Feb. 4, 2013 at 3:49 PM ET
Frigid winter weather may keep you huddled indoors all weekend, but here's a reason to venture out and be social: Loneliness wrecks your immune system, according to a study from The Ohio State University.
Researchers performed two studies to assess how feeling lonely--as opposed to actually having very few friends--squashed your health. In one, the loneliest people had the highest amounts of antibodies for two cold-like viruses that live on harmlessly in your body after you get well--a sign of a weakened immune system. (Strengthen your immunity with 5 Fruits That Fight the Flu.)
In the second study, the researchers found that when 134 people were faced with sudden stress (by having only 10 minutes to prepare to give a 5-minute speech), the loneliest ones experienced a much bigger spike in markers of inflammation as a result of the stress than people who felt less alone.
Scientists are still trying to pin down exactly how the psychological state of feeling unloved can affect your physical well-being. But it's likely because the isolation piles on yet another misery in your already stressful life. "Many of the links between stress and physiological changes, such as immune function, should also apply to loneliness," says study author Lisa Jaremka, Ph.D., a post-doctoral fellow at Ohio State. (Your buddies do more for your health than boost your immunity. Find out Why Every Guy Needs a Poker Night.)
To make matters worse, inflammation and a compromised immune system aren't the only health problems caused by flying through life solo. Here are five more reasons why you should buddy up:
1. People with more friends live longer.
In an Australian study of 1,477 retirees, the ones with the biggest real-life social networks, including friends and family, were 22 percent less likely to die within 10 years than those with the fewest buddies. The researchers suggested a variety of reasons to explain why, including better access to medical care and the financial resources to pay for it, and more influence to reduce smoking and alcohol consumption and increase exercise.
2. A friendly chat eases pain.
Even a quick conversation can help you better handle pain, according to a study at the University of Virginia. Researchers had 202 strangers pair up and chat for 8 minutes, asking them each to fill out a questionnaire identifying traits in the other person. Then the researchers gave half the partners fake responses, manipulating them into feeling misunderstood by the person they spoke with. The results: Those who felt like they connected with their partner were better able to withstand pain immediately afterward--in the form of holding their hand in ice cold water until they couldn't take it--than people who felt misunderstood.
3. Marriage helps you survive heart surgery.
When researchers at the University of Rochester tracked 173 men who had heart surgery, 86 percent of the happily married guys were still alive 15 years later, compared to just 36 percent of unmarried guys. Even men who said they were unhappy with their marriages lived longer--60 percent of those husbands survived. It's likely because a spouse helps you stick to the healthy lifestyle changes, such as eating better and going for daily walks. And maybe wives taking away cheeseburgers could explain why some of the men seemed so disgruntled. (How strong is your marriage? Answer these 5 questions to find out.)
4. Divorce leads to heart disease and diabetes.
Not only are divorces 20 percent more likely to have chronic health problems, according to a study at Johns Hopkins University, but even the ones who remarried only cut that risk down by about 8 percent. Add it all up, and divorced men had a 31 percent increased risk of dying early in a separate study from the University of Arizona. Blame the stress of divorce, which not only places extra strain on your cardiovascular system, but also results in many people sleeping less, skipping exercise, and eating poorly in the years after they split--all factors that lead to heart problems and weight gain.
5. Internet friends help you get ripped.
Maybe you don't have to leave the house to be healthier. A study at the Kaiser Permanente Center for Health Research in Portland found that when people who had lost an average of 19 pounds participated in an online weight loss and fitness website, they were able to hang on to 44 percent of the initial weight lost. The website studied included widgets to track weight-loss goals and the amount of exercise performed, and a chat forum. There's no shortage of well-designed and popular websites to help you find online workout pals: Check out Fitocracy, Nike+, and the Men's Health Belly Off! Club.