With no offense to my husband or the rest of my family, I really don’t think that I could make it through the day — much less have weathered all the ups and downs of the last three decades or so — without my friends.

Whether it’s comparing child-rearing notes with Puffin, gossiping over coffee with Hannah and Maggie, hashing out long-term goals with my power-walk partner Sara, parsing last night’s festivities with Stacie or commiserating with Janet about a major setback, each of these women helps keep me balanced and sane.

My inner circle has been there for me in countless ways over the years, and I’ve always tried to reciprocate with as much time, support and love as possible.

Not that I ever need an excuse for a girls’ night out, but research suggests that good friends may actually be great medicine: Strong social ties may help stave off memory loss as you age; reduce stress; boost immunity; help you lose weight and keep it off; and buffer against depression, among other health benefits. There’s also a strong longevity link, says Carl Latkin, a professor of social and behavioral sciences at the Johns Hopkins Bloomberg School of Public Health: “If you have supportive relationships, you’re going to live longer.”

In fact, a 2010 review of nearly 150 studies that was published in PLoS Medicine found that people with strong social ties had a 50 percent better chance of survival, regardless of age, sex, health status and cause of death, than those with weaker ties. This conclusion was based on information about more than 300,000 individuals who were followed for an average of 7.5 years. According to the researchers, the health risk of having few connections was akin to smoking 15 cigarettes a day, and more dangerous than being obese or not exercising in terms of shaving years off your life.

And numerous studies have shown that friends may affect your health even more than family members: The 2005 Australian Longitudinal Study of Aging found that close relationships with children and other relatives had little impact on longevity, while people with the most friends tended to outlive those with the fewest by 22 percent.

Close comrades seem to be a valuable advantage when it comes to battling specific medical conditions such as heart disease and obesity. A study of 2,230 breast cancer patients in China published in the Journal of Clinical Oncology last month found that social quality of life – including the strength of friendships — was the most important predictor of both cancer recurrence and survival. “It’s very exciting, because we believe social quality of life is modifiable — it’s something that we can change,” says the study’s lead author, Meira Epplein, an assistant professor at the Vanderbilt University School of Medicine.

Still, experts stress that it remains unclear exactly why the buddy system seems to convey benefits. “If you have a larger social network, is it material resources like those people taking you to the doctor and making sure you take your medication? Does that make a difference?” asks Latkin. “Or does having a confidant result in some emotional or psychological process that might increase well-being and reduce depression? In other words, are friends protecting you from bad things or promoting good things?”

Much has been made of the remarkable power and influence of female friendships in particular. (See: “Fried Green Tomatoes, ” “Thelma and Louise,” “Divine Secrets of the Ya-Ya Sisterhood.”) But both sexes seem to benefit by having close confidants, says Latkin. “It used to be thought that men had larger social networks while women had more intimate networks, but . . . that’s not necessarily a tried-and-true statement anymore,” he says. If men manage to gather similar emotion support around them, they’ll likely experience the same benefits.

A 1993 study of 736 middle-aged Swedish men, for instance, makes that point: It found that having a strong social network seemed to significantly decrease the risk of heart attack and fatal coronary heart disease.

Even so, as anyone with a wide social network can probably tell you, chums aren’t always a positive thing. “There are downsides … like if you have a lot of network members who are requesting support and demanding resources from you, which can be highly stressful,” says Latkin. He adds that having people in your friendship network with whom you have conflicts or whom you can’t stand tends to overcome the positive effects of true friendship within that group. And sometimes the behavior of good pals can cause problems: A 2007 study suggested that if your friends gain too much weight, you’re more likely to do so, too.

For the Internet generation, it’s also worth noting that “it’s both the density and quality of social relationships that make a real difference in people’s lives,” says psychologist David Shern, president and chief executive of Mental Health America, a nonprofit advocacy organization based in Alexandria.

AnyBODY illustration for 3/15/11 (Becky Heavner/BECKY HEAVNER)

“Simply having 1,000 friends on Facebook is much less important than having a few friends with whom have a very high-quality, mutually supportive relationship with integrity — meaning that you can count on people to be straight with you, and ... to rely on when you find yourself in need.”

But why wait until you’re in need, given how beneficial a little friendly face time can be? I, for one, am planning my next girls’ night out right now.