You often hear that ‘stress is bad’ and ‘not good for you’, but what exactly is it, and is it always bad for you?
For many years ’being stressed’ was considered a ‘state of mind’ – Fortunately these days what happens when you’re stressed (the “stress response”) is now better understood! Stress may be good for you – but not for extended periods – read on…
Stress is unusual in biological terms – although the causes can, and do, vary between what people find stressful (think anything from first date to being chased by a lion) it usually results in the activation of the same physiological mechanisms- the “stress response” but the stress response can result in different outcomes. This extremely complex pathway involves the nervous, endocrine and immune systems.
When we perceive something stressful (some people like first dates and lions…) the brain sends a cascade of nerve impulses through the body via the sympathetic nervous system. This increases processes in the body, through the release of the hormones adrenalin, noradrenalin and ACTH. Adrenalin and noradrenalin are partially responsible for the metabolic changes that occur during stress – including the rapid mobilization of glucose to provide instant energy to muscles (‘flight or fight’), and an increase in heart rate and blood flow. ACTH keeps the heightened response going via cortisol and glycogen. Cortisol initiates the breakdown of glycogen into glucose, and triglyceroles into fatty acids. Both glucose and fatty acids are used as energy sources, making the blood energy rich and ready for ongoing vigorous activity. Furthermore, cortisol inhibits inflammation. All of these responses are beneficial if a physical response is required (some people want to run from first dates and lions).
Endorphins are released and – with an impact similar to morphine, opium and heroin – the perception of pain is reduced. For a brief period (approx. 30 mins) the immune system is improved (due to the release of ACTH) but digestion levels drop (due to a reduction in stomach acid and reduced blood flow to the stomach).
A small amount of stress appears to be beneficial to brain function. Although not completely understood, it is thought that an increase in adrenalin and glucose facilitates the formation of memories and increases alertness and danger recognition.
And there you have it – the “stress response” is many responses – some bodily functions are increased, while some – generally those that are not immediately useful are ‘put on hold’. The stress response is a form of efficiency drive – there is no point worrying about producing children and digesting a three course meal if you may not make it through the next 10 minutes!
So, stress in itself is not bad and neither is the stress response! It is probably even downright useful when faced with a lion, but the stress response is designed to help you tackle immediate physical dangers – not long term psychological or emotional situations. If the stress in your life is more long term issues this may result in the stress response being ‘switched on’ for extended periods, which is not what it was designed for and which can have detrimental effects. These effects will be discussed in the next blog – When Stress Goes Bad.
Stress*- is ‘any factor that threatens the health of the body, or has an adverse effect on its functioning, such as injury, disease, overwork, or worry.’ (Oxford Medical Dictionary)