Noise pollution is one of the biggest health hazards and sources of stress. Sound waves continuously penetrate your body and you can't turn them off (even if you "tune them out"). Noise immediately causes your heart to race and your breathing to speed up. It also releases extra fat into the bloodstream and causes magnesium levels to fall. Children who live near noisy highways, airports and railroads have lower reading scores and slower language development.
Healthy sounds, by contrast, improve wellbeing at every level. Western science is now validating ancient knowledge, such as Nada Yoga, the yoga of sound. Current medical studies show that the right sounds promote healthy functioning of the immune, endocrine and autonomic systems. In one study, the simple act of humming cleared up stuffy nasal passages. In another, they found that nitric oxide levels in the sinuses were 15 times higher when humming. Nitric oxide relaxes muscles, increases blood flow, improves digestion and helps focus the mind.