The Psoas–Nervous System Connection: Why Hip Tension Might Be Keeping You in Fight or Flight
Learn the science behind the nervous system and psoas connection and why keeping this tender muscle strong and supple is so important for nervous system regulation in our modern world.
I like to say my psoas and I are old friends, the kind that’s always trying to protect me, sometimes a little too much. It's like that loyal bestie who means well but doesn’t always know when to back off. My psoas tenses when I’m stressed, flares when I’m tired, and speaks up when I’ve been pushing too hard. It’s always on high alert, trying to keep me safe, even when the “danger” is just a long to-do list or a passive-aggressive email.
Over the years, I’ve learned to recognize that gripping sensation in my core and hips as a kind of message from my body: Hey, something’s off. And while I appreciate the heads-up, I also know that gently asking my psoas to soften is part of the ongoing dance of self-regulation. It’s not about forcing it to relax—it’s about letting it know we’re safe now.
What (and Where) Is the Psoas, Anyway?
If you’re wondering what on earth the psoas is, you’re not alone.
The psoas (pronounced SO-as) is a deep, powerful core muscle, there are two on each side: the psoas major and the often-overlooked psoas minor. These muscles originate along the lumbar spine, thread through the pelvis, and attach to the inner thigh bone (femur). As the only muscle that connects the spine to the legs, the psoas acts like a suspension bridge between your upper and lower body, keeping you upright, mobile, and (ideally) balanced.
It’s also deeply intertwined with your diaphragm, your primary breathing muscle, via fascial connections. This means your breath and your hips are quite literally linked, and this is one big reason some yogis and somatic practitioners call it the “muscle of the soul.”
To feel your psoas in action:
Try lifting one knee toward your chest while standing feel the deep muscle firing under your belly.
In constructive rest poses (lying on your back, knees bent, feet flat), tune into the deep belly space. Can you sense a subtle tension or gripping just below your navel? That may be your psoas holding on.
Try placing your hands gently on your low belly and breathing deeply into that space. Does anything soften or resist?
Meet Your Psoas: The Body’s Deep Core Connector
Imagine stepping off a curb and losing your balance, your core and hips tense instinctively. That’s your psoas jumping in to stabilize you. In a healthy state, it provides postural support and efficient movement. But when it’s too tight, it can pull your lower spine into an excessive arch (“swayback”), often resulting in low back pain. When it’s weak or overstretched, instability or hip and pelvic discomfort can arise.
This muscle isn’t just a hip flexor, it’s a key player in emotional and physiological regulation. Neuroscience backs up what many yoga teachers have long intuited: because the psoas connects the diaphragm to the legs, it’s a bridge between your breath, your movement, and your emotional center.
And here’s a fun anatomy fact: in animals, the psoas is the tenderloin (yep, the filet mignon!). No wonder it’s such a sensitive and responsive part of our bodies.
So if you’ve ever felt tight hips or a sore lower back after a long, stressful day, chances are your psoas is saying hello.
Psoas + Nervous System: Your Fight-or-Flight Muscle
Here’s where that over-protective bestie energy really shows up.
The psoas is often called the “fight-or-flight muscle”. Here’s how it earns that nickname...
When your nervous system detects danger, whether it’s a real threat (like a car swerving into your lane) or a perceived one (like an overwhelming inbox), your sympathetic nervous system kicks in, and the psoas tenses to prep you to run or defend yourself.
In mere seconds, your body floods with adrenaline, your breath gets shallow, and your psoas contracts without you even thinking about it. It's a primal reflex.
The problem is, today’s “tigers” are less about predators and more about traffic, deadlines, and scrolling the news. We’re not sprinting away from threats, but our bodies are still bracing for them.
And here's the kicker: that connection becomes a two-way street. A chronically tight psoas can send feedback to your brain that something’s still wrong, keeping you stuck in a subtle stress loop. The more the psoas stays contracted, the more it tells your nervous system: we're still in danger.
This cycle keeps stress hormones circulating, making you feel anxious or on edge even when nothing's wrong.
This alone is reason enough to get on your mat, don’t you think?
I’ll admit, I was once skeptical of the idea that a muscle could "hold" emotions. But science is catching up: one study found that people with higher levels of perceived stress had significantly tighter psoas muscles. Source
It’s not woo, just anatomy and nervous system science.
When Fight-or-Flight Becomes a Lifestyle
The trouble is, many of us are stuck in chronic low-level stress. It’s not one tiger it’s daily life. Juggling work, parenting, relationships, finances, and a never-ending news cycle.
Physically, this constant bracing tightens the psoas and related muscles like the quads, keeping us in a state of tension. Over time, this can lead to:
Lower back pain
Pelvic floor dysfunction
Hip stiffness
Digestive issues (a tight psoas can compress organs and restrict blood flow)
Emotionally, this might show up as:
Persistent anxiety
Irritability or restlessness
A general feeling of unease
I’ve felt it firsthand: that mix of tight hips and high alert. The body is wise, and the psoas is often the messenger.
Activating the Parasympathetic Nervous System
Here’s the good news: just as your body ramps up into fight-or-flight, it can also downshift into rest-and-digest. That’s the role of the parasympathetic nervous system—and one way to tap into it is by releasing the psoas.
Ever cried in pigeon pose? Had a wave of relief after a deep lunge? That’s your nervous system catching up to your body’s release.
Try my gentle Ground Up: Lower Body Yoga for Strength and Flexibility on YouTube, focused on calming the hips and nervous system.
Deep hip-openers in restorative yoga can signal to your brain: Hey, we’re safe now. But it’s not just about the pose, it’s about breath.
The Psoas-Diaphragm Link: Breathe Better, Feel Better
Your diaphragm and psoas are neighbors. They’re connected via fascia, meaning tension in one affects the other.
When your psoas is tight, it can restrict diaphragm movement, leading to shallow breathing. Likewise, if you’re breathing shallowly (hello, stress), your diaphragm isn’t moving fully, and the psoas doesn’t get the message to release.
A tight psoas = shallow breath.
A deep breath = a more relaxed psoas.
Try this:
Sit or lie down comfortably.
Place one hand on your belly, one on your chest.
Take a long inhale through your nose, aiming to fill the belly (not just the chest).
Exhale even more slowly, make it long and gentle.
Repeat for 2–3 minutes.
This kind of conscious, diaphragmatic breathing helps massage the psoas from the inside out and signals safety to the nervous system.
If you’ve ever taken an ice bath, you know breath is everything. It’s the only way to stay calm when your system wants to panic. (Breath helps there, too, but that’s a different kind of nervous system training!)
Yoga + the Psoas: Strengthen and Release
So how do you care for your psoas?
The answer: a balance of awareness, strength, and release. A well-rounded yoga practice does all three—stretching, toning, and relaxing this essential muscle.
Some go-to psoas-loving poses:
Warrior I
Low Lunge (Anjaneyasana or Dragon)
Triangle
Pigeon
Tree Pose
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The key is not collapsing into your hips, but staying buoyant and engaged. Think: tone and tenderness.
Here’s to a soft, resilient core, a calm nervous system, and a free and happy psoas.
Let’s flow, not fight.
"I like to say my psoas and I are old friends, the kind that’s always trying to protect me, sometimes a little too much. " Me, too! This is an amazing post!
I’m a massage therapist and I do a LOT of psoas work. It’s so powerful!!