I was three kilometres into a run last week when I pulled my earphones out and stopped.
Nothing was wrong with the music. It was a good playlist — one I'd put together myself. High energy, right tempo, tracks I like. But something felt off. The songs weren't matching what my body was doing. My heart rate was climbing, my breathing was getting ragged, and the music was pushing me harder when what I actually needed was something to bring me back down.
I stood on the side of the road in Ibiza, hands on my knees, and thought: I've spent twenty years studying exactly this problem. Why does the running experience still feel this broken?
Let's start with what everyone already knows.
Music makes you run better. This isn't controversial. Put on a fast song and you speed up. Put on something you love and the kilometres feel shorter. Every runner knows this instinctively, and science backs it up — research shows that synchronising your movement to music can reduce oxygen consumption by up to seven percent. Your body becomes more efficient when it locks into a rhythm.
The standard advice is simple: match the BPM of your music to your cadence. Jogging? 120 to 125 BPM. Pushing hard? 140 to 145. All-out effort? 150 to 180. Spotify has playlists for this. Every running blog has a guide. It's useful, and it works — to a point.
But that's not the whole story. And it's not even the interesting part.
Here's what most people don't know about music and the body.
When sound enters your ear, it doesn't just get processed as "oh, that's a nice song." The vibrations travel through your eardrum, through the middle ear, and into the cochlea, where they're converted into electrical signals. Those signals hit the auditory cortex — but they don't stop there. They activate the limbic system, the emotional brain, which is deeply connected to structures like the amygdala and hippocampus. This is why music can make you cry, or feel invincible, or suddenly remember something from twenty years ago.
But there's a more direct pathway that almost nobody talks about in the running world.
The vagus nerve.
It's the longest cranial nerve in the body, running from the brain all the way down to the lower organs. It controls the parasympathetic nervous system — the "rest and digest" side, the one that calms you down after your fight-or-flight response fires. It regulates your heart rate, your breathing, your digestion. And here's the thing: it sits in extremely close proximity to the ear.
When you listen to music, the vibrations resonate through the vagus nerve. The right kind of music — at the right tempo, with the right sonic qualities — can actually stimulate a parasympathetic response. It can physically calm your nervous system. Slow your heart rate. Regulate your breathing. Not because you decided to relax, but because the sound triggered a physiological cascade that your conscious mind had nothing to do with.
I spent years researching this for people with dementia. We built AI technology that could analyse music the way the brain naturally does and select the precise music a person needed — not just music they liked, but music that would activate specific neurological pathways. Relax playlists that stimulated the vagus nerve and calmed the parasympathetic nervous system. Energise playlists that did the opposite. Reminiscence playlists that targeted the hippocampus for memory recall.
It worked. Not as a theory. As a product, used by real caregivers, backed by real research.
The same should be true for running.
When you run, your body is in a constant negotiation between two systems. The sympathetic nervous system — fight or flight — is driving you forward. Heart rate up, adrenaline flowing, muscles firing. The parasympathetic system — through the vagus nerve — is trying to modulate that response, keep things in check, prevent you from redlining.
And then there's the mental battle. The voice in your head that tells you to stop. The moment where your legs are fine but your brain has already quit. Music plays a role there too — but only if it's the right music at the right time. Not just something fast. Something that meets your body and your mind where they actually are.
At around 140 beats per minute, the two systems are roughly in balance. Above that, the sympathetic system dominates and your brain gets flooded with fatigue signals. This is why research consistently shows that music's performance benefits are strongest during low to moderate intensity running. Above about seventy-five percent of your aerobic capacity, the fatigue signals get so loud that your brain can barely process the music anymore.
So what happens on a long run? Your heart rate drifts upward. Your breathing becomes less controlled. Your parasympathetic system starts losing the battle. And your static playlist — the one that was perfect at kilometre two — is now actively working against you at kilometre fifteen. It's still pumping 140 BPM into your ears when your body is screaming for something that will help regulate, not escalate.
This is the gap. And it's enormous.
The current landscape gets pieces of it right. But playlists are static. They don't know your heart rate. They don't know you're struggling up that hill at kilometre twelve. They don't adapt. They don't support.
Nobody is combining real music — songs you actually love — with real-time biometric data and the musicology to understand why certain music works for certain bodies at certain moments.
The technology to do this exists. The science is there. The wearable data is there — your watch already knows your heart rate, your cadence, your pace, your variability. What's missing is the intelligence layer that connects it all. The thing that understands that you don't just need a song at 160 BPM right now — you need a song with specific harmonic properties that will activate your vagus nerve and bring your parasympathetic system back online before you blow up at the halfway mark.
That's not a playlist. That's a completely different product.
I've been working at the intersection of music, AI, and the human body for twenty years. I built the technology to analyse music at a neurological level. I've studied the vagus nerve, the limbic system, the connection between sound and the autonomic nervous system. I've published whitepapers, given talks, built products that used this science to help people with dementia.
And now I'm a runner. Training for half marathons in the Ibiza heat, feeling firsthand what every runner feels — that moment where the music stops helping and starts getting in the way.
I've got an itch I need to scratch.
I'm not ready to announce anything yet. But I'll say this: the relationship between music and the body is so much deeper than a BPM playlist. And the fact that nobody has built the thing that truly connects them tells me the opportunity is wide open.
Twenty years of pattern recognition led me here. Let's see where it goes.