When you and your spouse promised "for better or for worse," your bodies were paying attention. Research shows that married couples are so in sync with each other that they grow more alike on a cellular level as they age.
"It's like finishing each other's sentences, but it's your muscles and cells that are operating in sync," said science writer Lindsay Peterson in a report for NPR.
The research, presented at the annual meeting of the Gerontological Society of America, came from an analysis of 1,568 married couples. Postdoctoral research fellow Shannon Mejia and colleagues at the University of Michigan in Ann Arbor found "striking similarities" in kidney function, cholesterol levels and grip strength among couples who had been together more than 50 years.
While one reason may be that people tend to marry people like themselves, this doesn't explain why people married for decades are more biologically similar than couples married for fewer than 20 years, Mejia said.
Their shared traits may be "something the couples co-created" over time, she said. (The Bible and Noel Paul Stookey famously put it another way: "the two shall be as one.")
The science behind it may be simple. Married couples share daily routines and environments, which may also explain why some long-married couples start to look alike. That phenomena has been attributed to our tendency to mimic each other's expressions, and married couples often share each others' emotions.
Of course, they also tend to eat similarly, which is why having an obese spouse doubles the chance that you will become obese, too.
Research into why couples grow to be physiologically similar has been limited, and there are still lots of unanswered questions, Peterson reported. But further study could help the medical profession. Although doctors treat individuals, not couples, information about one spouse's health could offer clues about the other's.
"People in relationships don't experience chronic health problems on their own. When a spouse comes in with a problem, the other spouse could be part of the cause or the solution," she wrote.
Even when spouses differ, one can have a positive effect on the other, NPR noted. Another team of researchers in Michigan this time at Michigan State University found that when one spouse's optimism increased, the other enjoyed better health, even if the other spouse's attitude was not quite as sunny.
The lead researcher, William Chopik, said optimists tend to have healthier lifestyles and they may be influencing their spouses to practice healthier habits, too.
"It's like finishing each other's sentences, but it's your muscles and cells that are operating in sync," said science writer Lindsay Peterson in a report for NPR.
The research, presented at the annual meeting of the Gerontological Society of America, came from an analysis of 1,568 married couples. Postdoctoral research fellow Shannon Mejia and colleagues at the University of Michigan in Ann Arbor found "striking similarities" in kidney function, cholesterol levels and grip strength among couples who had been together more than 50 years.
While one reason may be that people tend to marry people like themselves, this doesn't explain why people married for decades are more biologically similar than couples married for fewer than 20 years, Mejia said.
Their shared traits may be "something the couples co-created" over time, she said. (The Bible and Noel Paul Stookey famously put it another way: "the two shall be as one.")
The science behind it may be simple. Married couples share daily routines and environments, which may also explain why some long-married couples start to look alike. That phenomena has been attributed to our tendency to mimic each other's expressions, and married couples often share each others' emotions.
Of course, they also tend to eat similarly, which is why having an obese spouse doubles the chance that you will become obese, too.
Research into why couples grow to be physiologically similar has been limited, and there are still lots of unanswered questions, Peterson reported. But further study could help the medical profession. Although doctors treat individuals, not couples, information about one spouse's health could offer clues about the other's.
"People in relationships don't experience chronic health problems on their own. When a spouse comes in with a problem, the other spouse could be part of the cause or the solution," she wrote.
Even when spouses differ, one can have a positive effect on the other, NPR noted. Another team of researchers in Michigan this time at Michigan State University found that when one spouse's optimism increased, the other enjoyed better health, even if the other spouse's attitude was not quite as sunny.
The lead researcher, William Chopik, said optimists tend to have healthier lifestyles and they may be influencing their spouses to practice healthier habits, too.