
If you've ever been in a relationship, you've sure had at least one moment when you've wondered if it's worth it. Everyone does. The data from myriad studies suggests, from a health perspective, they're surely worth a shot. A 2010 study of more than 309,000 people found that those without strong relationships had a 50% higher risk of dying from any cause—a risk similar to smoking 15 cigarettes a day. But other studies have shown that picking a mate doesn't automatically make you healthier, and in fact, certain relationship behaviors can wreak havoc on your body. Here are 10 surprising ways your relationships may be affecting your health.
They Can Make Your Wounds Heal—Or Not

Turns out a conflict-filled relationship can literally reopen wounds. A study at Ohio State University found that married couples who argued had a slower rate of physical wound healing than couples who were more encouraging and supportive. "Wounds on the hostile couples healed at only 60% of the rate of couples considered to have low hostility," one of the researchers said. The reason? Marital arguments created an overwhelming release of an immune chemical called interleukin-6 (IL-6), a cytokine, which actually slowed the healing of cuts on the skin.
They Give You a Healthier Gut

"Our relationships can profoundly impact our gut health. We know that there is a direct link between our gut and our brain, and if we are stressed due to poor interactions within our relationship, this can lead to negative implications on our gut," says Kara Landau, RD, a New York City-based registered dietitian. "Similarly, when we have good relationships and are feeling calm, this can positively impact our gut health." Studies have shown that people in close marital relationships have greater diversity in gut bacteria —a good thing—than people who live alone or without close ties.
They Can Impact Your Blood Pressure

"The marriage advantage" is the oft-cited phenomenon that married people live healthier and about four to seven years longer than single people. "Yet, as most blanket statements go, there is an asterisk with that," says Alexandra Davis of Ryan and Alex Duo Life, a wellness site for couples. "A study conducted by Brigham Young University found 77% of married couples had ambivalent marriages, a mix of some good and some not-good aspects. The unpredictability led to higher blood pressure."
They Can Make You Happy—And Fat

According to a study at Southern Methodist University in Dallas, newlyweds who are satisfied with their marriages are more likely to gain weight in a marriage's early years than those who aren't satisfied. "These findings challenge the idea that quality relationships always benefit health, suggesting instead that spouses in satisfying relationships relax their efforts to maintain their weight because they are no longer motivated to attract a mate," the researchers said.
The Rx: Those researchers said it best: "Interventions to prevent weight gain in early marriage may benefit from encouraging spouses to think about their weight in terms of health rather than appearance."
They Can Literally Break Your Heart

A survey of 9,000 men and women in the British Civil Service found that people who reported "adverse" close relationships had a 34% increased risk of developing heart disease, even after removing factors like weight and level of social support. Chronic stress causes wear and tear on the body, especially the heart.
Being Lonely Can Cause Inflammation

Chronic inflammation in the body is linked to a variety of serious illnesses, including heart disease, cancer and dementia. A review of 20 years of research found that lonely people had higher levels of C-reactive protein, a key marker of inflammation, along with higher blood pressure. Loneliness causes chronic stress, which can stoke inflammation.
They Make It Easier to Change Bad Habits

One positive aspect of relationships is that they help you stay accountable for making positive changes. Researchers at University College London found that in a group of women who tried to quit smoking, 50 percent succeeded if their partner quit at the same time. Meanwhile, women with already non-smoking partners were only 17 percent successful, and only 8 percent of women whose partners were smokers kicked the habit.
They Could Raise Your Diabetes Risk

Partners can reinforce each other's bad habits, too. A study at the McGill University Health Center in Canada found that people whose partners have Type 2 diabetes have a 26 percent higher risk of developing the disease. The major risk factors for developing diabetes: Being overweight, sedentary and eating a poor diet high in added sugar and processed foods.
They Lower Dementia Risk

A 2018 study of 12,000 people by the University of Florida College of Medicine found that loneliness can increase your risk of dementia by a whopping 40 percent. People who reported feeling lonely were more likely to develop symptoms of dementia over the following decade, and the risk remained even after adjusting for other risk factors like diabetes, hypertension, depression, smoking and a sedentary lifestyle.
They Affect Recovery

When you're sick, the quality of your romantic relationship may affect how ill you feel and how quickly you get better. That was the finding of a 2009 study published in the journal Cancer: Breast cancer survivors experiencing relationship distress were more stressed overall, less functional and less complaint with their treatment than those in stable relationships, slowing their recovery.
And to live your happiest and healthiest life, don't miss these 101 Unhealthiest Habits on the Planet.