What is Reactivity and What can you do about it
Reactivity in dogs can take many forms, but at its core, it is an emotional response that has escalated beyond the dog’s ability to cope. Whether driven by fear, excitement, or frustration, the result is the same: your dog becomes overwhelmed. This emotional overload puts both mental and physical strain on the dog, as their body is flooded with the stress hormone cortisol.
High cortisol levels don’t dissipate quickly, and this can lead to a phenomenon known as trigger stacking. This means that with each new trigger or stressful event, your dog’s ability to cope diminishes further. Reactions become more frequent, more intense, and more difficult to manage—creating a vicious cycle where triggers are increasingly overwhelming and responses are increasingly severe.
Let’s say your dog encounters a loud noise in the morning, a squirrel on the walk, and then sees another dog later in the day. Each of these moments are getting stacked on each other, like a game of Tetris. Eventually, even a small, seemingly insignificant trigger—like a person walking by—can cause an outburst. This is trigger stacking in action: multiple stressors build on each other, making your dog’s reactions quicker, stronger, and harder to recover from.
Every reactive dog has a unique set of triggers—things in their environment that spark an emotional response. Common triggers include other dogs, people, fast-moving objects like bikes or skateboards, or even unfamiliar sounds. Some dogs may react to one or two specific things, while others may have a much longer list. What’s important to understand is that triggers don’t have to be inherently threatening—they just have to feel that way to your dog.
Over time, if a dog is repeatedly exposed to these triggers without support or a way to cope, they begin to associate them with stress. That’s when you might see barking, lunging, growling, or freezing—not because your dog is “bad” or “aggressive,” but because they are trying to communicate: “I can’t handle this right now.”
The same goes for dogs who feel a strong need to greet everyone they see. Whether it’s constant exposure or missed chances to say hello, the build-up of frustration can lead to outbursts that look like they’re “screaming”: “Let me go!”
One of the most compassionate things we can do as dog owners is to remember this: your dog is not choosing to react this way. Reactivity is a stress response, not a conscious behaviour. Punishing or scolding a reactive dog only adds more stress and confusion, and often worsens the behaviour. Instead, our goal should be to build trust, reduce exposure to overwhelming triggers, and teach alternative behaviours.
Helping a reactive dog is a journey, but it’s one filled with growth for both dog and human. Here is a list of first to do steps
Identify triggers
Manage the environment - not the dog
Work under threshold - create a distance
Use positive reinforcement - reward for “good choices”
Get Professional Support
Working with a force-free, positive reinforcement-based trainer or behaviourist is highly recommended. Reactivity can be complex, and having a professional guide you can make the process more effective and less stressful for both you and your dog.
Living with a reactive dog can be challenging, emotional, and often isolating—but it’s also an opportunity to deepen your bond and learn to communicate on a much richer level. With patience, compassion, and the right strategies, progress is absolutely possible. Your dog isn’t broken, they’re asking for your help and guidance.
The journey might not always be easy, but it’s rewarding and healing. And remember: every step forward, no matter how small, is still a step forward.
