Narrator: This is Science Today. It's been known for years that married people tend to live longer than those who stay unmarried. Now a study from the University of California, Berkeley shows that a happy marriage makes for a healthier old age. Cenita Kupperbusch, a doctoral candidate in psychology, says a long-term study of aging couples proves that a good marriage can be the best medicine-at least for men.

Kupperbusch: Husbands who had increases in marital satisfaction also had increases in their health. On the other hand, this was a positive relationship. So husbands who had decreases in marital satisfaction also showed decreases in health.

Narrator: The study followed 78 elderly couples over a period of thirteen years. Using surveys and observation, the researchers found a clear link between marital satisfaction and health. But Kupperbusch says that the reason for that link is not yet known.

Kupperbusch: We don't know that changes in marital satisfaction are necessarily causing changes in health but we know there is some relationship between those two. It could be that changes in health are causing changes in marital satisfaction.

Narrator: For Science Today, I'm Larissa Branin.