Stress-related diseases like heart attacks are becoming common. Science is trying to understand how the human body copes with stress
stress - always recognised by alternative medicine, ancient Indian practitioners and yogis as a cause for disease, is only now being studied by modern scientists and doctors for its implications for the human body. Advances in the understanding of the neurobiology of stress open vistas for preventive medical treatment including drug therapy and in the more distant future, gene therapy.
"The proper acti-vity and effects of the stress system in the resting state and appropriate activation and effects in the stress state are important both for normal daily functioning and for coping with superimposed stress," explains G P Chrousos, a stress expert at the us-based National Insti-tutes of Health ( nih ).
Unbridled stress upsets the normal functioning of vital systems in an individual.Disturbance to the digestive process and suppression of sexual behaviour, over-activation of emotions, inhibition of immune reaction among others are a result of stress. In an age when keyed-up profe-ssionals take the aid of traditional rela-xation techniques like yoga and meditation to unwind themselves, science lifts the veil of mystery from the face of the complex phenomenon called stress.
Hans Selye, the famous Hungarian stress expert, declared once that "stress is life and life is stress". Meaning that stress invades our lives fully. According to stress experts life is a dynamic process with stressors of various hues hitting us all the time. The extrinsic or intrinsic forces, out to disturb 'homeostasis' - the equilibrium of life - are termed stressors. These put stress, the extra de-mand, on the physical and mental resources of an individual whose system struggles to cope with it.
Interestingly, stressors are consi-dered neutral in nature. Factors which stress one person may not stress another, and things which cause stress at one point in a person's life may not at another point. So it is the reaction to a stressor that defines whether it is 'stress' or 'distress'. In general, vulnerability to stress depends on the personality and disposition, based on the genetic constitution and environment, of an individual.
Suggestion that stressors effect just the mind is a fallacy. Scientific research reveals that stress targets mind, which in turn triggers a host of physical reactions, finally coming off as behaviour. This vital mind-body link constitutes the basic fabric around which the whole mechanism of stress is interwoven. If either of the duo fails to cope up with stress, there is a break down in overall health. The mechanism is so intricate that sometimes even the conscious mind remains unaware while stress eats into the vitals of the body.
And how does an individual survive onslaughts by stressors? By adapting to changes in the environment at the mental and physical levels. The mind responds to stress either positively or negatively. As it forms the first line of defence against stressors, right perception of a problem helps in managing stress successfully. From the mind, signals are passed to the body, which copes by changing its biochemistry. It has been found that human beings have a complex biological system that maintains homeostasis both at the resting and stressful situations.
Called the stress system, it includes components of central and peripheral nervous systems. At the resting state, it performs key functions of the body like maintaining cardiovascular tone, respiration, intermediary metabolism and regulation of hunger and sexual arousal. And, at the stress state it responds by switching on appropriate biochemical reactions.
A normally functioning stress system is able to integrate a large number of incoming signals, successfully dam-pening their effect. However, when there is an imbalance between demand and coping skills, the body gears it-self for a fight or flight reaction. Physiological changes take place instantly to survive the hostile threat. Breathing becomes faster, heart beat steps up and perspiration increases. Fat and sugar reserves of the body break down to provide energy to cope up with the emergency. Significantly, secretion of stress hormones like cortisols, inhibits immune responses of the body. Digestion and sexual urge slows down, blood pressure increases and the anxiety level shoots up.In other words, the same systems that keep you going begins to close down. As the brain switches off the panic signals, the chemicals are metabolised and the system returns to normal. However, if stress is recurrent or if the person fails to adapt to stressors, disabling illnesses result.
According to experts like Chrousos, chronic stress leads to a range of emotional, behavioural and physical aberrations. It can cause emotional reactions like irritability, anger and aggression, anxiety, a feeling of hopelessness, depression, mood swings from elation to despondency and withdrawal from people. Behavioural maladies like poor sleeping habits (insomnia), excessive drinking, excessive eating or loss of appetite take root. Ironically, stress causes these abnormal patterns which in turn perpetuate its existence.
At the physical level, chronic stress lowers both resistance to illness and intensifies its impact. Under prolonged stress, the body's immune defences are considerably weakened. This is because of a group of hormones secreted by adrenal glands in response to stress. Called cortisols, the hormones in-duce immunosuppression. Function-ing mainly as immunoregulators during inflammation, that is any physical or chemical injury to tissues, cortisols during periods of stress disadvantage the immune system.
Owing to an upsurge in levels of hormones and chemicals in the body coupled with a weakened immune system, a host of diseases take root in stressed people. For instance, under chronic stress, glucocorticoids, a class of cortisols that induce fat accumulation in the body, causes high blood pressure and damage to arteries leading to heart attacks and strokes. Further, high levels of glucocorticoids during stress explains why stressed people are prone to become obese. Loss of insulin during stress response results in diabetes and other hormonal imbalances like thyroid disorders. Osteoporosis, arthritis and vulnerability to fractures can result from a poor reparative process while chronic skin disorders and allergies can become recurrent. Scientists have found that stressed people develop ulcers, experience loss of libido and get asthma.
Vulnerability of an individual to stress induced diseases depends mainly on the sensitivity and memory of the stress system. And as Chrousos informs, "people who are highly sensitive to stress, fall victim to diseases like anxiety disorders, depression, alcoholism, and substance abuse, eating disorders, personality and conduct disorders and psychosomatic diseases like irritable colon, low back pain, insomnia more easily than others." According to statistics published in The Global Burden of Disease (Harvard School of Public Health, 1997), the largest projected increase in mortality is for cardiovas-cular diseases which is expected to increase from 14 million deaths in 1990 to 23 million in 2020.
With this, cardiovascular diseases, more often caused due to stress , would account for more than one-third of all deaths world-wide. Figures for India also show that cardiovascular deaths will account for more than one-third of all deaths in the country between 1990 and 2020.
Interestingly, our tryst with stress begins much before we step into this world. Researchers have found that even the foetus experiences physical stress. According to Katia Karalis and Joseph A Majzoub of the Harvard Medical School, us , "extremes of stress on the foetus can have profound and permanent effects on the basal and the stress responsive activity of the stress system." Emotional and physical stress in childhood has a similar impact. With increase in age, the vulnerability to stress decreases. How-ever, stressors of sufficient magnitude and duration can have profound effects in adults also.
Significantly, diseases are caused not only due to excessive activity of stress system, less than normal activity also brings trouble. It has been found that when one or more components of the stress system are hypoactive, fatigue and irritability sets in.
Summing up the dynamics of stress, Chrousos states, "it is certain that genetic abnormalities of the stress system is responsible for a large portion of human misery. It is also certain that prenatal stress and a deprived, exploitative or hypercritical childhood environment perpetuates the misery by constitutionally affecting the stress system of individuals, who then themselves, by begetting children and exposing them to similar toxic conditions, become a crucial link in an ever-continuing vicious cycle. Apart from finding scientific solutions, a parallel crucial effort should be to break the sociobiological vicious cycle of stress that plagues humanity and causes immeasurable losses."
With the stress of life becoming more intense in the modern world owing to a general degradation of environment, personal values and beliefs, an effective stress management regimen would call for a holistic approach. Experts feel that changing personality and how to relax through time tested techniques could help one to adapt effectively to changes in life and managing pressures of daily living.
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