Stress is perhaps, the most pervasive feeling of the modern-day lifestyle and yet, it is as old as life itself. Stress is the brains response to sensory stimuli, (anything that is, or perceived as, dangerous or life-threatening), this occurs naturally-nonconsciously, i.e. outside of your conscious awareness. In addition to this sensory stimulation, memory records the narrative of these types of events. This simply means the sensory stimulus has a fast and effective shortcut (memory) to the desired or undesired outcome, meaning, it happens lightning fast! However, just to confuse things a little, the feelings that we associate with being stressed are something else entirely. The physical feelings of stress are actually a part of several separate brain systems working together and independently. Collectively the awareness of the subjective experience of fear is fairly unique to humans. For us, this means it is actually possible to be (dis)stressed without having any conscious awareness of it! It also means that we may be unaware of the specific causes of our distress. This lack of conscious awareness can affect our behaviour in ways which may allow us to believe that others are the source of our problems? Technically, I call this, 'if it wasn't for you syndrome,' however, they may just be responding to what they see as our dysfunctional behaviour! Overreacting in ways that are out of context or too severe, i.e. above and beyond what would be a reasonable response etc. are characteristic traits of a chronically stressed person. As is tardiness, making more mistakes than normal, poor judgments, bad decisions or irrational emotional responses etc.
Another aspect of what we call stress is anxiety. Anxiety is the anticipation of danger or something fearful. But no matter whether we are suffering from stress (an actuality) or anxiety (a possibility), the system behind these experiences is the same. It is the fight or flight, stress response. This is activated in the brain by the anterior pituitary gland, which stimulates the HPA axis (hypothalamic-pituitary-adrenal axis), releasing cortisol into the bloodstream. Another system involved is the sympatho-adrenomedullary system, which releases adrenaline and noradrenaline, making the heart beat faster. It is also worth mentioning the Locus Coeruleus (LC), a small structure in the brain stem, which also plays a role in mediating the stress response. The LC also plays a considerable role in mediating the way our body responds to stress, both emotionally, via the sympathetic nervous system. It also influences us cognitively through higher cortical structures, e.g. the prefrontal cortices, cingulate cortex and the reward pathways. This is important because the LC is the main producer of noradrenaline (norepinephrine) in the brain. During sleep, PGO waves, precede REM sleep (more about this below) and REM almost halts all production of noradrenaline in the brain, effectively creating a more peaceful brain!
The stress response (fight or flight), which occurs within a few milliseconds, happens outside of and before we could possibly have conscious awareness of it. However, it has to be said, that under normal circumstances, this system works extremely well to keep us safe and has no known long term effects. Of course, there is a caveat to that! The caveat being, we should only experience it when we are in danger, under the threat of attack or if there is potential for injury. When we become chronically stressed (unless we're in a dangerous environment, e.g. Iraq, Syria), the system malfunctions, we become hyperaroused, overreactive and snap at the slightest thing!
Some examples of modern life stressors are:
1. you are in debt and interest rates rise, making an already bad situation worse
2. you're in your late 40'/50' etc. and get retrenched and feel threatened by younger people in the job market.
3. You become obsessed with the amount of negative news you hear every day but look at the news sources even more ( confirmation bias)
4. you are in line for a promotion and a someone new, maybe a colleague, that everyone likes, including your boss, shows up and you feel threatened
5. you grow distant from your family and believe your spouse or partner may be cheating on you
6. you begin to get feelings of paranoia and believe people are out to get you
7. you start having some health issues, e.g. forgetfulness (which is a symptom of stress) and think you may have the onset of dementia
8. you seem to have more arguments than usual and people start avoiding you
9. you may have an undiagnosed condition or suspect you have one (hypochondria) etc. etc.
These are just a few ways that modern life affects our mental health but there are many more variable symptoms of stress. This can be paradoxical because the stress response follows a known and predictable pathway (as mentioned above, the HPA axis). However, the way we each experience and respond to the stress response can take many forms and affects us in many different ways.