Stress, a word from engineering world :
when some force is applied to an object that is beyond the capacity of object to absorb and from start to breakdown is matter of pressures intensity.
So is it in humans except humans have two additional tools
1. Managing stress by changing neuro biology of mind ,and
2. Improve the bearing capacity of stress by use of essential oils ,herbs.
These three notes will be about what we know about stress. What it can do with human body and how we can manage it.
Stress and Health: The Basics
In order to survive, the human body is required to continually adapt to the changing internal and external environment. At its most basic level this is known as homeostasis, whereby the human body tightly regulates its internal physiological states (e.g., body temperature, oxygen supply etc.) to keep us alive. In order to maintain homeostasis, our body releases hormones (e.g., cortisol, adrenaline, and noradrenaline) and switches on the autonomic nervous system (ANS) and the central nervous system to allow us to adapt and respond to day-to-day activities (some of which may be stressful). The release of these so-called physiological mediators (cortisol, adrenaline, and noradrenaline) and changes in immune and metabolic parameters (known as allostatic (Sterling & Eyer 1988) are protective and adaptive as long as they switch on and switch off in a balanced way when an environmental challenge or stressor is no longer present. However, when this fails to happen and the physiological response is maintained overtime, it can become damaging for our health and well-being.
McEwen (1998) proposed the concept of allostatic load to refer to the wear and tear that the body experiences due to repeated and long-term exposure to stress. Moreover, he suggested that allostatic load is characterized by the inefficient switching on and turning off of what he called stress mediators and, in some cases, to the failure of those mediators to mount an adequate response when required (e.g., if the body releases too little or too much cortisol when faced with an acutely stressful encounter). More broadly, McEwen (1998) proposed that the long-term impact of exposure to stress affects the body at the cardiovascular, metabolic, neural, behavioral, and cellular levels and increases the risk of developing disease because the bodily systems stop working effectively ( McEwen & Seeman 1999). Most recently, (McEwen 2018) has discussed the concept of allostatic overload, which describes the harmful effects of stress on our biological systems when a host of stress mediators are released to help us adapt but their excessive, prolonged, and repeated overuse and dysregulation can ultimately lead to damage. At its core, allostatic overload reinforces the notion that stress affects multiple biological systems and that these systems interact with one another to adapt and respond to changing environmental demands that are perceived as stressful.
The Stress Response
Broadly speaking, two systems are activated when we experience stress. The first and easiest to activate is the sympathetic–adrenal–medullary (SAM) system. The second is the hypothalamic–pituitary–adrenal (HPA) axis. When an individual is suddenly under threat or frightened, the brain (the amygdala, then the hypothalamus) instantly activates the ANS to send a message to the adrenal glands to trigger the release of noradrenaline, which in turn activates the internal organs. This is the basic ANS sympathetic response to threat. However, at the same time, the adrenal medulla releases adrenaline, which is rapidly transported through the bloodstream to further prepare the body to respond. This system is known as the SAM system response. Within seconds adrenaline and noradrenaline have the entire body on alert, the so-called fight-or-flight response. As a result, breathing quickens, the heart beats more rapidly and powerfully, the eyes dilate to allow more light in, and the activity of the digestive system decreases to permit more blood to go to the muscles. This effect is both rapid and intense.
In addition to the SAM response, when an individual experiences an event in their environment that they perceive as stressful, the hypothalamus releases a peptide hormone called corticotrophin releasing factor (CRF). Once released, CRF is transported in the blood supply to the pituitary gland, where it stimulates the release of adrenocorticotrophic hormone (ACTH). Subsequently, ACTH travels through the circulatory system to the adrenal cortex, where it stimulates production of the glucocorticoid cortisol, the so-called stress hormone. One of the central functions of cortisol is to increase access to energy stores, increase protein and fat mobilization, and decrease inflammation. Therefore, when an individual experiences stress, the surge in cortisol triggers the release of excess energy stored in the muscle and liver as glycogen, which is then broken down into glucose ready for utilization by the muscles and the brain. However, it is important to bear in mind that cortisol is a complex hormone and has multiple roles beyond the stress response (McEwen 2019). As discussed, latter, cortisol plays a key role in regulating circadian rhythm by influencing genomic and nongenomic cellular and molecular mechanisms.