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Managing Arousal in Dogs - Trigger Stacking 101

Updated: Jun 23, 2023

Managing arousal in dogs, trigger stacking 101

Ever wondered why your dog can walk past 10 dogs on a walk, but then on the 11th dog they start barking? Or why your dog can cope with walking through town one day, but struggle to respond to simple cues in the same location the next? Or perhaps your dog loves playing fetch or tug with you, but after the 5th game, they start jumping up and biting you?

Ultimately, it comes down to arousal.

The word ‘arousal’ comes with many connotations, and while it’s becoming a more widely recognised term when talking about dog behaviour, it’s often still met with some confusion. However, understanding what it means for your dog’s behaviour is often key when it comes to improving behaviour issues and keeping your dog calm and happy.

Dog standing by the water

Arousal essentially refers to a dog’s level of responsiveness. It could be their responsiveness to events instigated by you (e.g. cueing the dog to sit), or events they encounter within the environment (e.g. other dogs).

When exposed to an exciting or stressful stimulus, the brain floods with excitatory chemicals, including adrenaline and cortisol, which impact consciousness, attention and information processing.

Arousal is not exclusively linked to negative events, like something scary happening, it also occurs in positive events too, for example, playing with other dogs or a game of fetch. It must be considered in all aspects of a dog’s life, not just the negative ones.

It also isn’t always a bad thing, sports dogs need to learn to work and think in high states of arousal, it quickens their responses and allows them to operate at optimal performance levels. Similarly, many working dogs, including police dogs and search dogs, may often be working in high arousal states. The difference is that these dogs have learnt how to work efficiently at high arousal, if they hadn’t then they wouldn’t be able to perform their tasks at optimal levels.

Why is Arousal Important?

Dog sniffing another dog

Arousal impacts how positive and negative events are processed and the resulting emotional response. Depending on arousal levels, the same event could lead to different emotional and behavioural responses.

For example, in a low arousal state, a dog may feel calm about greeting another dog and enjoy a friendly interaction, whereas in a high arousal state, they may feel tense and frustrated and the interaction could turn negative quickly.

Too much arousal can reduce the ability of the thinking part of the brain and increase the survival response (flight or fight). Increased arousal is a normal response to perceived threats or stressful moments (good and bad stress), but it can become excessive and detrimental to normal life.

Dog bucket of arousal

After a stressful event, the initial release of adrenaline should clear soon after the trigger has gone but the glucocorticoids that were released in the response can take between 48hours to 6 days to clear, depending on the individual and how intense the reaction was.

Each stressful event causes a rise in adrenaline and cortisol, as these hormones build up the dog will have less tolerance for daily events because their systems are repeatedly flooded with hormones.

In turn, all their energy is focused on maintaining some balance in the presence of these chemicals and there is little left to deal with outside challenges.

Remember this stress can come from positive, exciting events as well as the negative ones.

Every event which increases arousal pushes the dog closer to their ‘threshold level’ and this is where problems begin to show.

Trigger stacking

If the dog doesn’t have opportunities for their arousal levels to reduce, they will be spending more and more time close to, or over, their threshold level.

Some dogs have a fairly high threshold and it takes a lot to push them over, while others will have very low tolerance and are quickly tipped over their threshold level.

This is also known as ‘trigger stacking’ and it can explain why some days your dog may appear to cope better with stressful situations and other days they just can’t.

Think about when you play a game of tug or fetch with your dog, at some point during the game does he start to become ‘crazy’? Grabbing your hands, jumping at you, barking for you to throw the ball? Or maybe you’re playing fetch in the park and another dog comes over, your dog suddenly rushes over, barrels into the dog or starts growling at it? These types of behaviour can come as a surprise to us or they might be the reason we give up playing with our dogs, because they turn unpleasant during games… this is where arousal comes into play!

Things like playing fetch, playing with other dogs or meeting new people can all lead to higher levels of arousal in our dogs. When dealing with arousal and working to reduce or manage it, it’s important to include all areas of your dog’s life. Every time arousal is increased, regardless of the cause, the dog is pushed closer to their threshold level, making them less able to think and respond, and more likely to react or disengage.

Instead of assuming your dog is being naughty, stubborn or even aggressive, consider whether he’s actually in a highly aroused state and therefore unable to process your commands or requests… his brain is simply somewhere else and he has bigger concerns to focus on.

Coping with Arousal

Arousal isn’t always a bad thing, we don’t always want our dogs to live in a neutral state, never getting excited, stressed or frustrated, because after all these emotions are part of daily life and keep us functioning!

For dogs who are good at managing their arousal levels, it’s probably something you will never have to think about, your dog may get excited and then calm down quickly, they may spook briefly at something but recover fast, or they may switch on to training and focus reliably but also switch off at the end.

Dog sniffing

Your dog may try to lower their own arousal levels with displacement behaviours such as zoomies, having a check out, sniffing, licking, scratching, yawning, digging, spinning, chewing, biting, growling etc. Pay attention to your dog's body language so that you can spot trigger stacking early.

These dogs are wonderful and naturally have great skills. For others, it takes a lot of work to teach them how to manage their arousal levels and how to cope more appropriately in times of high arousal.

There may be a level of acceptance required if you have a dog who struggles with arousal, it’s possible to teach them new skills to cope better, but they may also need long-term management to avoid arousal levels escalating. This may include, rest days with no walks and no stressful triggers, regular rest time in a quiet room or safe space, fewer high arousal activities like playing fetch, and avoiding situations which trigger high arousal.

When we’re thinking about arousal, we must primarily consider WHY arousal levels are increasing; this is the starting point of teaching your dog how to cope better and manage their arousal levels better. You can teach all the calm or incompatible behaviours you want but if you don’t tackle the underlying emotions and causes, your dog is unlikely to learn to cope better with arousal.

A few typical reasons why arousal levels increase and why dogs become trigger stacked:

  • Too many stressful or exciting events

  • Too little rest

  • Overwhelming environments

  • Fear

  • Frustration

  • Excitement

  • Pain

  • Digestive upset

  • Allergies

This is where you can apply a combination of management and training to help improve your dog’s behaviour and teach better arousal skills. The starting point is always management to allow your dog to de-stress and return to baseline levels…

  • Take a break – avoid stressful situations and triggers where possible so your dog can fully relax. In extreme cases this could take several weeks, for others they may just need a day or two to decompress. This may include no walks, no exciting games/activities, a quiet room away from stressful noises or events

  • Change the environment – if your dog finds certain events stressful (good or bad), try to keep a balance so they have regular ‘rest days’ from these triggers. For example, quiet walk days, no high-arousal play days, chilled days at home. While working on arousal issues, start in quieter environments and avoid any where your dog is over-aroused and unable to learn

  • Build confidence and control – whether your dog struggles with fear or frustration, working through confidence building or impulse control is important in order to tackle the underlying emotions. Alongside this, management is vital otherwise any progress will continually be lost when your dog is pushed over threshold

  • Teach your dog how to lower their own arousal levels - encourage sniffing, let your dog have 'check out' breaks from training sessions, give your dog something to chew/lick etc. Starting scentwork with your dog is a tried and tested way to reduce arousal levels

  • Look at your dog's diet and health: Our dog's arousal levels can rise when our dogs have digestive upsets, allergies and pain. It's important to get your dog fully checked by the vet and get on top of any digestive upsets, itchy skin or any suspected pain issues

Dog barking

In all of this, you must always consider your dog’s emotional state and aim to work within their coping level. If you keep pushing them into situations which increase their arousal levels and push them close to or over threshold, they will never be able to learn effectively because their body will be in a constant state of stress.

Not only can this lead to increasingly challenging behaviours, it will also limit their ability to progress with any training.

You need to always begin training in environments where your dog is able to learn, and in order to do this, they need to be in a lower state of arousal. Alongside this, your dog needs time to recover and relax, especially if they’ve experienced a stressful event. If your dog struggles to regulate their rest time themselves, it’s important to help them out and teach them to rest properly throughout the day, this may mean using a crate or quiet room where they can sleep undisturbed.

Arousal is a complex area to think about, it can impact dogs in many ways and individuals will vary in their ability to tolerate and manage arousal. Understanding how arousal plays a role in your dog’s behaviour, and the underlying emotions and causes, will be key in improving any challenging behaviours your dog displays.

Seeking help from an experienced professional is highly recommended, they will be able to help spot the signs of arousal in your dog and support you with finding ways to manage their triggers and teach better skills.

Written by Naomi White

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