Whether you are in a new relationship or a long-term one, newlyweds or celebrating your golden wedding anniversary, a same-sex couple or of the opposite sex, the time spent with your partner can influence your health outcomes.

Having a healthy relationship is not only rewarding, but it also significantly shapes our long-term health in a similar way to getting a good night’s sleep, eating healthfully, and not smoking. Studies have shown, time and time again, that people who are in satisfying relationships feel happier, have fewer problems with health, and live longer.

On the flip side, having unhealthy connections or a lack of social ties is linked to depression, cognitive decline, and an increased risk of premature death.

Here are some of the beneficial and detrimental effects that your relationship could have on your well-being.

Positive effects of a partner on health

Pain relief

A partner’s touch has been found to relieve pain in women.

It is well known that people subconsciously synchronize their footsteps when they walk together or mirror a friend’s posture during a conversation.

Investigators from the University of Colorado, Boulder and the University of Haifa in Israel have now discovered that when heterosexual lovers touch when the woman is in pain, couples’ heart rates and respiratory patterns synchronize and the woman’s pain dissipates.

These findings add to a growing body of evidence on “interpersonal synchronization,” a phenomenon in which people begin to physiologically mirror those that they spend time with. “The more empathic the partner and the stronger the analgesic effect, the higher the synchronization between the two when they are touching,” explains lead author Pavel Goldstein, a postdoctoral pain researcher at the University of Colorado, Boulder.

Help achieve healthy goals

Two heads are better than one when it comes to taking up healthy habits. Funded by Cancer Research UK, the British Heart Foundation, and the National Institute on Aging, scientists at University College London (UCL) in the United Kingdom revealed that if you want to swap bad habits for good, then you would be more successful if your partner also makes those changes.

Among women who smoked, the researchers found that 50 percent succeeded in quitting smokingif their partner gave up at the same time, compared with 17 percent whose partners were non-smokers already, and just 8 percent whose partners smoked regularly.

“Unhealthy lifestyles are a leading cause of death from chronic disease worldwide,” says study author Prof. Jane Wardle, director of Cancer Research UK’s Health Behaviour Research Centre at UCL. “The key lifestyle risks are smoking, excess weight, physical inactivity, poor diet, and alcohol consumption. Swapping bad habits for good ones can reduce the risk of disease, including cancer.”

Improve fitness

Echoing these findings, the Johns Hopkins Bloomberg School of Public Health in Baltimore, MD, conducted research finding that improving your fitness could also improve the fitness of your spouse.

Couples were asked about their physical activity levels at two medical visits conducted around 6 years apart. On the first visit, if a wife met the recommended guidelines for physical activity, her husband was 70 percent more likely to also reach those targets at subsequent visits than those whose wives were less active.

Conversely, when a husband met recommended activity levels, his wife was 40 percent more likely to also achieve these levels at follow-up visits.

When it comes to physical fitness, the best peer pressure to get moving could be coming from the person who sits across from you at the breakfast table,” says co-author Laura Cobb, a doctoral student at Johns Hopkins Bloomberg School of Public Health. “There’s an epidemic of people in this country who don’t get enough exercise, and we should harness the power of the couple to ensure people are getting a healthy amount of physical activity.”

Alter microbiome

Microbial exchange with your partner can occur simply from walking on the same bathroom floor.

Researchers from the University of Waterloo in Canada found that couples who live together influence the microbiome – that is, the community of bacteria and other microbes – on each other’s skin.

Commonalities between couples’ skin microbiome were strong enough that computer algorithms could detect couples that cohabit with an accuracy of 86 percent.

Skin regions that were the most similar between partners were on the couples’ feet. “In hindsight, it makes sense,” says Prof. Josh Neufeld, of the Faculty of Science in the Department of Biology at the University of Waterloo. “You shower and walk on the same floor barefoot. This process likely serves as a form of microbial exchange with your partner, and also with your home itself.”

Improve physical and mental health

While analyzing whether or not relationships are good for your health, David and John Gallacher, from Cardiff University in the U.K., confirmed that long-term, committed relationships are good for physical and psychological health, and that these benefits increase over time.

On average, individuals who are married live longer; women have better mental health when they are in committed relationships, while men have better physical health when in a committed relationship. The study authors say, “On balance it probably is worth making the effort.”

Decrease risk of health conditions

Studies have shown that partners can also affect each other’s risk and development of disease.

Persistent nagging from your partner could slow down diabetes progression.

For example, a study by Michigan State University (MSU) in East Lansing deduced that for men who are in an unhappy marriage, the development of diabetes is slower and treatment is more successful once they are diagnosed.

The researchers said that wives who continuously regulate their husband’s health behaviors and who are seen as annoying and provoking hostility and emotional distress in the husbands could explain this finding.

The study challenges the traditional assumption that negative marital quality is always detrimental to health,” says lead investigator Hui Liu, an associate professor of sociology at MSU. “It also encourages family scholars to distinguish different sources and types of marital quality. Sometimes, nagging is caring.”

Researchers from the University of Michigan have also determined that having an optimistic spouse predicted fewer chronic illnesses and better mobility over time.

A growing body of research shows that the people in our social networks can have a profound influence on our health and well-being,” says lead study author Eric Kim, a doctoral student in the University of Michigan’s Department of Psychology. “This is the first study to show that someone else’s optimism could be impacting your own health.”

In other research, people who are happily wed are more than three times as likely to be alive 15 years after coronary bypass surgery as their unmarried counterparts. Married people also are less likely to have cardiovascular problems than individuals who are single, divorced, or widowed.

Adverse effects of a partner on health

Intensify pain

In contrast to the research that showed a partner’s touch decreases pain, a study by King’s College London in the U.K. found that being in the company of your partner could make pain worse.

The researchers found that the more avoidant of closeness women were in their relationships, the more pain they experienced when given a laser pulse on their finger.

Research led by the University of Edinburgh in the U.K. also found a connection between partners and pain. The team found that partners of individuals with depression have an increased risk of experiencing chronic pain.

The researchers’ analysis showed that depression and chronic pain share common causes. Some of these causes are genetic while others stem from the environment shared by the partners.

Derail your diet

Dieting with your partner could end up derailing your weight loss plans.

Dieting with your partner may seem to be a good idea, but research has indicated that among romantic couples, the more successful one partner is at restricting their diet and eating more healthfully, the less confident the other partner becomes at controlling their food portions.

When people strive to reach a goal, being close (in this case, romantically) with someone who is successfully reaching the same goal can make the other partner less confident in their own efforts to reach the goal,” explains Jennifer Jill Harman, an associate professor at Colorado State University in Fort Collins.

Facilitate weight gain

Marriage has been positively correlated with weight gain among couples. For example, lead researcher Andrea L. Meltzer – an assistant professor at Southern Methodist University in Dallas, TX – and collaborators unveiled that newlyweds who are satisfied with their marriage are more likely to gain weight in the early years of marriage than those who are unsatisfied.

“On average, spouses who were more satisfied with their marriage were less likely to consider leaving their marriage, and they gained more weight over time,” states Prof. Meltzer. “In contrast, couples who were less satisfied in their relationship tended to gain less weight over time.

Other research by the University of Bath’s School of Management in the U.K. showed that marriage makes men gain weight and that fatherhood exacerbates the problem further.

Increase risk of health conditions

In contrast with research signalling that your significant other can decrease your risk of certain health conditions, other studies show the reverse.

For example, the McGill University Health Centre in Canada has suggested that if someone has type 2 diabetes, their partner has a 26 percent increased risk of also developing the condition.

While spouses are not related biologically, they share the same environment, social habits, and eating and exercising patterns – all of which are factors that alter the risk of developing type 2 diabetes.

“When we talk about family history of type 2 diabetes, we generally assume that the risk increase that clusters in families results from genetic factors. What our analyses demonstrate is that risk is shared by spouses,” says senior study author Kaberi Dasgupta, of the Research Institute at McGill University.

Giving your spouse the silent treatment increases your risk of back pain and stiff muscles.

Furthermore, the way that you react to disagreements and argue with your partner could predict health problems later in life. The University of California, Berkeley, and Northwestern University in Evanston, IL, revealed that fits of rage during marital spats can predict cardiovascular problems, and shutting down and giving the silent treatment raises the risk of a bad back or stiff muscles.

“Conflict happens in every marriage, but people deal with it in different ways. Some of us explode with anger; some of us shut down,” says lead study author Claudia Haase, an assistant professor of human development and social policy at Northwestern University. “Our study shows that these different emotional behaviours can predict the development of different health problems in the long run.”

Research has also indicated that individuals may unintentionally worsen their partner’s insomnia. Moreover, other research found that inflammation markers rise in tired partners who argue.

Additionally, in older adults, researchers learned that the frailer an individual – a condition that affects around 10 percent of those aged 65 and over – the more likely it is that they will become depressed. Equally, the more depressed an older person is, the frailer they will become.

What is more, people married to frail spouses had an increased risk of becoming frail themselves, and those married to a depressed partner were also more likely to become depressed.

And interestingly, health changes influenced by a romantic partner do not necessarily end when they pass away.

Kyle Bourassa, a psychology doctoral student at the University of Arizona in Tucson, and colleagues found that couples’ qualities of life are linked even when one partner dies.

The people we care about continue to influence our quality of life even when they are gone. We found that a person’s quality of life is as interwoven with and dependent on their deceased spouse’s earlier quality of life as it is with a person they may see every day.

Kyle Bourassa

Bourassa says that even though we have lost the people we love, they remain with us. The research highlights how important relationships are for our health and well-being. However, he does say that the findings are cut both ways. “If a participant’s quality of life was low prior to his or her death, then this could take a negative toll on the partner’s later quality of life as well.”