Stress in Cats: Causes and Long-time Effects.

Stres u kota

What is commonly understood by "being stressed"? Generally, stress is associated with a negative emotional burden caused by a difficult situation, illness, worry, unpleasant experience, a sense of threat or the influence of various negative external factors. Our recognition of stress is based on a person’s behaviour, mostly showing anxiety and high agitation.

Stress is a physiological response of the body to changes in the world around us, both good and bad, independent of our will. The source of stress is therefore in ANY change, regardless of whether it is beneficial or not. The body doesn't know the difference between "good" and "bad" stress.

Scientists themselves find it difficult to define stress:

"Stress arises when individuals perceive that they cannot adequately cope with the demands being made on them or with threats to their well-being.” (R.S. Lazarus, 1966).

"Stress is the response of the body to any demand, whether it is caused by, or results in, pleasant or unpleasant conditions.” (Selye, 1976).

”Stress results from an imbalance between demands and resources.” (R.S. Lazarus and S. Folkman, 1984).

"The physiological or psychological response to internal or external stressors.” (APA Dictionary of Psychology).

In simple terms, we can distinguish four phases of response to a sudden stimulus:

I. A stimulus received by one of the five senses is picked up by the brain (e.g. an alien meow);

II. The brain classifies the stimulus as "threat" or "non-threat". If the stimulus is judged to be non-threatening then the reaction ends here. (e.g. a meow came from the TV, no strange cat is in sight). However, if it finds it disturbing, the brain immediately activates the nervous and endocrine systems to rapidly prepare the body for a fight-or-flight response;

III. The body remains alert and in “standby mode” until the threat is found gone;

IV. The body returns to a state of homeostasis, a state of physiological peace, when the threat is over.

The factor that triggers this chain of reactions can be any change, the arrival of a new cat, the change of apartment, disappearance of a cat / dog / another household member to which the cat was attached, bad relationships with another cat (they can be bad not only when we observe open conflicts – this would indicate that the relationships are already EXTREMELY bad), arguments between the owners, or things that are most difficult for owners to "track", such as the smell of another cat or dog coming from the staircase, a cat walking outside the window, some architectural elements (fluttering material, a scarecrow outside the window, etc.).These are only the most frequent ones, the list is much longer.

Stress can also be caused by the lack of proper space organisation, the aspect that is essential for the cat’s welfare even if there is only one in the household, and it is the source of stress of the worst kind - chronic stress!

The physiology of stress.

Two systems are involved in the response to a stressful stimulus: the nervous system and the endocrine system.

As far as the nervous system is concerned, we are most interested in the part that scientists call the autonomic system. The autonomic nervous system is a control system that acts largely unconsciously and regulates bodily functions, such as the heart rate, digestion, respiratory rate, etc., and consists of two fractions, sympathetic (responsible for stimulation), and parasympathetic (responsible for inhibition and relaxation).

The sight of a cat outside the window causes an immediate, unconscious reaction from the sympathetic system, which sends strong stimulating signals to the internal organs, equally strongly stimulating the endocrine glands (hormones), and equally strongly inhibiting the immune system, which is considered unimportant at the moment and somehow "turned off". Experts call this an immunosuppressive effect.


 Effect  Kind of response  Time
 Immediate effect  Adrenaline and noradrenaline released by by the nerve endings  2-3 seconds
 Immediate effect  Adrenaline and noradrenaline released by by the adrenal cortex  20-30 seconds
 Long-time effect  Cortisol and thyroxine  Minutes, hours, days, weeks


Well then, what will happen in the body of our cat looking at an intruder outside the window? We will not notice the majority of these reactions, our cat will simply “be calmly sitting"!

- Pupil dilation;

- Increased heart rate;

- Spasm of blood vessels;

- Elevated blood pressure;

- Increase in blood glucose levels;

- Increase in the level of lipids (fats) in the blood;

- Increase in muscle tone (especially in the neck and legs);

- Stimulating the work of the intestines;

- Bladder stimulation;

- Bronchodilation;

- Shallow and faster breathing;

- Release of substances that accelerate blood clotting.

All these changes will happen automatically each time the cat comes across something disturbing. If it is afraid of its neighbour's cat, the reaction will start every time the “enemy” appears, several or a dozen times a day. If another cat living in the same household or a family member is the cause of anxiety, then the stress reaction will happen so many times that it will be difficult to achieve periods of relaxation.

Adrenaline is the "first line" hormone and its levels drop quite quickly. Noradrenaline is a hormone that remains in the blood for a longer time, so its stimulating effect is present even after the "intruder" disappears from our cat's field of vision. The most dangerous hormone released in response to a change is cortisol. In natural amounts, it is a hormone extremely important in maintaining homeostasis and the balance of our body. Cortisol regulates the glucose and lipid metabolism, it also regulates the sodium-potassium balance (kidney function!). Unfortunately, its excess causes the "escape" of potassium, increases the level of glucose and lipids in the blood, and disastrously affects the immune system, blocking its proper functioning. Cortisol levels also rise dangerously when the body is deprived of sleep.

In normal circumstances, when the stress factor disappears or is recognized as an ordinary, harmless object, after the phase of arousal and readiness to "fight or flight", the parasympathetic, inhibiting system begins to work, i.e. the body tries to return to a state of homeostasis.

The nerve endings release acetylcholine, which, among other things:

causes dilatation of blood vessels,

lowers blood pressure,

slows down the heart rate,

reduces the strength of heart muscle contraction,

causes constriction of the pupils.

Everything is over, you can easily stretch and go back to your favourite activities, maybe take a nap?

Stress in itself is not bad, it is a normal adaptive mechanism. When a stressor disappears or is properly recognized and ceases to be a stressor (a constant, frequent guest, for example), our cat's body returns to balance, and the cat itself has a chance to learn how to behave in a given situation if it repeats (e.g. the cat stops hiding from the particular visitor, starts to linger in the room, watching from a safe spot).

The problem begins when the stress factor becomes a permanent element of the cat's life and exceeds our cat's adaptability. The body is constantly in a state of hormonal swing, constant agitation, which without a period of relaxation goes into a state of exhaustion, leading directly to disease, and in extreme cases even to death. The consequences of chronic stress are really dangerous in the long run.

- Fast heartbeat in too long periods, constricted vessels, pressure surges => serious heart diseases, including cardiomyopathies;

- The stimulation of the intestinal function often leads (it is sometimes one of the first symptoms of chronic stress) to intestinal "neurosis", generally its poor work and impaired nutrient absorption => seemingly causeless diarrhoea or constipation;

- The muscles of the walls of the bladder and urethra are also subject to similar stimulation due to stress hormones, excessive and too frequent contraction of these organs leads to narrowing of the urethra, urinary retention, and promotes inflammation of the lower urinary tract;

- Cortisol raises the level of cholesterol (fats) and blood glucose => diabetes, atherosclerosis == >> changes and diseases of the cardiovascular system, thrombotic diseases, hypertension and cardiomyopathies;

- Atrophy of lymph glands (thymus, spleen, lymph nodes), and consequently a drastic decrease in the number of white blood cells, which leads to the breakdown of immunity and diseases (again cortisol);

Chronic stress severely impairs thyroid function => heart disease and cardiomyopathies.

- Gaining weight is very rarely associated with stress, whereas it is often its direct derivative. Situations in which our cat eats little, but for unexplained reasons constantly gains weight, are very often the result of disturbed fat-glycogen balance and water retention in the body due to chronically high cortisol levels.

- Cortisol has another very serious negative effect: due to its constant excess concentration in the blood, the hippocampus cells, the part of the brain responsible for memory, learning and feeling emotions, die.

- In a situation of a very strong or chronic stress, we do not learn = >> inability to analyse the situation and apply an adequate solution.

It is not easy to recognize a cat living in chronic stress because we think that a cat should be nervous, aggressive, overstimulated. If that's the case, we usually notice the problem. It is much more difficult if our cat belongs to those who try to wait out an uncomfortable situation, pretend that nothing is happening, pretend to be sleeping. Trying not to notice what is bothering them, they start for example to groom excessively, sometimes licking their hair to the bare skin, they eat more often but hardly ever move or play, immediately settling down to an apparent sleep after each meal. They have unexplained recurring intestinal problems or cystitis, watery eyes, unmanageable allergies and intolerances. As they don't move or play, they get fat and are labelled “lazy”.

The owner very often notices the problem only after a routine check-up, when it turns out that the cat has diabetes, sick kidneys or circulatory problems. Even then, the only help the cat gets is medical treatment without looking for the cause in the psyche.

When do we suspect that our cat may be under stress?

Urinating or defecating outside the litter boxes. It is a behaviour that allows the cat to reduce negative emotions related to frustration, boredom, anxiety and living under chronic stress. Abdominal pain is very often the result of stress, and will effectively discourage your cat from entering the litter box. However, when dealing with improper elimination, we ALWAYS start with health examination, because regardless of the cause, we may already be dealing with inflammation, and this requires drug treatment.

What are the symptoms of stress in our cat?

- Nervous licking, excessive grooming.

- Nervous licking, often accompanied by looking away.

- Sweaty pads - traces may be visible on furniture, the floor, feet are visibly wet to the touch.

- Hypersensitivity to external stimuli, to sounds (sometimes an innate feature, it needs to be differentiated).

- Hair loss (heavy hair loss) and frequently the appearance of dandruff.

- Increased, intense rubbing, sometimes intense purring - an attempt to calm down.

- Vocalization - this is a very serious symptom.

- Dilated, round pupils that fill almost the entire eye.

- Hiding, too much calmness, too much "sleep" - the cat is constantly alert with rotating ears.

- Body stiffening, muscle tension.

Stress and disease

Illness, discomfort or pain are also sources of stress. The symptoms of pain in a cat are primarily behavioural symptoms. These include:

Change in activity level



Change in the daily routine




Poor condition of the coat (the cat stops grooming)

Too much cortisol reduces the production of digestive enzymes. Their smaller amount causes poorer digestion of food and thus worse absorption of nutrients by the intestines. This, in turn, leads to nutritional deficiencies and, in the long term, to such ailments as anaemia (iron deficiency, vitamin B6, B9 or B12), osteoporosis (calcium or magnesium deficiency), colds (zinc deficiency or vitamin C and D). These ailments, in turn, make the body work worse, make the cat feel unwell and stressed.

A disease, some undiagnosed chronic inflammatory process is also stress! We then have a real vicious circle, because stress is caused by pain, which evokes stress => health deteriorates, because cortisol has an immunosuppressive effect = »the body is unable to cope on its own, health deteriorates even more => stress increases.

Cats are wonderful but extremely fragile creatures. Since they do not like to admit their weaknesses, prepared in the course of evolution that they must always rely only on themselves, the signs and signals of stress and discomfort are very discreet. It is worth learning their mysterious world, as nothing is a greater joy for every cat owner than a happy, relaxed and healthy cat.

Dorota Szadurska
Cat Behaviour Counsellor and Therapist
Post-Diploma Graduate in Animal Psychology (Polish Academy of Sciences)
Member of The International Society of Animal Professionals