Behaviour vets and trainers often talk about arousal and the importance of minimising it in our anxious pets but what does that really mean?

The medical definition of arousal is a state of physiological alertness and readiness for action.

Simply put, this means that when an individual is exposed to a high level of sensory stimulation, their brain is flooded with excitatory chemicals such as adrenaline and cortisol.

In evolutionary terms this is important as it regulates consciousness, attention and information processing, all of which are vital in helping individuals stay safe.

However, too much arousal, or arousal of an anxious brain, can be bad. It has the effect of dulling down the logical, rational part of the cerebral cortex whilst at the same time ramping up the survival response (fight, flight, freeze and fiddle behaviours).

Hyper-arousal is a necessary and normal response to a life threatening situation but in everyday life it is unnecessary and abnormal – becoming detrimental to the animal both in terms of quality and longevity of life.

Aroused animals are reactive to their environment; reaching their threshold in response to a stimulus more easily. This means that they are more likely to continue to perform the very behavioural problems we are trying to change.

Neural pathways in the brain strengthen with repeated use; so the more times a behaviour is performed, the ‘better’ the animal gets at it. Strong neural pathways form an animals’ default response to a given situation and are much harder to change.

So the first issue in allowing an animal with behavioural problems and/or a mental health disorder to become aroused is that it promotes the very behavioural responses we are trying to change.

The second issue is the fact that hyper-aroused brains are poorly responsive to learning and memory. Much of our treatment requires behavioural modification via desensitization and counter conditioning (DS/CC). If the brain is not able to effectively process information from its environment via a DS/CC programme, then limited progress to replace the behavioural problem with an alternate emotional and behavioural response will be made.


So keeping a handle on arousal, especially in anxious or mentally ill animals, is obviously a good thing.

But how do we do this at a practical level?

We usually think of reducing arousal in terms of avoiding sensory stimulations that cause a negative emotional response within the dog.

This includes things that scare or frighten the animal – other dogs, loud noises or being left alone for example.

But arousal also occurs when the sensory stimulation produces a positive emotional response. This can include things like social play (with other dog friendly canines), playing a vigorous game of ‘fetch’ or a cat sitting on the neighbours fence (for a dog that likes to chase cats!).  

Therefore when we are treating anxious patients and talk to their owners about ‘reducing arousal’ as part of their treatment programme, we need to account for both negative and positive stimuli.

This can sometimes be a difficult concept for owners to grasp as they feel that their dogs should not be prevented from experiencing things they enjoy. It is especially difficult if the advice comes with other restrictions such as reducing walks or social interactions.

But every time the brains’ arousal levels rise, the animal gets closer to their threshold for reactivity.



And for many of our anxious patients, this means overt aggression



In contrast, experiences that promote calmness and relaxation will reduce arousal and reactivity levels in the brain. Things like ear/head massages (for dogs that like physical contact), food puzzles and nose work activities (which stimulate the ‘thinking’ cortex) and listening to calming music or audio books.

Making every attempt to reduce arousal levels, especially at the onset of a behavioural modification treatment programme, makes absolute sense and provides the animal with the best chance of being able to effectively learn new, better, behavioural responses.


Sometimes it can be confusing when our dogs’ response to a stimulus appears so different one day from the next. It is imperative that we remember to look at what events occurred in the preceding 24-48 hours as arousal levels are accumulative and increases in excitatory chemicals in the brain can take a couple of days to drop.


Take the same dog reacting in two very different ways to a visitor arriving at the home.

Scenario A:

Yesterday there was a thunderstorm. Today the weather was better so the owner took the dog to the local off leash park where it played with lots of other dogs. The neighbours’ kids had a birthday party in the backyard this afternoon with lots of loud music and laughter.

6pm the doorbell goes and a visitor arrives. The dog immediately goes crazy barking uncontrollably at their arrival; and is unable to be distracted by food treats.

Scenario B:

Yesterday the owner took the dog on a very long ‘sniff walk’ in the local state forest. This morning the dog was fed using a food puzzle toy. The owner has been sitting on the floor massaging the dog with long relaxing strokes whilst watching Andrea Bocelli in concert on TV for the past hour!

6pm the doorbell goes and a visitor arrives. The dog stares at the door but can remain focused on their owner as the owner cues (and then rewards) them for going to their bed to lie down.

Same dog. Same visitor. Different arousal level based on the dogs experiences the preceding day and therefore a very different behavioural response observed.


Understanding what makes our dogs aroused – both negatively and positively- and taking steps to minimise these factors is therefore imperative if we are to successfully reduce their reactivity and in turn their unwanted behaviour.

If in doubt as to what you should/should not be doing with your dog, please seek advice from a behaviour veterinarian or positive force-free trainer.  We are here to help!


By Dr Emma Hughes BSc (Hons), BVSc (Hons), MSc (Animal Behaviour & Welfare), MANZCVS (Veterinary Behaviour)

Dr Emma Hughes

Author Dr Emma Hughes

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