Stress | Everything You Need To Know

Introduction | Impacts of stress on health | Two types | The signs and symptoms | Frequently Asked Questions

An image of a stressed man.

Stress is defined as the body’s response to perceived threats. Those threats, or stressors, could be internal – thought processes such as negative self-talk – or external – relationship problems or occupation pressure. Regardless of the cause, nearly everyone experiences it at some point in their lives.


But if stress is left to persist or just ignored, it could negatively impact your health. In this article, we will take a closer look at the many ways it impacts our health as well as the signs and symptoms.


How stress impacts health

Stress – also known colloquially as the ‘silent killer’ – adversely affects around 75% of people.¹ According to the World Health Organisation (WHO) stress has reached ‘epidemic’ proportions and costs the global economy hundreds of millions in lost productivity and medical care.


It has been estimated that ‘over 80 percent of visits to the doctor’s office in the developed world are for stress-related disorders’ (Dr Siegel, Psy.D 2014).


Contrary to common perceptions stress doesn’t merely cause irritability, mood swings, and stomach ulcers. Around 80% of all cases of depression originate from ‘stressful life events,’ (Bullmore, 2018, p.150).


This has led the WHO to predict that stress-induced mental disease will soon be the second leading cause of disabilities (Kalia, 2002).

The immune system

In addition to causing (or exacerbating) mental health disorders, the silent killer has been shown to suppress immune function.


In his book, Why Zebras Don’t Get Ulcers, Robert M. Sapolsky, who is a Stanford professor of biology and neurology and foremost researcher into the impacts of stress on health, talks about how it impairs immune function thus increasing our susceptibility to illness and disease – such as cancer.

States of chronic – or persistent – stress have been shown to inhibit digestion, reproduction, ovulation, and the general growth and repair of tissue (Sapolsky 1994).


This goes some way to account for why people suffering from chronic stress are more likely to get ill and develop disease; for their bodies, as Sapolsky colourfully puts it, ‘halts long-term, expensive building projects’ like manufacturing antibodies whose job it is to fight, amongst other things, tumour cells.


But the harm doesn’t stop there.

Mental health

If allowed to persist – which is typically called ‘chronic’ or ‘long-term’ stress – it can contribute to the decline in physical health. Researchers have linked chronic stress to some of the major modern health concerns such as type 2 diabetes, cardiovascular disease, and obesity (Harris et al., 2017; Song et al., 2019; Bullmore, 2018).


Furthermore, the silent killer can also harm the brain!

Impacts on the brain

Emerging research is showing how stress can exert a destructive influence at both a cellular and neurological level. For example, the stressed brain halts highly important ‘building projects’ such as birthing new neurons – called neurogenesis – while also impairing hippocampal function; the hippocampus ‘is a small, seahorse-shaped structure that store your conscious memories in an organized way,’ (Greenberg 2016).


The result? Over protracted periods this neurological damage can result in a weakening of neural networks leading to diminished memory recall and, in the most severe cases, early onset of cognitive decline. The brain that weathers a lot of stress wears quicker.


Few people realize that silent killer is linked to a wide range of physical illnesses some of which include:

  • Headaches

  • Infectious illness (such as influenza)

  • Cardiovascular disease

  • Diabetes

  • Asthma

  • Rheumatoid arthritis

  • Mood swings

  • Suicide ideation

(List adapted from Curtis 2000)

Two types of stress

Before we go any further, it is important to point out that not all stress is bad for us. In fact, short-duration stress, the stuff that gets us motivated or compels us to take action, can actually be beneficial.


However, long-duration stress can erode our health and increase our risk of succumbing to the diseases and conditions highlighted above.


But the difficulty lies in distinguishing the two types, knowing which is short-duration and which is chronic.


Below, the two types have been briefly outlined and explained. Familiarise yourself with the distinctions so that, during times when you feel stressed, you can run a diagnostic and determine which type it is.

Type 1: Acute or short-term stress

In a moment of absentmindedness, you step into the road without looking, a car whizzes past while honking furiously. As well as sending your heart rate through the roof this causes a cascade of other physiological responses: an adrenaline dump, heightened arousal, perhaps a sick feeling in the stomach, sweating.


But after giving yourself a good and much deserved dressing down you go about your merry way like nothing happened. After all, the crisis is now over so why dwell on it?


  • It is short-lived and the associated responses dissipate after a few minutes

  • It triggers an intense spike of physiological responses

  • Type 1 can be induced by a million and one things

Type 2: Chronic or long-term stress

For months and months your boss has been saddling you with more and more work responsibilities and you’re feeling overwhelmed and you’ve got knots in your stomach and you can’t sleep and you’re constantly anxious and worried and, and . . .


Yep, this is chronic stress and it’s the stuff that’ll make you ill and, if not treated, potentially prematurely divest you of your mortal coil.


  • It’s long-lived and can linger in the mind and body for days, weeks, months or even years.

  • Comparative to Type 1, Type 2 is somewhat ‘mild’ in intensity. And though this may seem like a positive it isn’t. Because of this characteristic, it can lurk undetected which is where it begins sabotaging your health.

  • It is triggered by a whole host of things but typically chronic stress is caused by: work (otherwise known as ‘occupation stressors’ which the WHO says ‘is the response people may have when presented with work demands and pressures that are not matched to their knowledge and abilities and which challenge their ability to cope’²), toxic relationships, money (the lack of it) and poor socioeconomic circumstances (for example, being poor, having to endure a demeaning job and living in a crappy neighbourhood).