How Chronic Stress Can Kill You

17 June 2018 by Madeline Shepherd

How Chronic Stress Can Kill You

We live in a world full of stress—busy jobs, tight finances, relationships.

But our bodies can’t tell the difference between chronic stress, and a life-threatening situation. In this article, I will teach you about the very important parasympathetic vs sympathetic states and how these stress responses affect every cell in your body.

You will want to address your chronic stress issues by the end!

A beginners guide to the severe impacts of stress on your physiology.

Animals have two very opposite states that enable survival:

  • Rest and digest – parasympathetic state
  • Fight or flight – sympathetic state

Being able to utilise both states is critical for survival. When we lived as animals in the wild (yes, we ALL evolved as hunter-gatherers), we needed to be able to switch on our survival mechanisms to escape predators and hunt for food.

As soon as that acute stress passed, the need for fight or flight disappeared and we returned to a relaxed state. Being in a relaxed state is just as important as fight or flight, because of the critical processes that happen when we are relaxed.

The autonomic nervous system 

Whether our body is in a parasympathetic (rest and digest) or sympathetic (fight or flight) state depends on the feedback to our brains. If we see or perceive danger, our brain tells us to activate fight or flight.

These two states are regulated by our body’s autonomic nervous system and this is controlled by our vagus nerve (sometimes referred to as vagal nerve). The vagus nerve stems from the base of the skull and runs all the way down the body, controlling a huge number of functions along the way.

Digestive function, for example, is regulated by the vagus nerve, because it is such an energy-intensive process. If we perceive stress, then our energy certainly shouldn’t be wasted on helping us digest our food. All energy needs to go towards getting us away from the danger!! 

Parasympathetic state: Rest and digest

Your parasympathetic state is your body’s relaxed mode. We should be in a parasympathetic state most of the time, because being relaxed is key to maintaining homeostasis (balance in the body).

There are a number of very important bodily functions that take place when our body is in parasympathetic state. Let’s have a look at them:


If we are not relaxed when we eat, our digestive system shuts off and food doesn’t get broken down or absorbed properly. This can result in leaky gut, nutrient deficiencies and more. Being in parasympathetic state enables the following digestive processes:

  • Adequate production of hydrochloric acid in your stomach to break down food, especially proteins;
  • Secretion of the necessary enzymes to break down all food molecules
  • Stimulation of bile production and release from the liver and gallbladder to emulsify (breakdown) fats;
  • Peristalsis (muscle contractions that push food through the GI tract);
  • Forms healthy and solid stools that help eliminate toxins from the body.
  • When these processes aren’t working, as a result of being stressed or not properly in the parasympathetic state of “rest and digest” then we can end up with issues downstream.

If your food doesn’t get adequately broken down upstream, then what will it be like when it reaches your gut? The answer: still in large pieces that will damage the sensitive lining of your GI tract and cause leaky gut.

I have covered why leaky gut is a huge problem in these articles on leaky gut and about the strong links between leaky gut and autoimmunity.


Identifying, preparing and eliminating waste only takes place when we are in a relaxed state. If we don’t detoxify then the toxic load from our modern lives (food, makeup, pollution etc) accumulates with severe health consequences. I have written about detoxification in these articles here and here.

In today’s industrialised, polluted and stressful world our bodies are exposed to a huge toxic load that we really weren’t made for. Most of our evolution to the human beings that we are today occurred thousands of years ago, well before machines, chemicals, industrial farming, pesticides and more. So our bodies are NOT well equipped to deal with the heavy toxic burdens. The process of detoxification is more important today than ever before. For our body to be detoxing it needs to be in a parasympathetic state.

Immune function

Our body is only interested in our long-term health if our short-term survival is guaranteed.

Not being in parasympathetic state can severely impact our immunity with very serious consequences such as cancer.

Sympathetic state: Fight or flight

You’ve probably heard of the terms “fight or flight.” This is the colloquial label we give to the stressed state in the human body. Historically this mechanism was used to escape a predator so it was vitally important. The fight or flight response triggers our stress hormones, cortisol and adrenaline (or epinephrine).

These hormones, in turn, prompt various survival mechanisms so we can move fast:

  • Increases heart rate
  • Dilation of blood vessels
  • Release of stored glucose from our muscles and liver
  • Release of proteins from the musculoskeletal system that is turned into glucose.

All of these physiological responses were intended to help us escape predators. They served essential purposes thousands of years ago when we were hunter-gatherers and were faced with life and death situations on a regular basis. A faster heart rate and dilated blood vessels allow the blood to be pumped quickly around the body meaning we could quickly escape from the beast chasing us, or that we could chase an animal that we were seeking for food. 

Fight or flight mode served an important evolutionary function. The problem is that in the modern world we experience frequent stress and our body reacts the same as it used to. Stress is an ever-present factor in our lives, even if we don’t always realise it.

Consider the following situations:

  • Being stuck in traffic
  • Fighting with a loved one
  • Being late to a meeting

Our brains don’t really delineate between different types of severity of stressors. So anything our brain perceives to be stressful can cause the physiological responses outlined above.

As the result of our stressful lives, many people are constantly in a sympathetic state. 

We should be spending more time in parasympathetic mode to achieve both physical and mental health.

When we are in one state, we aren’t in the other. If we are constantly in a stressed state then the very important functions outlined above can stop working. If we aren’t digesting food properly the problems are two fold – we don’t absorb nutrients AND we overload our system with maldigested food particles. With impaired detox and immune capacity, this is not a good situation to be in and the health consequences are severe.

This is how chronic stress can become life-threatening.

Chill out – Getting into a parasympathetic state 

There are some simple things that you can do to help bring your body into a parasympathetic state. This is particularly important before you eat, because of the link between digestion and parasympathetic state.

  • Deep breathing – exhale for slightly longer than you inhale
  • Meditation
  • Stroking the dint just behind your ears (ie the vagus nerve)
  • Going for a walk
  • Yoga
  • Light exercise (not a huge workout which acts as a stressor)
  • Laughing
  • Spending time with loved ones
  • Sipping peppermint, ginger or chamomile tea

Managing stress is more important than we realise. The consequences of failing to do to so can lead to a host of severe health consequences.

If you are struggling with stress and its impacts on your health, you could benefit from working with a functional nutritional therapist. Get in touch with me today at

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Madeline Shepherd

Maddy runs the popular blog "A No Grainer", which dispels some of the myths around 'healthy eating' and is a certified FNTP. Find her at