The hearts of long-time couples synchronize when they're together

Married people with high relationship satisfaction had healthier blood pressure, lower stress levels and less depression than their unmarried counterparts or people in unhappy marriages.

Maija Kappler 3 minute read November 23, 2021
older couples heartrate

Older couples' heart rates can still sync up, according to a new study on relationships. (Getty)

Long-term relationships still have physiological effects into old age, according to a new study from the University of Illinois’ College of Agricultural, Consumer & Environmental Sciences that looked at the heart rates of romantic partners. Though the study had a small sample size, it revealed significant insights into the lives of people who had been partnered for a long period of time.

The findings, published in the Journal of Social and Personal Relationships, examined ten couples. They were all straight, married, between the ages of 64 and 88, and had been together for at least 14 years. (Some had been together for 65.) Over a two-week period, they wore FitBits and tracking devices, and researchers examined the couples’ heart rates and their physical proximity to one another when they were home. They also surveyed them daily about their health and the dynamics of their relationships.

Looking at each individual person’s heart rate when the couples were together, and then the two heart rates together, researchers found that when the couples were physically close to one another, their heart rates would synchronize in intricate, complicated ways. There was a “lead-lag” relation, they found: one heart rate would typically lead, and when the other caught up, that would lead while the first followed.

“This suggests a delicate balance,” the study’s lead author Brian Ogolsky told the university’s news outlet. “When one partner triggers the other partner, they start a unique couple-level dance that affects their physiology and their patterns throughout the day.”

Looking at physical evidence can sometimes be more accurate than asking questions, he added.

“Relationship researchers typically ask people how they’re doing and assume they can recall properly and give meaningful answers. But as couples age and have been together for a long time, they laugh when we ask them how satisfied or how committed they are. When they have been married for 30 or 40 years, they feel that indicates commitment in itself,” Ogolsky said. “We were looking for more objective ways to measure relationship dynamics, and we know that being around other people has psychological benefits. So, physical proximity seemed liked a strong candidate.”

Of course, synchronized heart rates aren’t always necessarily positive if the relationship isn’t a healthy one, he said.

“We’re not focusing on cause and effect, but on co-regulation, which happens when heart rates move in a synchronous pattern,” he said. “That is, when the partners are close, their heart rate patterns indicate an interaction that is collectively meaningful in some way.”

Previous studies have shown that bad relationships can actually have negative impacts on health: a large-scale British study from 2007 found that even after taking other health issues into consideration, people with “adverse” close relationships were 34 per cent more likely to develop heart problems. A 2016 study from the University of Michigan that specifically focused on older couples corroborated that finding.

But good relationships can have positive physical and psychological impacts. Married people with high relationship satisfaction had healthier blood pressure, lower stress levels and less depression than their unmarried counterparts or people in unhappy marriages. And according to a 2010 study, many of the benefits of marriage are just as effective if they apply to relationships with friends and family rather than romantic relationships.