Cortisol in Dogs: The Stress Hormone, Exercise, and Chronic Stress

What is cortisol in dogs?

Cortisol is a steroid hormone produced by the adrenal cortex that belongs to the group of glucocorticoids. It is released during stress—whether physical or psychological—as part of the HPA axis (hypothalamic-pituitary-adrenal axis). In acute situations, cortisol is essential for survival: it mobilizes energy, sharpens alertness, and prepares the body for fight or flight.

Chronically elevated cortisol levels are the problem: they suppress the immune system, impair memory formation, disrupt sleep, and reduce the dog’s ability to learn. A dog under constant stress learns less effectively—not because it “doesn’t want to,” but because cortisol directly inhibits hippocampal function and plasticity.

Background + Scientific Context

Hennessy et al. (2001, *Physiology & Behavior*, PubMed 11476825) measured plasma cortisol levels in dogs at an animal shelter: Upon arrival, the dogs exhibited significantly elevated cortisol levels—which returned to normal in most animals only after several days. Solitary confinement in kennels and noise were the strongest stressors. This shows that the environment has a direct, measurable influence on the stress hormone profile.

Coppola et al. (2006, *Physiology & Behavior*, PubMed 16979278) investigated whether human contact lowers cortisol levels in shelter dogs: Interaction with a familiar person measurably reduced cortisol levels—touch and communication thus have demonstrable hormonal effects. For training, this means: Positive, relaxed interaction before training lowers cortisol levels and improves willingness to learn.

Dreschel (2010, Applied Animal Behaviour Science, PubMed 20375965) demonstrated that anxiety and chronic stress in domestic dogs were associated with a shorter life expectancy and poorer health: dogs with a fear of thunderstorms or generalized anxiety were more likely to suffer from skin and gastrointestinal disorders. Cortisol serves as a link between anxiety and physical health.

Vitomalia-Position

Training under constant stress is ineffective—regardless of the method used. A dog with chronically elevated cortisol levels (due to fear, aversive methods, social stress, or behavioral issues) learns more slowly, makes more mistakes, and is more likely to develop aversion to learning tasks. Aversive training methods have been shown to increase cortisol levels; positive methods used in a relaxed setting lower them.

We recommend taking cortisol seriously as an invisible factor that affects training. If a dog “isn’t learning,” the first question to ask is: What is its stress level?

When does cortisol become a concern in dogs?

• If training has plateaued: Dog is resistant to learning despite motivation → Check cortisol levels (context, stressors)
• Signs of stress: yawning, lifting a paw, licking — often caused by cortisol
• As an argument against aversive methods (→ Aversive stimulus): elevated cortisol levels caused by pain or threats hinder learning
• In Cushing's syndrome: Hypercortisolism as a disease
• After intense or negative experiences: Cortisol levels take time to return to normal (24–72 hours)

Practical application

Acute vs. chronic cortisol:

Location	Cortisol effect	Relevance to training
Short-term, manageable stress	Rises briefly, then quickly returns to normal	Workout went well
Bad experience (aggression, punishment)	Significantly elevated, elevated for 24–72 hours	Do not exercise immediately afterward
Chronic stress (posture, anxiety, social)	Chronically elevated	Training routine disrupted
A positive, relaxed workout	Normal to slightly lowering	Optimal learning conditions

Support cortisol breakdown: - Schedule a study break after stressful situations - A calm, predictable daily routine - Social interaction with people you know - Enough sleep and a place to retreat - No consecutive stressful events without time to recover

Common Mistakes & Myths

• "Stress makes dogs stronger and more alert during training." It provides a short-term boost but is counterproductive in the long run. Chronic stress inhibits memory formation in the hippocampus—learning is slowed down, not accelerated.
• “Cortisol is only relevant in cases of illness.” Behavioral cortisol is not a sign of illness. It is the normal stress response—but if it remains activated over the long term, it has direct consequences for training and health.
• “A dog that appears calm is not stressed.” Hidden stress (freezing, suppression of stress signals) can cause cortisol levels to rise just as high as visible agitation.

Current State of Research (2026)

Cortisol monitoring using non-invasive methods (saliva, hair, urine) is becoming standard practice in canine research. For the first time, hair cortisol measurements provide insights into chronic stress levels over a period of weeks. Research on cortisol patterns in various training paradigms (positive vs. aversive) consistently confirms that aversive methods increase cortisol levels.

Frequently Asked Questions

How can I tell if my dog is under constant stress?

Signs of stress such as frequent yawning, licking, pawing, diarrhea, weight loss, poor sleep, overreacting to everyday stimuli, or sudden changes for the worse in behavior may indicate chronically elevated cortisol levels. Consult a veterinary behaviorist if these signs persist.

How long does cortisol remain elevated after a stressful event?

After an acute, intense stressful event, cortisol levels in dogs usually return to normal within 24–72 hours—depending on the intensity of the event and the dog’s individual predisposition. During this period, the quality of training is limited; it is advisable to take a break from training.

Does positive training lower cortisol levels in dogs?

Yes—relaxed, predictable, positive-reinforcement training in a calm environment measurably lowers cortisol levels. The effect is particularly strong when the dog develops a sense of control and predictability over events (a sense of control reduces the stress response).

Related terms

• Signs of stress in dogs
• Aversive stimulus in dogs
• Reward History in Dogs
• Cushing's Syndrome in Dogs
• Anxiety in Dogs
• A learning break for dogs

Sources & Further Reading

1. Hennessy, M. B., Williams, M. T., Miller, D. D., Douglas, C. W., & Voith, V. L. (2001). Influence of male and female petters on plasma cortisol and behaviour: can human interaction reduce the stress of dogs in a public animal shelter? Physiology & Behavior, 61(3), 337–345. https://pubmed.ncbi.nlm.nih.gov/11476825/

2. Coppola, C. L., Grandin, T., & Enns, R. M. (2006). Human interaction and cortisol: can human contact reduce stress for shelter dogs? Physiology & Behavior, 87(3), 537–541. https://pubmed.ncbi.nlm.nih.gov/16979278/

3. Dreschel, N. A. (2010). The effects of fear and anxiety on health and lifespan in pet dogs. Applied Animal Behaviour Science, 125(3–4), 157–162. https://pubmed.ncbi.nlm.nih.gov/20375965/