Stress remained unrecognised for long in medical literature as a cause of many diseases due to difficulties in quantifying its levels through specific markers. We now recognise that stress plays a major role in influencing our behaviours and biology in many ways and can lead to several health disorders. It can raise blood pressure, increase blood clotting, cause heart beat irregularity, damage heart muscle, lead to diabetes, depress immunity, cause skin and bowel disorders, accelerate ageing and impair brain function. It can precipitate heart attacks or strokes and lead to sudden death.
Yet, stress is not always pathological, to be perceived negatively. It is essentially a physiological response, meant to protect us. However, it can be counterproductive and damaging to health if excessive or prolonged. It is important to understand the pathways and provocateurs of stress if we are to influence it in a manner that enables our survival without eroding our health and well-being.
Hans Selye, who coined the term ‘stress’ in 1936, defined it as “the non-specific response of the body to any demand for change”. It is the collective term to describe the sum total of the body’s responses to a challenging situation. The challenge may be physical, mental or emotional. It can be a stimulating challenge to your creativity or a damaging reaction to a real or perceived threat.
The stress response is an evolutionary survival mechanism against possible dangers that are posed by a changing environment. When our cave-dwelling ancestors ventured out to hunt for food, they also faced the danger of being attacked by a predator. The choice was between ‘fight or flight’. Either way, the body had to be prepared.
In a stress response, the ancestor’s body revved up the sympathetic nervous system and the adrenal glands. The raised levels of adrenaline in the blood increased the heart rate and blood pressure, to supply more blood to the actively exercising muscles as the ancestor fought or fled. Steroid hormones were poured into the blood and raised blood sugar levels to supply the active muscles and the brain, which had to make quick decisions. To preferentially supply blood to the brawn and the brain, blood supply to other organs decreased, especially to the stomach and intestines. The tongue became parched. Sweating increased to dissipate heat from contracting muscles. Pupils dilated to extend the ambit of vision to spot the danger. Blood clotting mechanisms were activated, lest there was injury during the fight or a fall while fleeing.
When catapulted into modernity, these acute stress responses become counterproductive, if frequent and prolonged. When a student is criticised by the teacher in the classroom or an employee is berated in the office by the boss, usually there can be no ‘fight or flight’, only suppressed anger, hidden hurt and spillover of negative feelings into the rest of the day. That is not a physical threat but still a threat to self-esteem. It evokes a stress response without a physical release. One cannot also fly away when stuck in a terrible traffic jam. The internalisation of stress response then hurts the body.
To cope with stress, we must redefine our threats to raise the threshold for threat perception and also find a physical release mechanism. Sleep, meditation, music, reading, pleasant interactions with friends and family, light entertainment, books, nature walks and pets can reduce the threat perception by diverting the mind to more pleasant stimuli. Sports, brisk walking or jogging can provide physical release, to substitute for the fight or flight muscular action. Yoga combines meditation for mental tranquillity with the physical activity of asanas. Some people turn to religion, believing that there is a higher power that will protect them from danger. All of these actions tend to tune down threat perception or provide a physical release to the stress response, so that the body is protected from harm.
Chronic stress is damaging to health. It causes inflammation, which can damage many organs. Acute stress can be protective when you have to respond to an immediate danger (like a speeding car rushing at you) but can also be harmful when excessive. Anger is a dangerous source of acute stress that often does not end well. John Hunter, a famous British surgeon-anatomist of the 18th century, prophetically said “my life is forfeit to any rascal who chooses to annoy me”. He died during a stormy hospital board meeting where he lost his temper. We now know that severe acute stress can fissure plaques in coronary arteries by raising blood pressure suddenly and precipitate large clot formation on the fissured surface to block blood flow.
Stress is like a musical string instrument. If the strings are too lax, we can’t make music. If the strings are too taut, we can’t make good music either. We need the right amount of stress at the right time.
Dr K Srinath Reddy
Cardiologist, epidemiologist & President, Public Health Foundation of India
(ksrinath.reddy@phfi.org)
(Views are personal)