As per Traditional Chinese Medicine to have good health, the body requires water to move upward and fire downward. This is because the head and brain must remain cool and calm, while the hands and foot remain warm. When one is fall ill, you can find their head is in hot (with fire), and the hands and foot are at cold or moist. Foot tapping balances water and fire in the body and restore normal health.
Note that our foot contains 7,000 nerve endings, 19 muscles, 107 ligaments and 26 bones. In addition, foot sole has reflex-points (i.e. nerve endings) of all the major organs in our body. Thus by stimulating these points by tapping, helps to nourish the respected organs and restore normal health.