Trust Me, I'm a Behavioural Scientist—Friendships Are One of the Most Powerful Yet Overlooked Health Tools

I’ve been thinking a lot about friendship lately. Specifically, the women I couldn’t imagine my life without, and how embarrassingly easy it has become to go weeks, sometimes months, without properly seeing them.

We are, after all, very busy people. There are jobs, partners, children, ageing parents, life admin and approximately 38 WhatsApp conversations we are already failing to keep up with. Friendship can start to feel like another thing on the list. Something we’ll get to when everything else is done.

Except, it turns out, friendship might not be a nice-to-have at all. It may be one of the pillars of staying well; a biological necessity.

One look at the research, and that post-friendship exhale starts to make perfect sense. A 2010 meta-analysis of 148 studies found that people with strong relationships had a 50% greater likelihood of survival than those with weaker social connections. The researchers also found that the mortality risk associated with social isolation was comparable to - and in some cases greater than - risk factors such as obesity, physical inactivity and heavy alcohol consumption. In other words, your friends are, quite literally, either adding years to your life or taking them away.

And for women, the story gets even more interesting. Because friendship doesn’t just make us feel better - it can change what's happening inside our bodies. Neuroscience research suggests that close friends can begin to synchronise with one another - their brains, emotions and even psychological responses falling into step. In a sense, spending time with someone we trust creates a shared version of the world: one that can feel safer, more familiar, and crucially, easier to navigate.

So that feeling after a two-hour catch-up and you walk home lighter than you arrived; it turns out - it isn’t just in your head - your body has been asking for her all along.

Hooked? Before you rush off to text one of your 38 unopened WhatsApps with “I’m so sorry for the slow reply”, let me throw one more thing into the mix: if female friendship is so deeply wired into us, what happens when we stop making time for it? Why, despite knowing how much we need one another, do so many of us push our closest friendships to the bottom of the list? Experts, come forward. It’s time to find out what we’re risking when we do. Keen to read more? See how one Health Writer got on treating friendship as a wellness habit, and scroll through expert-backed healthy ageing habits and Blue Zone tips while you're here.

Why a Behavioural Scientist Thinks Friendships Are One of the Most Powerful Health Tools

The Biological Reason For Needing Friendships

“Friendships can actually influence our neurochemistry and change how we perceive the world, experience stress, how threatening the world feels, and even how demanding a task appears,” explains behavioural scientist Ghazal Moenie.

It is a deceptively big claim for something we tend to think of as fairly ordinary: a quick coffee, walking home together, sitting on the sofa talking absolutely nothing. But there is growing evidence that the presence - and quality - of our closest relationships can change the way our bodies respond to the world around us. Research has found that people had lower blood pressure and heart rate reactivity when facing stress with a supportive friend than when alone. TDLR: friendship can really alter how difficult we perceive life to be.

The implication is not that friendship magically takes all our stress away. Rather, close relationships can act as a buffer: making the same challenge feel less threatening, and perhaps more manageable.

For women, there may be an additional layer. 26 years ago, researchers at UCLA proposed the idea of “tend-and-befriend” - essentially, that women may respond to stress in a slightly different way than the familiar fight-or-flight response. When something goes wrong, our instinct isn’t necessarily to run or retreat. We might call a friend. We might gather the women around us. We might talk it through, look after someone else, or simply need to be near people who make us feel safe.

Naturally, there’s biology behind that instinct, too. The research suggested that oxytocin - sometimes referred to as the “bonding hormone” - plays a role in encouraging social connection and helping regulate the body’s stress response. “Oestrogen can enhance the effects of oxytocin, which may help explain why this response is particularly relevant to women,” says Moeni.

Evolutionarily speaking, the theory goes, women were encouraged to both “tend” - protect and care for offspring - and “befriend": make those social connections that could offer all of the above.

It gives a rather beautiful biological explanation for something most of us already know: the friend we call when everything feels too much may not be distracting us from the stress; she may be a part of how our bodies know to carry it.

The hidden health cost of feeling disconnected

I can’t be the only one who feels heavily lost - emphasis on the heavy - when I don’t spend quality time with my girlfriends. Nothing light; I’m talking sitting down, opposite one another, discussing the woes of the world. I know that once I’ve had this, I feel like I’ve been pieced back together. The more I researched, the more one question kept cropping up: what happens to our health when we don’t have connection?

​If we are, as research suggests, biologically wired for closeness, the absence of it matters significantly. “There is lots of research now showing that being lonely is linked to poor mental health, high anxiety and high stress,” explains neuroscientist Antonia Hamilton. “In older people,” she says, “loneliness is also associated with dementia and heart disease.”

​And the physical effects appear to run deeper than feeling low or lonely. A 2024 systematic review of 24 studies, representing almost 300,000 adults, found that social isolation was linked with higher levels of inflammation, frailty and cognitive decline, as well as disrupted sleep and a higher risk of death.

​But Hamilton is keen to point out: “Connection can be protective, too. For young people with mild depression or anxiety, she says, joining a structured social group once a week for at least six weeks can have benefits comparable to antidepressants. It doesn’t much matter whether that’s a choir, walking group, dance class or book club. The important thing is the regularity of the connection.”

​Time to welcome a mindset change? Connection isn’t something we simply have. Going off what the experts have to say, it’s something we have to keep doing.

Why keeping close female friends gets harder as we get older

There’s a rather boring reason keeping close friendships gets harder as we get older: we stop seeing each other by accident. “Friendships need time, availability and repeated contact, and adulthood often removes all three,” says Psychologist Dr Sophie Mort. “Work, relationships, children, caring responsibilities and simply having less energy can mean that the spontaneous contact we had earlier in life becomes much harder to maintain.”

​Which explains my newfound ability (I thank my fully developed prefrontal cortex for this) not to be offended when a friend doesn’t reply for two business days. We have jobs, partners, children, admin, ageing parents, and occasionally, absolutely nothing left to give. However, be aware of the subtle trap here: giving each other grace can quietly morph into giving up.

“Friendships rarely disappear because somebody consciously decides, ‘I no longer value this person,’” says Moenie. “More often, tiny moments of friction accumulate.” Time. Distance. Competing Demands. We can start interpreting a missed message as evidence of how much someone cares, when sometimes life is simply getting in the way.

Not to mention there’s a bigger cultural problem at play: “We tend to overrate romantic relationships compared to platonic friendships,” Moenie says. “Friendship is often treated as a sideplot, by accident.”

The Irony: the busier our lives become, the easier friendship is to prioritise - and the more important that friendship may become. “There is a danger in continually placing our friendships on the back burner,” says Moenie, “because these are often precisely the periods when that support becomes most important.”

How to prioritise the friendships that actually matter

Trying to be a better friend takes up a huge, unrented space in my mind. So, I wouldn’t be doing my journalistic duty if I didn’t ask the question we all want answered: without turning friendship into yet another self-improvement project, what actually makes the biggest difference to maintaining friendships that matter - and, given what we now know, perhaps even living longer?

The answer, according to behavioural science, may be less about trying harder and more about making friendship harder to lose. “Changing the environment often works better than relying on motivation alone,” explains Moenie. Her advice is to make friendship “Easy, Attractive, Social and Timely - the EAST framework. Pair a catch-up with something you already enjoy. Make plans recurring rather than renegotiating them every time. Reach out when the cue naturally appears, rather than waiting for the mythical moment when everyone is free.”

There’s also what Moeni calls an “implementation intention”: deciding in advance when and where something will happen. “We should catch up” is a lovely sentiment. “I’ll call you on my commute home Thursday” is a plan.

And I like her suggestion to lower the threshold for what “counts” as connection. “One of my favourite areas of research looks at weak ties” - the work friend you see in the kitchen, the neighbour you chat to, the person at the pet shop who remembers your cat. These small interactions can boost happiness and feelings of belonging, too.

A case for showing up

I started this piece wondering whether I was spending enough time with my friends. I’m finishing it wondering why we ever decided friendship was something we could afford to put on hold. Because the women we make time for, inconvenience ourselves for and show up for aren’t a nice addition to our lives. They are part of what keeps us well, and quite possibly, on this planet for longer. So, consider this your sign to hug your friends that little bit tighter. You’ll find me doing the same.

Shop MC UK's Connection edit: