According to several well established healing modalities (acupressure, acupuncture, reflexology, and various adaptations of the above), the hands and palms have numerous reflex points that, when stimulated,  engage the body’s healing response and prompt a gradual (sometimes near immediate) improvement in any type of ailment.
A different way to look at this is to consider that:
  1. We have receptors in the hands that are connected to sensory fields in the brain, as shown by the cortical homunculus model (our neurological “map” – see below.) Clapping activates these hands receptors (or more if you use your hands to clap on other body parts), which in turn activate a fair portion of the brain, which itself leads to the activation of various body systems and their associated healing response in ways that are experientially evident but that we still need to better understand.
  2. Clapping stimulates blood circulation, the lifeline of the human body, and this helps with literally everything.


homunculus

Hand reflexology map

K.C. Bhardwaj: Crush chronic illness with your clapping hands!

K.C. Bhardwaj is a 76-year-old man from India who says that hands clapping cured his glaucoma:
Over a decade back I was looking for a miracle cure to glaucoma. I had started lose vision in both eyes. I did not have the courage to undergo surgery. It was then I heard at a ‘satsang’ that clapping could cure diseases and that was why devotees clapped while reciting kirtans. I regained my vision in about a year just by clapping for about half an hour every morning.” 

What research shows: Clap your hands for brain power

A researcher in Israel conducted the first study of hand-clapping songs, revealing a direct link between those activities and the development of important skills in children of all ages.
Dr. Idit Sulkin says “We found that children in the first, second and third grades who sing these songs demonstrate skills absent in children who don’t take part in similar activities. We also found that children who spontaneously perform hand-clapping songs in the yard during recess have neater handwriting, write better and make fewer spelling errors.