Trigger Stacking

Do you ever have those days where the alarm goes off and everything just spirals? By the end of it, your patience is gone and you’ve snapped at someone you love.

It turns out, our dogs can have days like that too.

Let’s talk about trigger stacking. A trigger is anything that causes a stress response in your dog. This could be another dog, a pram, the postman, loud voices, or children running around. Triggers aren’t always visual—they can be sounds or smells too. And importantly, they’re not just things that make your dog anxious; they can also be anything that increases excitement or arousal.

When a trigger happens, your dog’s body releases stress hormones like cortisol and adrenaline—the chemicals responsible for the fight, flight, or freeze response. Some dogs cope well with this, but others may react by barking, lunging, jumping up, or trying to escape. A dog’s ability to handle stress can depend on factors like genetics and early socialisation.

The key thing to understand is that these hormones don’t disappear quickly. It can take hours—sometimes even days—for them to return to normal levels. This means your dog could still be feeling the effects of an earlier trigger long after the moment has passed.

Trigger stacking happens when multiple stressful or exciting events occur close together. Each one adds another “layer,” pushing your dog closer to their limit. Eventually, they may go over their threshold and react in a way you don’t like.

Imagine this:You head out for your first walk of the day. A man in a funny hat startles your dog. Fifteen minutes later, a cat appears and your dog lunges. Not long after, a child zooms past on a skateboard. You head home thinking nothing of it.

Later that evening, you go out again. Within minutes, another dog barks aggressively at yours. Your dog reacts. You move on, but just before you get home, a loud firework goes off—and now your dog just wants to escape and get back inside.

Each of these moments caused a surge in stress hormones. But there wasn’t enough time between them for your dog to fully recover. Like stacking building blocks, each trigger added pressure until your dog reached their breaking point.

If only one or two of those things had happened, your dog might have coped just fine. But on this particular day, it all added up.

Every dog has a threshold—the point where they can no longer cope with what they’re feeling, whether that’s stress, fear, excitement, or frustration. And just like us, every dog’s threshold is different.

Understanding trigger stacking helps us see why our dogs sometimes “overreact.” It’s not about being naughty—it’s about being overwhelmed. By recognising this, we can help keep our dogs below their threshold and set them up to succeed.

Imagine your has a bucket, the bucket is a way to think about the level of stress hormones they can deal with. Remember stress can be good and bad, so it can be positive events that add to the bucket and negative events that can add to the bucket.

Being aware of trigger stacking allows you to make kinder, more thoughtful choices for your dog. On days where more has happened than usual, it’s okay to swap the long walk for something calmer like a sniffy stroll, enrichment at home, or simply giving your dog time to rest and decompress. Remember, behaviour is communication—your dog isn’t trying to be difficult, they’re telling you they’re overwhelmed. By recognising the signs and adjusting accordingly, you’re not only preventing unwanted reactions, but also building trust and helping your dog feel safe in their world.