Do friends help you live longer? What the research says

It’s 9pm, you’re halfway through something for work, and your friend’s name lights up your phone. You let it ring out and tell yourself you’ll call back at the weekend. Most of us file friendship under “nice to have”: lovely, important even, but not exactly a health decision.

Some of the biggest studies in health research suggest that file is in the wrong drawer. How connected you are seems to sit in the same league as the habits we already take seriously, like not smoking and staying active. Here’s what the evidence shows, what it doesn’t, and what to do with it.

Do people with friends live longer?

In 2010, psychologist Julianne Holt-Lunstad of Brigham Young University and her colleagues pooled 148 studies covering 308,849 people. Each study had measured people’s social relationships and then followed them for years to see who was still alive.

The pattern was clear. People with stronger social relationships had about 50% higher odds of survival over the course of the studies. That doesn’t mean they lived 50% longer. It means that, at any given follow-up, they were noticeably more likely to still be alive. The link held across age, sex, initial health status and cause of death.

It was strongest for the richest measures of social life, the ones that looked at how woven into other people’s lives someone was rather than just whether they lived alone. On those, the odds of survival were almost double.

To give that some scale, the authors compared it with other risks. The effect of strong relationships was comparable to quitting smoking, and bigger than the effect of risks such as obesity and physical inactivity. That doesn’t make a friend a medical treatment. It does put friendship on the list of things worth taking seriously for your health.

How bad is loneliness for your health?

In 2015, the same team looked at the problem from the other side. They pooled 70 studies covering more than 3.4 million people and separated three things that often get lumped together:

• Social isolation: having few contacts. Linked to a 29% higher likelihood of dying during the study periods.
• Loneliness: the feeling of being disconnected, whoever is around you. Linked to a 26% higher likelihood.
• Living alone: linked to a 32% higher likelihood.

These figures come from studies that statistically controlled for other factors, such as existing health conditions. Two details are easy to miss. First, the feeling mattered as well as the facts: you can be surrounded by people and still lonely, and that showed up in the data. Second, the links were stronger in samples where the average age was under 65. Disconnection isn’t only something that happens to older people. It reaches into the busy middle of life, when many of us assume we’re too occupied to be affected.

Why would friendship affect your body?

A link between friends and lifespan raises an obvious question: how does something social get under your skin? One of the clearest clues comes from stress.

In a 2003 experiment, Markus Heinrichs and colleagues put 37 healthy men through a standard lab stress test, which involves giving a speech and doing mental arithmetic in front of an evaluating panel. Some had their best friend with them while they prepared. Some were given a nasal spray of oxytocin, a hormone involved in bonding, and some a placebo. Support from a friend lowered levels of the stress hormone cortisol. The men who had both their friend and oxytocin had the lowest cortisol of all, and felt calmer and less anxious.

It’s a small study, all men, in a lab, so treat it as a clue rather than a final answer. But it fits a wider picture. In a 2015 review, Camelia Hostinar and Megan Gunnar described how support from close people acts as a buffer against stress, particularly in childhood. They pointed to two possible pathways in the brain: oxytocin activity in the hypothalamus, and areas of the prefrontal cortex involved in self-regulation. In plain English, having someone in your corner seems to change how hard your body reacts when life gets tough, not just how you feel about it.

Does belonging to a group count, or only close friends?

Close friends aren’t the only kind of connection that seems to matter. In a 2017 review, Niklas Steffens and colleagues pooled 58 samples covering 19,799 people, all looking at workplaces and organisations. People who identified more strongly with their team or organisation, who felt part of a genuine “we”, tended to report better health and wellbeing.

The link was moderate, stronger for wellbeing than for stress, and stronger for mental than physical health. It was also stronger when the sense of identity was shared across the group. A team where everyone feels they belong seems to look after people better than one where only a few do.

What this research can’t tell you

Almost all of this is observational. Researchers can’t randomly assign people to have friends for twenty years, so it’s possible that people who are already healthier find it easier to stay social. The studies try to control for this, and the 2010 result held regardless of people’s health when they joined. Still, these are strong associations, not guarantees, and no one can promise that a phone call adds a year to your life.

It also isn’t a reason to feel guilty. If you’re short on close friends right now, that’s common, and it’s changeable. The point isn’t to count your friends. It’s to treat time with people as something that matters, rather than the first thing to go when you’re busy. You can read more about the evidence on our research page.

How to build friendships that last

The studies above measured connection over years, not one good evening. So the practical move is to build things that repeat:

1. Put one recurring thing in the calendar. A Sunday walk, a Thursday call, a monthly dinner. Same people, same slot. Repetition does the heavy lifting.
2. Revive one dormant group chat. The one that only wakes up for birthdays. Suggest an actual plan with a date.
3. Call back within 48 hours. That 9pm call you ignored? Return it before the weekend. Small follow-through is what keeps a friendship alive.
4. Go one question deeper. Swap “How’s work?” for “What’s been on your mind lately?” Feeling known is the opposite of loneliness.
5. Join something you’ll show up to weekly. A team, a class, a volunteering shift. It gives you a group to belong to and the same faces every week.
6. Check the feeling, not just the numbers. Ask yourself who you could call at 2am. If the answer is nobody, that’s the gap to work on first.

Where Everconnected fits

If you’d like to try this with someone new, Everconnected matches you with people who share your values and interests, for one-to-one conversations by voice. It’s free to join: create an account at app.everconnected.com, or get the app from the App Store or Google Play.

Questions people ask

Sources

1. Holt-Lunstad, J., Smith, T. B., & Layton, J. B. (2010). Social relationships and mortality risk: A meta-analytic review. PLoS Medicine, 7(7), e1000316. doi.org/10.1371/journal.pmed.1000316
2. Holt-Lunstad, J., Smith, T. B., Baker, M., Harris, T., & Stephenson, D. (2015). Loneliness and social isolation as risk factors for mortality: A meta-analytic review. Perspectives on Psychological Science, 10(2), 227-237. doi.org/10.1177/1745691614568352
3. Heinrichs, M., Baumgartner, T., Kirschbaum, C., & Ehlert, U. (2003). Social support and oxytocin interact to suppress cortisol and subjective responses to psychosocial stress. Biological Psychiatry, 54(12), 1389-1398. doi.org/10.1016/S0006-3223(03)00465-7
4. Hostinar, C. E., & Gunnar, M. R. (2015). Social support can buffer against stress and shape brain activity. AJOB Neuroscience, 6(3), 34-42. doi.org/10.1080/21507740.2015.1047054
5. Steffens, N. K., Haslam, S. A., Schuh, S. C., Jetten, J., & van Dick, R. (2017). A meta-analytic review of social identification and health in organizational contexts. Personality and Social Psychology Review, 21(4), 303-335. doi.org/10.1177/1088868316656701