Reflexologists posit that the blockage of an energy field, invisible life force, or Qi, can prevent healing. Another tenet of reflexology is the belief that practitioners can relieve stress and pain in other parts of the body through the manipulation of the feet. One scientific explanation may be that the pressure received in the feet may send signals that balance the nervous system or release chemicals such as endorphins that reduce stress and pain. These hypotheses are rejected by the general medical community, who cite a lack of scientific evidence and the well-tested germ theory of disease.
Many civilizations have practiced reflexology. Evidence of this has been documented on four continents: Asia, Europe, Africa, and North America. The most common theory is that the earliest form of reflexology originated in China, as much as 5000 years ago. The early Taoists are credited with originating many Chinese health practises. The Cherokee tribes of North America to this day practise a form of reflexology that they continue to pass from generation to generation. Reflexology travelled across India, Japan, Asia, and China. Traditional East Asian foot reflexology is called Zoku Shin Do. This is the foot portion of the Japanese massage technique. The roots of Zoku Shin Do go back to ancient China and are over 5000 years old. Many changes took place in zone therapy, or reflexology, as new knowledge was added. In China, reflexology reached a new level. The practice of acupressure using the fingers turned into the practice of acupuncture using needles. The study of the reflex points still existed, but the knowledge was linked or added to and taken in a new direction—the direction of meridians. The Chinese concept of meridian therapy is an important part of the foundation of reflexology.
The precise relationship between the ancient art practiced by the early Egyptians and reflexology as we know it today is unclear because different practices involving the manipulation of the feet to effect health have been used throughout the world. The precursor of modern reflexology was introduced to the United States in 1913 by William H. Fitzgerald, M.D. (1872–1942), an ear, nose, and throat specialist, and Dr. Edwin Bowers. Fitzgerald claimed that applying pressure had an anesthetic effect on other areas of the body. Reflexology was further developed in the 1930s and 1940s by Eunice D. Ingham (1889–1974), a nurse and physiotherapist. Ingham claimed that the feet and hands were especially sensitive, and mapped the entire body into "reflexes" on the feet. It was at this time that "zone therapy" was renamed reflexology. Modern reflexologists in the United States and the United Kingdom often learn Ingham's method first, although there are more recent methods.