Sometimes it’s near impossible to take that first step toward a healthier lifestyle. For one, the first week after a person quits smoking is fraught with nicotine withdrawal symptoms, like irritability, trouble sleeping, and a cloudy mind. Many people fear that initial stage, and there are now support systems online and in person that help people get through. A person’s partner, however, may be the best influence in stoking a healthier lifestyle, according to a new study.

Most people spend a lot of time with their partners, making it easy to influence one another into picking up certain habits. These habits can sometimes be bad, but they don’t always have to be. Studies have shown that people who exercise with a friend tend to have more fun with their workout, and they’ll also push themselves harder if the other person is more fit. If this is what happens when we workout with friends, imagine what can happen when working out, or adopting a healthier lifestyle, with a partner.

Researchers from University College London in the UK looked at data on 3,722 couples, either married or cohabitating, who were all over age 50 and participating in the English Longitudinal Study on Ageing. They found that people were more likely to quit smoking, exercise, or lose weight if their partner also worked toward those same goals. For example, they found that 50 percent of women were able to quit smoking if they had a partner who had also quit. In comparison, 17 percent of women whose partners were nonsmokers were able to quit, while eight percent of women whose partners smoked quit.

“Making lifestyle changes can make a huge difference to our health and cancer risk, and this study shows that when couples make those changes together they are more likely to be successful,” said Dr. Julie Sharp, head of health information at Cancer Research UK, which funded the study, in a press release. “Getting some support can help people take up good habits.”

Adopting better habits not only reduces these peoples’ risks of preventable diseases, such as type 2 diabetes, heart disease, and cancer — which can all develop from smoking, and a lack of exercise and a healthy diet — but it can also strengthen the relationship. Exercising together, for example, pushes a couple to challenge themselves more with their workout. This stimulates physiological arousal, such as sweaty hands and a fast pulse, which mirror the same physiological activities as romantic attraction. On top of that, it also gives a couple one more thing to do together.

“When a couple works out together, the actual exercise itself can physically and emotionally have a positive impact,” said marriage and relationship psychotherapist Dr. Jane Greer, according to The Huffington Post. "Both partners come away with feelings of synchronicity, cooperative spirit, and shared passion. Then you throw in some spicy endorphins and it can be a real power trip for the relationship."

Source: Jackson S, Wardle J, et al. Jama Internal Medicine. 2015.