Practice in Clinical & Health Psychology
Chronic Stress & Illness

of Chronic Disease

By Dr. Horst H. Mueller, RPsych, CRHSPP, FBCIA-EEG
Private Practice in Clinical & Health Psychology


Whether from a charging grizzly bear on a mountain trail, or a pending deadline to file some critical legal documents, the body’s response to stress can be both helpful and harmful. The stress response gives us the strength and speed to ward off or flee from an impending threat. But when the stress response persists, it can put us at risk for life-threatening diseases.

A threat to your life or safety triggers a primal physical response from the body, leaving you breathless, heart pounding, and mind racing. From deep within your brain, a chemical signal speeds stress hormones through the bloodstream, priming your body to be alert and ready to run or fight. When the threat ends, hormonal signals switch off the stress response and the body returns to normal.

But in our modern society, stress doesn’t always let up. Many of us now harbour anxiety and worry about daily events and relationships, we are constantly pressed for time, and the little daily hassles just keep piling up. Stress hormones continue to wash through our system at high levels, never leaving the blood and tissues. And so, the stress response that once gave our ancient ancestors the speed and endurance to escape life-threatening dangers runs constantly in us in our modern life and never shuts down.

Research now shows that such long-term activation of the stress system can have a hazardous, even lethal effect on the body, greatly increasing the risk for obesity, diabetes, heart disease, depression, and a variety of other diseases.

The Brain’s Response to Stress

In response to a perceived threat or danger, a part of the brain called the hypothalamus-pituitary-adrenal (HPA) system is activated. The HPA systems trigger the production and release of steroid hormones (gluccocorticoids), including the primary stress hormone, cortisol. Cortisol is very important in marshaling systems throughout the body— including the heart, lungs, circulation, metabolism, immune systems, and skin— to deal quickly with the threat.

The HPA system also releases certain neurotransmitters (chemical messengers) called catecholamines, particularly those known as dopamine, norepinephrine, and epinephrine (also called adrenaline).

Catecholamines activate an area inside the brain called amygdala, which triggers an emotional response to the stressful event— most often anxiety or fear.

During the stressful event, catecholamines also supress activity in areas at the front of the brain (prefrontal and frontal lobes) concerned with short-term memory, concentration, inhibition and rational thought. This sequence of mental events allows a person to react quickly to threat or danger, either to fight or flee, without too much second-guessing. It also hinders the ability to handle complex social or intellectual tasks and behaviours during the stressful period.

On the other hand, neurotransmitters at the same time signal the hippocampus area of the brain to store the emotionally-loaded experience in long-term memory. These emotionally-loaded memories are often related to the development of Post-Traumatic Stress Disorder.

Psychological Effects of Chronic Stress

Research strongly suggests that the inability to adapt to stress is associated with the onset of depression and anxiety. The repeated release of stress hormones produces hyperactivity in the hypothalamus-pituitary-adrenal axis and disrupts normal levels of serotonin— the brain neurotransmitter that is critical for feelings of well-being. Certainly, stress diminishes quality of life by reducing feelings of pleasure and accomplishment, and often threatens relationships.

Heart Disease

Stress can greatly influence the activity of the heart through its activation of the sympathetic branch of the autonomic nervous system. Stress increases the pumping action and rate of the heart while simultaneously causing the arteries to constrict, thereby restricting blood flow to the heart. The emotional effects of stress alter the heart rhythms, which can pose a risk for serious arrhythmias in some people. Stress causes blood to become thicker and stickier, increasing the likelihood of artery-clogging blood clots. Stress also impairs the clearance of fat molecules in the body, raising blood cholesterol levels. In women, chronic stress may reduce estrogen levels, which are important for cardiac health. Stress is also associated with increases in blood pressure and the development of hardening of the arteries.

Numerous studies show that chronic stress and negative emotions such as anger, hostility and cynicism are associated with increased risk of cardiovascular disease and are actually as powerful predictors of the development of cardiovascular disease as the better known lifestyle predictors of smoking, obesity and lack of exercise.


Research shows that persons who have a more intense response to stressful situations, such as waiting in line or problems at work, are more likely to have strokes than those who do not report such distress. Stress-associated increases in blood pressure increase the risk of stroke.


Chronic stress appears to blunt the immune response and increase the risk for infections and immunizations. Persons with high chronic stress show elevated white blood cell counts and are more vulnerable to catching colds, flu, and numerous other illnesses.

Immune Disorders

Many autoimmune diseases such eczema, lupus and rheumatoid arthritis are aggravated by stress. While short-term stress appears to have no relationship to multiple sclerosis, chronic stress does appear to be a major risk factor for flare-ups.

Gastrointestinal Problems

The brain and the intestine are strongly related and mediated by many of the same hormones and nervous system. It should not be surprising then that prolonged stress can disrupt the digestive system, irritating the large intestine and causing diarrhea, constipation, cramping, bloating, and gas. Sleep disturbances due to chronic stress can greatly exacerbate irritable bowel syndrome. Chronic stress is known to play a significant role in the development of irritable bowel syndrome, peptic ulcers, inflammatory bowel disease, and colitis.

Eating Problems

Stress can cause both unwanted weight gain or weight loss. Stress hormones can lead to unwanted weight gain by causing carbohydrate cravings as well as disrupting the normal fat storage cycle of the body. On the other hand, stress can trigger hyperactivity of the thyroid gland, stimulating appetite but causing the body to burn up calories at a faster than normal rate. Elevated stress hormone levels have been observed in persons with eating disorders such as anorexia or bulimia.


Chronic stress has been associated with the development of insulin resistance, a condition in which the body is unable to use insulin effectively to regulate blood sugar levels. Insulin resistance is a primary factor in the development of Type II diabetes. Stress exacerbates diabetes by raising blood levels of the stress hormone cortisol, which regulates insulin and blood-sugar levels.

Diabetics who are chronically stressed experience much more erratic blood sugar readings through the day and have greater difficulty in stabilizing their blood sugar levels through diet and medications alone.


Chronic pain caused by arthritis and other conditions can be intensified by stress. Psychological stress is well known to play a significant role in the severity of back pain and many other chronic musculoskeletal pain syndromes. As well, tension-type headache episodes are strongly associated with stress and stressful events. Many persons have a predisposition to store psychological and emotional stress in the body as muscle tension. For individuals with myofascial pain syndromes, stress— through increased sympathetic nervous system arousal and the release of noradrenaline in the muscles— will increase the sensitivity of painful trigger points and increase the experienced pain.

Sleep Disturbances

The tensions of unresolved stress frequently cause insomnia, or awakening in the middle of the night or too early in the morning. In fact, research has shown that stress hormones can increase during sleep in anticipation of a specific waking time.

Memory, Concentration and Learning

Research shows that the immediate effect of acute stress is to impair short-term memory, particularly verbal memory. Chronic stress results in loss of concentration, easy distractibility, inattentiveness and a tendency toward becoming accident-prone. Chronic stress actually causes a shrinking of the hippocampus— a part of the brain that plays an important role in the storage of memory and learning.


Chronic stress is endemic in our society but it can be managed and its negative effects can be greatly reduced. While basic lifestyle changes such as getting more physical exercise, sleeping at least 7-8 hours every night, and eating healthier (e.g., more fruits and vegetables, and less saturated fats and sugars) will definitely help you to stay healthier longer, research has shown that learning to manage the body’s response to stress and reduce the dysfunctional thinking that often maintains stress can have just as profound an effect on preventing chronic disease. The person who continues to worry about their job while they are exercising or eating a healthy meal will not get the same benefits from these healthy lifestyle changes as a person who also knows how to manage their thinking so as to reduce anxiety and other negative feelings.

Biofeedback training can be a powerful tool for learning how to better manage the body’s response to physical and mental stress. Similarly, taking a course or workshop in stress management can be an excellent way to learn about some of cognitive, lifestyle, and nutritional aspects of better managing stress in your life.

A particularly powerful combination of therapies for persons having difficulty in managing their stress is Cognitive-Behavioural Therapy (CBT) and Biofeedback Therapy (BT). CBT focuses on changing the beliefs, attitudes, thoughts and behaviours that are causing greater perceived stress and preventing more effective coping whereas, BT focuses on teaching the individual how to better control their physiological response to stressful situations.

A good example of a relatively simple and very effective stress coping strategy that combines cognitive and psychophysiological approaches is the HeartMath Institute’s use of Heart Rate Variability (HRV) biofeedback training together with training in positive or appreciative thinking to give people a method of coping with stress throughout the day. [GOTO:  ]

Living in a modern industrialized society such as we have in Canada is stressful to the human psyche and body. A growing number of Canadians’ daily lives are constantly stressful without break. Everyday niggling hassles and constant time pressure is slowly killing us. There is no shame in seeking out professional help from certified counsellors or psychologists who are knowledgeable in stress management techniques and can help you to better manage the stress in your life and better control your physiological response to stressors.

For more information on biofeedback and certification of professionals in biofeedback, GOTO:  and  


Recommended Reading

Childre, Doc & Rozman, Deborah (2005). Transforming Stress. The HeartMath Solution for Relieving Worry, Fatigue, and Tension. Oakland, CA: New Harbringer Publications.

O'Conner, Richard (2005). Undoing Perpetual Stress: The Missing Connection Between Depression, Anxiety and 21st Century Illness. New York, NY: Berkley. 

Sapolsky, Robert (2002). Why Zebras Don’t Get Ulcers. An Updated Guide to Stress, Stress-Related Diseases, and Coping. New York, NY: W.H. Freeman & Co.

Scaer, Robert (2001). The Body Bears the Burden: Trauma, Dissociation, and Disease. New York, NY: Haworth Medical Press.