Do Dogs Get Adrenaline? Stress Hormones and Reactive Behaviour
Updated: 3 days ago
When a dog barks, lunges or snaps at something that worries them, it's easy to focus on the behaviour. Underneath, though, there's a lot going on in their body. Stress hormones like adrenaline and cortisol shape how a dog feels and reacts, and they don't switch off the moment the trigger has gone, which is why the next bit of the walk often goes wrong too. Here's how stress hormones affect reactive behaviour, whether dogs get adrenaline like we do and what that means for training.
THE SHORT ANSWER
Yes, dogs get adrenaline, just like people. When a dog feels threatened, startled or very excited, their body releases adrenaline and cortisol. Adrenaline gives an instant burst of energy, raising the heart rate and tensing the muscles ready to fight, run or freeze. Cortisol keeps the body in a stressed state for longer and can stay raised for hours, sometimes days, after a big scare. This is why reactive dogs can seem jumpy long after a walk and why one stressful event can make the next reaction come faster. To help, keep your dog below their threshold, give recovery time after a big reaction, protect sleep, and train in short, calm sessions when stress levels are low.
What are stress hormones?
Stress hormones are chemicals the body releases to cope with a threat. In dogs, the two main ones are adrenaline and cortisol.
They're not bad. They help a dog react quickly to danger. Problems start when they're released too often, too easily or for too long.
Do dogs get adrenaline?
Yes. Dogs have the same basic stress response as we do. When something worries or excites them, the adrenal glands release adrenaline within seconds.
Adrenaline raises the heart rate, speeds up breathing, sends blood to the muscles and sharpens the senses. It's the "fight, flight or freeze" response. You might see a dog go stiff, stare, bark, lunge or try to escape.
Cortisol and why it lingers
Cortisol works more slowly but lasts longer. It keeps the body ready for action and can stay raised for hours, and sometimes days, after a big stressful event.
That's why a dog who had a fright on the morning walk may still be jumpy in the evening. It's also why one reaction can make the next one more likely. Read understanding trigger stacking in dogs.
How stress hormones affect behaviour
When stress hormones are high, dogs find it harder to think, learn and settle. The signs can build over the day. You might notice:
quicker, bigger reactions to triggers
trouble focusing or taking food
restlessness, pacing or panting
poor sleep
more barking or startling at noises
a short fuse with other dogs or people
None of this is a dog choosing to be difficult. Their body is in a different state.
Why training doesn't work when stress is high
A dog flooded with adrenaline can't learn new skills. The thinking part of the brain takes a back seat while the survival part takes over.
That's why it's so important to train below your dog's threshold, at a distance where they can notice a trigger but still eat, play and respond to you. Read why walking reactive dogs is still essential.
How to help your dog's stress levels come down
Lowering stress gives training a chance to work. Read dog decompression for more. These are the steps that help most:
give two or three quiet days after a big reaction
choose quiet walking routes and times
use sniff walks and scent games to help your dog unwind
protect sleep, as most adult dogs need 12 to 14 hours a day
keep routines predictable
train in short sessions when your dog is calm
ask your vet if stress seems constant or extreme
Long-term stress
Dogs who live with stress every day can become sensitised, so they react to smaller things more quickly. Long-term stress can also affect digestion, sleep and the immune system. Read gut health and behaviour.
RENEE'S TIP
Keep a simple calendar and mark any day your dog has a big reaction. Then plan the next two days as calm days. Many owners find their dog reacts less often once they stop stacking stressful walks back to back.
QUICK CHECK
ā Dogs get adrenaline and cortisol, just like people
ā Adrenaline is fast, cortisol lingers for hours or days
ā High stress makes reactions faster and learning harder
ā Train below threshold, when your dog can still eat and respond
ā Give recovery days, sniffing and sleep after a big reaction
ONE-TO-ONE HELP
Help with a reactive dog
If your dog reacts on walks and struggles to calm down afterwards, I can help you build a plan in an online Dog Behaviour Consultation from wherever you are.
Online on Teams, wherever you are. 30 or 60 minutes.
FAQs
Do dogs get adrenaline?
Yes. Dogs release adrenaline when they're scared, startled or very excited, just like people do.
How long does adrenaline last in dogs?
The adrenaline rush passes fairly quickly, but cortisol can keep stress levels raised for hours or even days.
Why is my dog still jumpy hours after a scare?
Cortisol lingers after a stressful event, so your dog's body stays on alert for some time.
Can stress hormones cause reactivity?
They play a big part. High stress hormones make dogs react faster and find it harder to settle.
How do I lower my dog's stress levels?
Give recovery days, quiet sniff walks, plenty of sleep, predictable routines and train below threshold.
ABOUT THE AUTHOR
Renee Patience Ā· National Dog Trainer of the Year 2025
Founder and head trainer of Paws Academy, with more than 30 years training dogs and a Level 6 Diploma in Applied Canine Behaviour. Renee has competed in agility, obedience and heelwork to music across the UK, including at Crufts and Olympia, has appeared on CBBC, and is the author of the Modern Training Guides and the Modern Breed Handbook series. Pictured with her boxer, Kookie.
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