Clapping leads to stimulation of receptors in the palms. These receptors carry the
sensations to the brain. In the brain there are sensory areas. These are called
parietal cortexes. The right and left cortexes have different but complementary
functions. In these areas there is representation of the body in an inverted
manner. This small body representation is called homunculus.
The hands and the face have maximum representation in this homunculus.
Hence clapping causes stimulatin of the large areas of brain [just as rubbing of
the inner aspects of the oral cavity does] and this stimulation presumably
activates all the body systems and thereby improves the health.
Knowing this; probably in an intuitive manner, the clapping has been integral part
of devotional hymns, music, prayers etc. This link of religious or spiritual
practices and health has to be appreciated.
Clapping behavior is unmistakable right from the childhood days and in times of
exclaimations or ecstatic responses. [Cf: Superliving: Dr. Shriniwas Kashalikar]