Our stress response is designed to mobilise the body’s fuel reserves – to convert them into a form suitable for immediate use. This extends to processes that provide fuel, along with extra oxygen required to burn it, aside from the organs most likely to need it – the brain and vital muscles.
When we are under stress, certain biological systems, such as growth and reproduction which, though essential, in the longer term, are not essential for immediate survival. For instance, the hormonal systems that regulate growth and reproduction are plumbed into the stress response and profoundly influenced by it.
Prolonged stress, for instance, hampers the secretion of the growth hormone and also the sex hormones. This acts as a mediator for one part of the nervous apparatus – called the sympathetic nervous system – which deals with the body’s housekeeping functions under normal conditions. It is, therefore, well placed for rapidly re-adjusting our priorities.
This is what happens during stress – your pulse, blood pressure, and breathing rate increase to help boost the supply of available energy. Think of an idiom – the pounding heart. Besides beating faster, under stress, it now pumps a greater quantity of blood with each beat.
The bronchial tubes dilate to facilitate the passage of more air with each breath. The blood vessels supplying the muscles now expand just as well. The palms of our hands and the soles of our feet start to sweat, primarily because a damp surface provides a better grip of things. Behavioural research says that this response evolved in our forebears – to help them manage in a world without shoes.
Now, as the pupils of your eyes begin to dilate to let in additional light and improve your vision, your mental alertness and reaction time are speeded up. However, when things go far beyond one’s control, the situation becomes terrifying for the other part of the nervous circuit – the parasympathetic system. This leads to involuntary urination and defaecation. Upsetting yourself in this way might be messy, but having an empty bladder and bowel could often be helpful when things get frantic.
In any stressful situation, our biological functions not vital for short-term survival are closed down. When this happens, long-term energy reserves in the form of stored fat are broken down into fatty acids and glycerol – this can be metabolised right away. In the meanwhile, carbohydrates stored in the liver are mobilised and converted into glucose, just as blood is shunted from the extremities towards the heart, muscles, and brain.
It’s at this point that the peripheral blood vessels narrow down – you get cold hands and feet. ‘Cold feet,’ a famed literary expression, takes place in anticipation of any unpleasant event. It is a typical stress response. This, in effect, leads to the shutting down of energy-consuming processes – the production of saliva. The result – a typical feeling of dry mouth, loss of appetite, and agitated bowels.
The stress response, when measured in terms of aiding survival, in a dangerous world, makes sense as a good thing. A physiologically aroused individual is better able to deal with life-or-death situations. We have evolved to respond to stressors in this manner. Also, there is nothing unusual, or weird, about finding threats to our health and well-being unpleasant and, therefore, seeking to avoiding them. However, it is a totally different thing if stress is triggered several times a day, under unusual circumstances, or for prolonged periods. This can lead to not just adjustment difficulties, but also health disorders. It is obvious that stress has psychological upshots as well as psychological triggers. It changes the way we perceive the world. It also affects our senses, memory, judgment, and behaviour.
To illustrate the point. It goes without saying that our nervous system processes sensory data. This is regulated by cortisol, the stress hormone. A high cortisol level is a distinctive facet of stress, attended by a decrease in sensory acuity, or the aptitude to distinguish certain weak stimuli with a ‘matching’ improvement in sensory insight.
The latter, as you know, enables us to make finer distinctions between disparate stimuli. While all our senses, including taste, smell, hearing, and balance, are affected, a person with high cortisol levels, for instance, will not be able to decipher the presence of a weak resonance – yet, they will be able to tell two somewhat different sounds apart, because of the heightened state of sensitivity that is aroused by stress.
Whatever the nature of our evolutionary origins, a readjustment in our sensory abilities makes good biological sense. What does this signify? To be able to make a fine judgment between relatively intense stimuli rather than detecting the presence of extremely faint stimuli, or signal. This is also a sign that tells us ‘what-is-as-it-is’ of a stressful situation.
It should also be remembered that several parts of the brain play a major role in processing all of this information. This includes the cerebral cortex and other higher centres of the brain. When your brain decides – consciously, or unconsciously – that all is not well, the hypothalamus is activated. The hypothalamus is the region of the forebrain and the source of several primary electrical and chemical signals which trigger the complete stress response in our body. The hypothalamus also regulates functions, such as eating, drinking, memory, and sensual pleasures.
When stress activity is evidenced, the reticular activating system, or network of cells, ‘jazzes-up’ your general level of stimulation and alertness – so as to make you more receptive to signals from your sensory organs. Example: inconsequential pains, or bodily sensations. So, there you are. When a difficulty is about to emerge, a prickly, or a gooey nose would not be able to distract, or befuddle your focus.
