Men and women are more likely to quit smoking and work out more if their partners also start to behave in a more healthful way, research indicates.

A growing body of evidence shows birds of a feather do flock together when it comes to eating, smoking and physical activity behaviours, particularly for spouses.  

Now scientists have tapped into data from the English Longitudinal Study of Aging, a long-term study of people 50 and older, to test whether one person's "health behaviour" change can influence a partner.

Sarah Jackson of University College London and her team measured the heights and weights every two years of 3,733 couples who stayed together from 2002 to 2013. Participants also filled in questionnaires about their smoking and physical activity levels.

They found one partner was more likely to make a positive change if their partner made the change as well.

Couples' fitness

Leonard Collier and Martha Binks say they provide comic relief to their couples' fitness class in Toronto. Research suggests you can get more motivated to lose weight or quit smoking when your partner motivates you. (CBC)

For example, for women who smoked, the researchers estimated half quit if their partner butted out at the same time. For those with a partner who were already non-smokers, 17 per cent succeeded. Women whose partners continued to smoke fared worst at quitting at eight per cent.

"It seems like doing the same thing together is more effective than even having a good role [model] in their partner," said study co-author Andrew Steptoe of University College London.

"They're not necessarily helping you, going through the same sort of problems, the same difficulties of getting up and getting active when the weather is bad and things like that, compared with someone who has a partner who's trying to do it at the same time as them."

The researchers offered their views about how one person's behaviour can affect a partner.

  • Partners may decide to make a change for the better together.
  • One partner spurs on the other.
  • It happens subconsciously as one loses weight and the other eats the same lower-calorie meals.

To promote public health goals, Steptoe recommends taking the social context of someone's family members into account when trying to persuade and encourage healthier choices.

The researchers also ran models to compare the odds of having a consistently healthy or newly healthy partner, to determine if husbands were affected more by their wives or vice versa. It turned out men and women were similar.

Working out with partner 'more fun'

For smoking, weight loss and physical activity, positive changes were more likely when the partner made the switch, than if the partner were consistently healthy.

Take Leonard Collier and Martha Binks, who attend a couple's fitness class in Toronto. 

Leonard Collier was surprised by the researchers' findings, but said it makes sense.

"I needed somebody to encourage me to come and do this sort of thing," Collier said.

"It’s more fun to come with him," Binks agreed.

Martha Binks signed them up for the class as a Valentine's Day gift nearly four years ago.

"We sometimes consider ourselves comedy relief for the rest of the class," Collier said with a laugh.

Meanwhile, smoking cessation research cited by the British Columbia Centre for Excellence for Women’s Health — research used to encourage women who are pregnant or recently gave birth — indicates people who live with a partner or family members who smoke find it harder to quit.

In contrast, having a partner who is supportive can help someone give up smoking. For example, if a smoker tends to light up after supper while watching television, his or her partner could encourage going for walk instead.

Anyone who supports the healthy behaviour, such as a friend or colleague who joins in for a run or swim, could help boost success rates, said Dr. Julie Sharp of Cancer Research UK. The agency supported one of the authors.

The study was funded by the U.S. National Institute on Aging and a group of government departments in the United Kingdom.