"A giving heart can glow with health"

If optimism and high spirits have beneficial effects on the body, what about on natural extension of being a pleasant person-doing good deeds for others?

Altruism is good for you, according to a study by Harvard University psychologist David McClelland. He showed subjects a film of Mother Teressa tending to the sick of Calcutta, then analyzed their saliva and found an increased presence of immunoglobulin, an antibody that helps fight respiratory infections,

That research, taken in conjunction with studies showing the ill effects of hostility, social isolation and stress, suggest that a giving heart can glow with health. Just reflect on your own moments of genuine generosity and recall how you felt; most people describe it as a good feeling, Imagine what it would be to have that warm feeling all the time.

Excerpt from "100 ways to live to 100"