A new study says that spouses have a much greater impact on their partner's health than previously known.
It finds strong associations between the physical and emotional health of older married couples - and provides important new information on the psychological toll of physical limitations in old age.
Researchers from the University of British Columbia and Pennsylvania State University tracked the emotional and physical histories of more than 1,700 older couples over a 15-year period, using data from a major U.S. survey. Participants ranged in age from 76 to 90 and many had been married for more than 40 years.
In individuals and couples, the researchers found a strong relationship between "depressive symptoms" (unhappiness, loneliness and restlessness) and "functional limitations" - the physical inability to perform such basic tasks as climbing stairs, picking up objects, cooking and shopping.
"This study shows how important marital relationships can be in determining old age health," said lead author Prof Christiane Hoppmann of UBC's Dept. of Psychology.
"Being married for a long time is a very specific situation, it really ties your lives together," said Hoppmann, whose previous research has explored happiness in older couples.
"These findings show just how interdependent, emotionally and physically, long-term couples can become," she added.
The study has been published in the American Psychological Association's journal Health Psychology.