Mantra Sound effects on our mind and body
Chanting 'Om' gives energy and develops mental powers. There is a sattvik effect on the brain, stomach and subtle senses.
Chanting 'Hreem' has a good effect on the digestive system, throat and heart
Pronunciation of 'Hram' has good effect on stomach, liver, spleen, intestines and uterus.
Chanting of 'O' leads to the development of energy.
Mental powers develop by chanting 'M'. Perhaps that is why the sages of India would have preferred the word 'mother' for the birth mother.
Pronunciation of 'aa' has a good effect on vitality, lungs, chest etc. There is relief in cough, asthma, tuberculosis etc. Laziness is removed.
The pronunciation of 'A' has a good effect on the heart.