There's an old maxim — keep your spouse happy, and you'll stay healthy — that behavioral analysts say may be true.

Researchers have long linked mental well-being — a sense of satisfaction — with good physical health. So if your spouse is happy, your mental well-being is better off. But a recent study published in Health Psychology, and reported by The New York Times, suggests physical health is also linked to a happy spouse.

The research is based on a large study — 1,981 heterosexual couples aged 50-94 were periodically surveyed since 1992 on how happy they were. At the same time intervals they were surveyed on health.

By far, those with an unhappy partner had more health issues, exercised less and rated their overall health worse than those who had a happy partner.

William J. Chopik, an assistant professor of psychology at Michigan State University, and lead study author, said that a happy spouse provides social support, and encourages healthy habits — such as diet and exercise — which sustain good health. “We’ve known for a long time that when we surround ourselves with happy people, we’re happier. But now we know that it not only makes us happier, but healthier as well,” Dr. Chopik said.