Blog — Reactive Dogs

  How movement and joy build ventral vagal engagement When most people think about a regulated nervous system, they imagine stillness. A quiet dog lying calmly at their feet. Slow breathing. Minimal movement. A kind of subdued composure that looks peaceful from the outside. But safety is not the same thing as stillness. According to Polyvagal Theory, developed by Stephen Porges, our autonomic nervous system moves through different states depending on whether we perceive safety or threat. The ventral branch of the vagus nerve supports connection, social engagement, curiosity, and flexibility. When this system is active, we feel safe enough...

The enteric nervous system (ENS) is a vast network of neurons embedded in the lining of the gastrointestinal tract. It contains hundreds of millions of neurons — comparable in number to the spinal cord. It’s called the “second brain” because: It can function independently of the central nervous system. It produces and responds to many of the same neurotransmitters (including serotonin and dopamine). It communicates bidirectionally with the brain through the vagus nerve. It directly influences inflammation, immune activity, and stress signaling.   In fact, about 90% of serotonin is produced in the gut, not the brain. So when we...

    Dogs don’t act out of spite or mischief—what looks like “bad behavior” is often a window into their nervous system at work. To truly understand why dogs react the way they do, we need to step back and see their brains not as moral arbiters, but as evolutionary survival machines, finely tuned to sense threat, reward, and opportunity. The Limbic Orchestra: Emotions in Motion At the core of your dog’s emotional life is the limbic system—a network of brain regions that regulates fear, motivation, pleasure, and memory. Amygdala: The emotional alarm bell. Detects danger and triggers rapid defensive responses....

  Fitness and mobility don’t just change what a body can do—they change what the nervous system believes is possible. A nervous system is constantly asking one core question beneath awareness: “If something goes wrong, do I have options?” When an animal has strength, coordination, balance, and ease of movement, the answer is more often yes. That “yes” matters deeply. It creates a baseline sense of agency—the felt understanding that one could move away, brace, climb, stabilize, push off, or hold ground if needed. Even if no threat is present, the nervous system tracks this capacity quietly in the background....

  Many dogs who struggle with reactivity, behavioral changes, or sudden “attitude shifts” are quietly carrying something we don’t always see: pain that’s being filtered through the nervous system. To understand why pain can hide during activity, show up during rest, and dramatically increase reactivity, we need to talk about three related—but often confused—concepts: Nociception, Stress-Induced Analgesia, and Pain. Nociception is not pain Nociception is the nervous system’s process of detecting potential tissue damage or threat—things like excessive pressure, inflammation, chemical irritation, or joint strain—and sending that information to the brain. Importantly: Nociception is the signal Pain is the experience...