How singing helps your health
 

 "Aging Study Yields Powerful Results.
Just concluded in 2004, one of the most specific studies on singing and health also focused on aging. The Levine School of Music in Washington, D.C. formed a Senior Singers Chorale in 2001 as part of a wider study examining how singing under professional direction could affect the health of people 55 and older........"Singing Enhances Immunity, Well-Being The results of a study conducted at the University of Frankfurt in Germany were released earlier this year, and add to the case that choral singing has
a positive health impact" Click here for the complete article Chorus America - The Singing-Health Connection
Singing For Health
By Dr. Ben Kim on November 25, 2004
"Looking for a fun way to get and stay healthy? Try singing on a regular basis. But not any old singing will do. The kind of singing that will provide you with significant health benefits has to come from deep inside your chest, even from your abdomen. ....The idea is to use your diaphragm - the large muscle that separates your chest and abdominal cavities - to push air out through your vocal cords. Using your diaphragm to sing is a good way to promote a healthy lymphatic system which in turn will promote a healthy immune system."
 
"Singing Reduces Stress and Pain Studies have linked singing with a lower heart rate, decreased blood pressure, and reduced stress, according to Patricia Preston-Roberts, a board-certified music therapist in New York City. She uses song to help patients who suffer from a variety of psychological and physiological conditions. "Some people who have been traumatized often want to leave the physical body, and using the voice helps ground them to their bodies," Preston-Roberts says. "Singing also seems to block a lot of the neural pathways that pain travels through."

 P.S. I'm 68 years old and my last blood pressure reading a couple of months ago was 111 over 57.
Why is singing so beneficial?  I believe all that is quoted above has a lot to do with it.  I also think that breathing the way a singer breaths probably has more to  do with it. Opera singers are not know for their svelte shapes, right?  However, according to a 20 year study of singers at the New York State Opera Company, their singers had a life span that was 7 years longer than the average life.