Stress & Cortisol; Why Your Dog Can’t Learn & Think Clearly

Daina Beckman

Dog Behavior Specialist

Happy Tails Dog Behavior & Training



When a dog is exposed to a stressor or anxiety, a cascade of what is referred to as the stress response happens. It includes the behavior/endocrinal response fight/flight/freeze. Examples are: dog/dog attacks (dog fights), shying away from women with long dark hair (flight), dogs standing still and trembling in the bath (freeze). The stress response is controlled by two hormonal systems and both include the adrenal gland. At the initial stressor the hormones are activated by the Sympathetic Nervous System and are released by the brain. These hormones trigger the release of adrenaline form the adrenal gland. About 20 minutes after the onset of this “cascade” the adrenal gland secretes glucocorticoids the most commonly known of these is Cortisol.
The increased Cortisol affects the breathing rate which increases, the heart rate and blood pressure go up, digestion stops, and vigilance goes up. As a result the thought process changes. Muscles are fueled so that the dog can fight or flee to ensure its survival in the situation. Glucocorticoids secreted by the brain near the end of the cascade repair and prepare for the next emergency. This state of living contributes to behavior problems. High levels of adrenaline are associated with heightened vigilance, anxiety, lowered thresholds of sensory perception; these make the dog more reactive to stimulation, rather than thinking. Higher levels of glucocorticoids cause an overactive stress response and depression. After a stress response it can take days for the glucocorticoids to go back down to baseline levels. If the dog has another stressful situation before this happens the entire cascade of the stress response starts all over. The dog will become sick physically and will become physiologically maladaptive if this goes on long enough. The dog will often over react to situations, or react inappropriately, or may even become listless. This is what happens when the sympathetic nervous system which governs the stress response is triggered.

The parasympathetic nervous system governs eating and recuperative functions. They are parallel branches of the autonomic nervous system which governs all the involuntary actions of the muscles, glands, and blood vessels. Each of the two systems need yet oppose each other. They can not operate at the same time without causing the dog problems which usually show up in the gut. So here is how it works out. If you punish the dog or expose him to what HE FEELS is stressful, you now trigger a stress response of fight/flight/freeze, by doing this the dog can no longer think, but only react to stimulation. Your dog now has a heightened vigilance/aggressive or depressive behavior response.

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