Stress is a state in which the dog’s body is alert and ready to flee from danger or fight enemies. Stress can be positive or negative – being alert in danger is critical for survival!

Hormones

Stress hormones are produced by the endocrine glands: hypothalamus, pituitary, and adrenal glands (HPA axis). Stress hormones include adrenaline and cortisol. The amygdala plays a key role in processing emotions like fear, the hippocampus is involved in memory and learning, and the prefrontal cortex is responsible for decision-making and moderating social behavior. These brain regions work with the HPA axis to regulate the stress response. Any form of stress can increase cortisol production.

Acute Stress

During short-term stress, the HPA axis is activated, releasing cortisol. Cortisol acts as a “stress manager,” helping the dog adapt by mobilizing energy, increasing alertness, and temporarily suppressing non-essential functions like digestion or growth. Once the stressor is removed, cortisol levels normalize. Short-term stress is therefore not harmful and can even promote learning and adaptability.

Chronic Stress

Long-term stress, however, is harmful. Hormonal balance is disrupted, leading to continuously high cortisol levels. Persistently elevated cortisol negatively affects both physical and mental health, triggering a biochemical chain reaction involving the brain, adrenal glands, pancreas, and liver.

Effects of High Cortisol

Excess cortisol can have multiple negative effects: permanently increased heart rate, respiration, and body temperature, muscle discomfort from lactic acid, enhanced inflammation, elevated blood sugar, muscle waste products, and digestive issues. Stress also weakens the immune system, making your dog more susceptible to illness.

Chronic cortisol exposure can cause changes in the brain, such as reduced neurons in the hippocampus and altered amygdala function, leading to increased anxiety. Long-term stress can also contribute to obesity, heart disease, and digestive problems.

Mental Health and Behavior

Chronic stress can lead to persistent anxiety, nervousness, or hyperactivity, negatively affecting a dog’s overall well-being and quality of life. Behavioral changes may include increased aggression, excessive barking, or destructive behavior. Research shows that dogs under prolonged stress have a reduced ability to learn and retain new information.