be a gentle breeze, or a force five gale. It manifests itself in the body as movement, pulsation, expansion, and contraction.

Fire (Agni) is the energy of transformation or change. Oxidation, chemical reaction, the exchange of energies, the conversion of matter from one phase to another: all are represented by fire. In the body, fire is metabolism, enzymatic changes, digestion, and thought.

Water (Jala) is matter in its liquid phase. Able to act as both solvent and lubricant, water is the agent of change. It represents our blood, carrier of oxygen; our saliva and digestive fluids; our hormones; our sweat; and our urine. It is the mover of nutrients and the eliminator of waste products. It is the sea of life within us.

Earth (Prthvi) is matter in its solid phase. Shape, form, and stability are in the nature of earth, thus earth forms the structure of things. Bones, hair, nails, muscle, tendon, and ligament are earth-like, as are the walls of cells and the body's covering: skin.

The five elements represent the eternal substances from which all things are formed. From these five elements arise more complex structures, such as the three vital energies, the tridoshas.