Q: I read somewhere that happiness was linked with health and longevity. I cannot believe that. Or perhaps I do not want to believe that. Please tell me they are joking.

 A: More than simply a positive mood, happiness is a recognized state of well-being that encompasses living a good life—that is, living a life with a sense of meaning and deep satisfaction. You reflect the people you hang out with. So, select a small group of “happy” people and spend time with them.

A growing body of research also suggests that happiness can improve your physical health. Feelings of positivity and contentment seem to benefit cardiovascular health, the immune system, inflammation levels, and blood pressure, among other things. Happiness has even been linked to a longer lifespan—providing more years to continue striving for fulfillment.

Researchers found that different types of happiness have surprisingly different effects on the human genome. People who have high levels of what is called eudaimonic well-being—the kind of happiness that comes from having a deep sense of purpose—showed very favorable gene-expression profiles in their immune cells. They had low levels of inflammatory gene expression and strong expression of antiviral and antibody genes.

People who have relatively high levels of what is called hedonic well-being (as in hedonist)—the kind of happiness that comes from self-gratification—show just the opposite. Their genes had adverse profiles involving high inflammation and low antiviral and antibody expression.