IS GIRLHOOD A HEALTH HACK? THE ANCIENT WISDOM OF FEMALE FRIENDSHIPS
By Lillian Snellenburg
I had a menty B this week, as my teenage clients would call it. I crashed out. I called my beautiful husband at work and sobbed down the phone. “Come swing a hammer for a while, darl?” he offered gently. “Take the dog for a walk? Sit in the garden?” I thanked him, told him I loved him, hung up, and contacted my best friend. Within 30 minutes, I was laughing. She didn’t try to solve my unsolvable problems. She didn’t offer solutions or distractions. She simply said, “Of course you feel that way. Of course.” We breathed. We cackled. Like girls. My nervous system settled. Because girls don’t always try to fix (though they absolutely can) what girls do best is hold.
They hold space.
They hold tissues.
They hold your hand.
They hold your heart.
Girlhood is as ancient as the brain. It is an evolutionary strategy. As women, we have survived because of the girls. Girlhood fosters wellness; whether it’s with winged eyeliner over charcuterie, all piled into a bed wearing pjs, or on the phone in the car trying to see the traffic through tears on the way to a meeting. The girls validate you. Regulate you. Monitor you. Keep you safe. Girlhood is travelling in packs to the bathroom. It’s telling a stranger at the gym that the guy in the stringlet keeps following her. It’s bringing lasagna over when you’ve had the baby and doing your washing without asking. It’s asking how that project is going. It’s listening to her talk about that thing again with the same care and enthusiasm she had the first time. It’s telling you, in the most eloquent and beautiful way, to pull your head in.
But why?
Why is girlhood so good?
The Evolutionary Wisdom of Girlhood
Girlhood isn’t just a phase. It’s a survival mechanism. It’s ancient. From an evolutionary standpoint women have always relied on each other to raise children, gather food, and stay safe from danger. Unlike the "fight or flight" response often associated with stress, women developed a parallel strategy: “tend and befriend”. This theory, championed by psychologist Shelley Taylor, explains why women form tight knit alliances, because these relationships literally keep us alive and have for about 700 million years.
Why the Girls?
It’s worth saying: men don’t quite have this.
Evolution shaped male and female nervous systems differently. While men are more likely to activate the fight or flight response under stress, women evolved to reach for each other. In the face of threat, we seek connection. We gather the girls. We assess the vibe. We co-regulate. In traditional hunter-gatherer societies, female alliances were a matter of survival. Women raised children communally, gathered food in synchronised rhythm, and relied on one another for safety. Men may have faced external threats like wild animals and rival tribes, women navigated internal ones like childbirth, caregiving and emotional risk. And they did it together.
Even today, studies show that female friendships activate the parasympathetic nervous system more reliably than male friendships do. When women connect, their bodies respond with lowered cortisol, increased oxytocin, and ventral vagal tone. When men bond, it’s often shoulder-to-shoulder, shared action, fewer words and that’s not wrong, it’s just different. Men are taught to regulate independently. Women have always regulated together. So when we cry to a friend, laugh in rhythm or whisper on the bathroom floor, we’re not being dramatic, we’re being ancient. We are doing what we have been doing to survive for thousands of years. We’re doing exactly what our nervous systems were designed to do.
Rhythms That Keep Us Alive
And then there’s this: the myth, the mystery, the dorm-room legend of menstrual synchrony.
You’ve probably heard it or lived it: spend enough time with your best friend, your sister, your housemates, and your periods start to align. Science has been debating this since the ’70s. Some researchers call it a statistical illusion and others argue it may be driven by scent, pheromones or environmental factors. But whether or not our cycles literally sync up, it’s the idea itself which points to something deep and wise in the way women’s bodies respond to each other.
From an evolutionary lens synchronised fertility could have offered a survival advantage. If women ovulated and gave birth around the same time then they could co-parent, breastfeed communally and support each other in postpartum recovery. This is the foundation of what anthropologists call alloparenting which is a system where caregiving is shared across a group. It still happens in many cultures today. For many eastern cultures it is life saving, and is even being adopted in the west. There’s also a theory that synchronised cycles may have reduced reproductive monopolies. In non-human primates dominant females often try to control access to mates. But if multiple females become fertile at once then that power dynamic breaks down and reproductive equity goes up. Everyone gets a chance to mother and the group becomes more resilient.
And beyond the logistics of mating and mothering, shared hormonal rhythms may have been essential for bonding. Fluctuations in estrogen and oxytocin throughout the menstrual cycle shape empathy, mood and receptivity. When women’s bodies move in similar hormonal arcs they may be more attuned to each other and more likely to laugh at the same joke, cry at the same scene or notice the same shift in energy across a room. Even without perfect synchrony, this shared emotional rhythm deepens connection. It's less about identical dates on a calendar, and more about a primal biological whisper: “I feel you. I’m with you. Let’s keep each other safe. Can I have a tampon?”
And when we live together, cry together, walk together then our bodies still remember this. Our nervous systems soften in sync. Our cortisol lowers. Our breath matches. We become, quite literally, safer in each other’s presence.
The Science of Safety: Polyvagal Theory and the Female Nervous System
Neuroscientist Stephen Porges calls it polyvagal theory. It’s a term for something you already know in your bones. Your nervous system needs other people to feel safe. Polyvagal theory explains how our bodies constantly scan for cues of safety or danger in a process called neuroception. It operates below the level of thought, shaping how we feel and respond before we even realise it. At the centre of this system is the vagus nerve, the body’s largest cranial nerve, winding from the brainstem through the heart, lungs, and gut. “Vagus” in Latin, means Wanderer. It’s a communication superhighway between brain and body and it governs what’s called the social engagement system.
When we feel safe, when we hear a warm voice, see kind eyes or move in sync with another, then the vagus nerve activates the ventral vagal pathway. This part of our nervous system slows our heart rate, softens our breath, supports digestion, boosts immunity, and fosters emotional attunement. Essentially, it’s the setting where we feel calm, curious, connected and alive. This is why a hug helps more than a breathing app. Why a friend’s voice note calms you in ways a mindfulness podcast can’t. Why girlhood in all its chaotic, synchronised and emotional mess is one of the most powerful regulators we have. Those long afternoons of shared silence and side-by-side scrolling is nervous system alignment. Walking home from school three across? Regulation. Crying, laughing, sleeping over, braiding hair? Ancient safety cues.
Girlhood is not just sweet. It’s somatic.
When Girlhood is Disrupted
But what happens when girlhood goes missing? When it’s cut short, sexualised or softened into something palatable for others? When trauma hits too young, when trust is broken and when closeness is replaced by comparison?
When connection is fractured, the body gets the message of We are not safe. And chronic stress becomes the baseline. The consequences are not just emotional, but physical. We have a dysregulated nervous system. Research shows disconnection and unresolved stress can contribute to autoimmune conditions, inflammation, IBS, anxiety and panic disorders, disordered eating, sleep disruption and chronic fatigue.
So it turns out, loneliness, or time without the girls, is as harmful to health as smoking 15 cigarettes a day. For many women, the loss of girlhood isn’t just symbolic. It’s somatic. Their nervous system doesn’t get to rest.
Reclaiming Girlhood as a Wellness Practice
So how do we get it back? The good news is: you don’t have to be 13 to benefit from girlhood. You can return to it, practice it, in fact; I prescribe it.
So call your friend. Sit beside someone who loves you. Let your nervous system borrow theirs. Hang out unproductively. Walk barefoot. Make bracelets. Dance to 2001’s greatest. Because your body doesn’t know the difference between then and now, but it remembers the feeling. Softness is sacred. Let someone hold you. Let the girls in. Let yourself cry. Let yourself be witnessed without needing to be impressive. Let someone say, “Of course you feel that way.” Match breath, voice, or movement with someone else. Whether it’s a yoga class, a walk, or a shared laugh, rhythm = regulation.
Be witnessed. And witness. The nervous system relaxes when it is seen. Practice being seen in your chaos. And seeing others in theirs without trying to fix or shrink it. Small, embodied acts of care matter more than words. Girlhood is showing up. Without being asked, with no toxic positivity, with food and love and time.
Girlhood is Medicine
Girlhood is crying in the car and sending a voice note that starts with, “I know we’ve talked about this a thousand times…” and still she listens. Girlhood is laying down on the bed with you in earth shattering silence and staring at the wall wondering what you’ll do with the life you have left. Girlhood is subscribing to a six minute podcast episode voice note recorded just for you about that same spiral they’ve had 12 times before. She still finds something new to say. Or not say. She just holds it with you. Because the nervous system doesn’t need novelty. It needs familiarity in the same voice and the same laugh. The same reminder: you are not alone.
Wellness doesn’t have to mean green juices, saunas, or supplements. Sometimes, it’s a voice on the other end of the phone whispering, “You’re not crazy. I’ve got you.”
Girlhood, in all its forms, is one of the most powerful nervous system regulators we have. It is ancient. It is intuitive. It is embodied safety. So this month, don’t just do self-care. Call the girls. Be the girl. Return to the practices that kept you alive long before you knew what a wellness routine was.
THE WOMAN BEHIND THE WORDS
Lillian Snellenburg is a registered psychologist, writer, and director of a private psychology practice on the mid-north coast of New South Wales. Her work is grounded in the treatment of anxiety, depression, trauma and major life transitions, with a special focus on the reclamation of feminine identity and power. After the stillbirth of her son, Sunny, she began writing from the raw edge of loss, drawing upon myth, nature, and the underworld as her compass. Connect with her @the.millennialpsych.
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ISSUE 07