Stress has become a word used colloquially in many circumstances of minor or major complaints. An annoying person is a ‘stress’, work is ‘stressing’, worries are ‘stress’, the weather can be ‘stressful’ etc. It is a common saying but it is all also anatomically true; all these are real stresses, or better, stressors. The use of the word stress in biology and medicine is precise and indicates a
‘response to any threat to life or wellbeing’
(therefore the pressure at work would be a threat and the persistent rain another one).
Stress can be brought by either
physical strain (the stressor): a long run, exposure to toxins or environmental poisons, heat or cold;
or by emotional strain: a divorce, a move, a marriage, bereavement, academic pressure, losing a job, a job itself!
The physical and physiological reaction is identical in the two cases. Stressors of both types elicit a sequence of reactions by the body, which is called the “stress response” or “fight-or-flight response”. We learned this type of reaction when humans had to face attacks from ferocious predators or had to survive in face of extreme conditions (life in a cave, hunting in a jungle). Although most humans don’t face such threat anymore, the reaction to modern life stressors (traffic jams, playing a rugby match – or sometimes just watching it!-, buying a house) has remained the same.
The flight-fight-freeze response is initiated by nerve impulses from the hypothalamus (a part of the brain that controls most involuntary responses like body temperature, hunger, fatigue, attachment behaviors etc.); such nerve commands reach the adrenals (glands that sit on the kidneys) directly, stimulating release of adrenaline and noradrenaline, which increase heart rate, blood pressure and breathing rate: they get the body ready to fight or to run.
Impulses from the hypothalamus reach also the endocrine system (hormones), via the hypothalamus-pituitary tract, to stimulate the pituitary gland (or hypophysis) and the adrenals again. The adrenal glands, stimulated both by the nervous system and by hormones, release cortisol (the major stress hormone), which, along with the growth hormone released by the pituitary gland, stimulates catabolism or production of glucose, aminoacids and fatty acids from fat stores and proteins to provide the necessary energy for movement (fight or run), repair or defense.
The pituitary gland also promotes the secretion of thyroid hormones T3 and T4 that increase use of glucose as well, while the insulin response (insulin is the hormone needed to store glucose inside the cell) is shut down so that increased sugar can remain in the blood ready for energy need. Pancreatic release of insulin is thus depressed.
All these reactions aim to put the body in action with increased breathing, increased heart rate, increased muscular contraction needed for the fight or for the flight in front of the threatening predator or office boss or running competitors; at the same time the activity of the digestive, urinary and reproductive systems, quite useless in those situations, is depressed.
Stress in moderation is not harmful and can be necessary as an incentive in some actions (positive stress or eustress), like getting ready to win a match.
However, when stress is prolonged, repetitive and not dealt with, it can become harmful and lead to diseases: constant stress in fact brings hormonal changes in the body, lowers the immune functions and can lead to many diseases including auto-immune diseases.
It is the individual response to the stressor that can make a difference between a healthy happy life and a miserable life threatened by chronic illness. This is because it is not the type of stressor that initiates a response but the “perception” of such a stressor by the individual. The perception of an experience determines how we feel when it is happening and how our bodies will be affected. What is terribly difficult to endure for some person can be easily managed without consequences by someone else.
Since constant or repetitive stress can have adverse effects on the body, in order to avoid stress-induced illnesses one should become more relaxed about life and always try to see issues in perspective. Since avoiding stress is rare or impossible, it is important for all to apply measures to release the tension: deep breathing, relaxation techniques, massages, cardiac coherence etc.
How does stress cause disease? Stress has impact on the nervous system, the immune system and the hormonal system. In an emergency situation immediate responses from these systems are needed, but in an unnatural prolonged state of stress they harm the individual. A physical or psychological stress affects the functioning of cells and can have long-lasting influences on physiology and behavior.
Impact on the nervous system: prolonged or repetitive stress can lead of physical changes in the brain, such as shrinking of the amygdala (center of emotions, decision making, memory) or the hippocampus (memory). Learning, memory and behavior are thus affected.
Impact on the immune system: it is well accepted and understood how a psychological stress is directly correlated to the prevalence of diseases such as infections. The immune cells have receptors for the hormones released during the stress response by the adrenal glands, the pituitary gland and the autonomic nervous system: cortisol, adenocorticotropic hormone, endorphins, noradrenalin, growth hormones, prolactin all influence the immune system. This explains the mechanism of the direct influence of stress on the immune system functioning. Cortisol triggers an increased “innate immune response” represented by inflammation, a high allergic response, an increase in viral infections and a higher cancer risk. These are responses that you do not wish on a long term.
Hormonal system: a continuous stress or a frequent presence of even smaller stresses drain the adrenal glands from which the main stress hormone, cortisol, is released. Prolonged stress can also lower the level of sex hormones like oestrogens. Pancreatic production of insulin is interrupted and this, on the long run, can lead to diabetes type 2.
As many as 80% of all major illnesses have been related to stress as a contributor.
Chronic stress causes:
wasting of muscles, suppression of immune system (by cortisol, which suppresses part of the immune system), generation of auto-immune diseases (like rheumatoid arthritis, lupus, multiple-sclerosis), cancer, hyperlipidemia (high fat content in the blood and wrong types of fats), atherosclerosis, increase of cholesterol, hypertension, hyperglycemia, diabetes mellitus, abdominal obesity (metabolic syndrome), osteoporosis, mood-behavioral changes, ulceration of GI tract (peptic ulcer, liver damage, irritable bowel syndrome, and ulcerative colitis and Chron’s disease which are precursors of colorectal cancer), insomnia, anxiety, depression.
Stress is a significant factor also in the birth of certain psychiatric disorders such as depression and anxiety.
Anxiety is one of the most serious emotional manifestations of stress and is caused by expectations of anything that threatens a person’s body, job, loved ones, values. It occurs in situations perceived as uncontrollable or unavoidable, but that are not really so. It is a state of inner apprehension, often accompanied by nervous behavior, like pacing back and forth, foot tapping, teeth grinding etc. Anxiety can also be a response to a past mismanaged stress.
Symptoms of stress are
high blood pressure, neck-ache, backache, muscles tension, muscle twitching, being unable to sit still or relax, fatigue, insomnia, lack of concentration, teeth grinding, nail biting, suppressed anger, feeling unloved, lack of self-esteem, low sex drive, irritability, tearfulness, loss of appetite or overeating, constant anxiety, frequent infections, allergies, blood sugar disturbances appearing with irritability and sugar cravings.
As many as 77% of people in Western countries complain of stress, and many are related to work. Many young people (younger than 18 years of age) are affected by stress. Some people are stressed but they are not aware of it, but the consumption of their teeth for example is testimony of it. Alert!
Stress also causes body mineral changes: it causes sodium retention, which in turn increases blood pressure. Adrenalin also causes a loss of Mg, Ca, K and P. Also, during stress, nutrients are not efficiently absorbed. A nutrient deficiency is thus created with deleterious consequences for many organs. Many of the diseases related to stress are not due to stress alone but to the loss of nutrients: vit C, K, P, B vits.
Susceptibility to stress: Some people are more at risk of chronic stress depending on their genetic pattern but also on their innate and acquired inability to face challenges and respond properly to increased demands from work, financial issues, surgery or illnesses, society, pollution (noise, atmospheric, toxins), allergies, etc. Nutrient deficiencies from other causes, like improper nutrition, ex lack of B vitamins or Mg, make an individual more at risk of succumbing to chronic stress.
Age, gender, social status, social support, religious/spiritual beliefs, personality traits, self-esteem, past experiences are all factors contributing to such susceptibility.
How to cope: Again, there are many tools that help in learning to managing and coping with repetitive stress:
* regular exercise, both low-intensity aerobic exercise to boost immunity, and physical practice that balances the immune system reactions and boost an antibody response (suppressed in stress condition): walking, jogging, biking, yoga, tai chi, chi gong;
* relaxation, breathing practice, like cardiac coherence or pranayama (yoga breathing exercises),
* meditation and
* massage are all useful tools that should be relied upon on a regular basis to improve the reaction to stressors.
The best care for the body is a quiet mind. Napoleon.
Brain Behav Immun. 2011 Oct;25(7):1305-15. doi: 10.1016/j.bbi.2011.06.005. Epub 2011 Jun 14.
Craft, J., Gordon. C., Tiziani,. A. et al. 2012 Understanding pathophysiology, Elsevier, Houston pub.
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