Marry a spouse who exercises. That is the takeaway from a new Yale study that shows that wives whose husbands complete more physical activity are less depressed.

The researchers in the study, which focused on aging couples, found that more exercise predicts better mental well-being in aging males, but this correlation between physical activity and mental health is less apparent in females of the same age group. But wives’ mental health is influenced by their husbands’ exercise. The article appears in the April issue of the Annals of Behavioral Medicine.

“There are a lot of studies showing that physical activity predicts mental and physical health, and especially as you get older,” said Joan Monin, study lead author and professor of epidemiology at the School of Public Health. “But many elderly are married and live with other people and especially their spouses, and their spouses’ behaviors and feelings tend to be related to [their own], so they have an important influence on each other.”

Existing measures for enhancing well-being focus on individuals and rarely target couples, Monin added.

Janet Currie, director of the Center for Health and Well-being at Princeton, which encourages research on health determinants, said the research study is innovative in going beyond the effects of exercise on individuals to the effects of their family relationships.

While existing theories state that exercise increases blood flow and thus improves mental well-being for both males and females, the spouse influence is not as widely known, said Joan Bloom, professor of health policy and management at University of California, Berkeley.

Monin said the different types of physical activities between husbands and wives probably explain why physical activity affects mental health more for husbands than for wives. While husbands usually take part in group exercise that is more active and fun, wives’ physical activities often include household chores, she said. The former type of exercise might be more beneficial for mental well-being than the latter, she added.

Besides the different physical activities, wives also focus more on relationships than husbands do, Monin said.

“They tend to do things that their husbands are doing, but the husbands focus more on themselves,” she said.

Women are also more often the caregivers of their husbands, so their physical activity may depend on their husbands’ ability to complete physical activity, Monin said. These differences could explain why husbands’ physical activity influences wives’ symptoms of depression but not the other way around, she added.

Although the study does not establish causation between spouses’ physical activity and mental health, William Satariano, professor at the University of California, Berkeley School of Public Health, said the relationship is plausible.

“Maybe a person engaged [in physical activity] has better physical and cognitive health,” said Satariano, who teaches a class called “Aging and Public Health” and conducts research on physical activity among the elderly. “Because of that, they contribute to creating a healthier environment, defined broadly, and so their spouses live in a happier setting.”

Satariano said the research study has important implications both for future research and intervention programs targeted at the elderly. He said the study probes a very exciting area: the significance of spousal relationships and their effect on health.

The study could also lead to the development of new programs designed to protect caregivers, who suffer from elevated health risks in part due to the stress of caring for their spouses, Satariano said.

Approximately 15 percent of adults aged 60 and over worldwide suffer from a mental disorder, according to a 2010 World Health Organization global burden of disease study.