You already know that managing stress and resting are important for your mental and physical health, but did you know that there is a direct link between digestion and your stress response? You may have heard the terms fight or flight and rest and digest – but what do these mean, and how does stress really impact your gut health? Read on to find out!
What is the Autonomic Nervous System (ANS)?
To get an idea of how this works, we need to look at the Autonomic Nervous System (ANS) and what it does. The ANS regulates involuntary physiological processes1https://my.clevelandclinic.org/health/body/23273-autonomic-nervous-system2https://www.ncbi.nlm.nih.gov/books/NBK539845/ such as:
- Blood pressure
- Respiration
- Digestion
- Sweating
- Insulin and hormone regulation
- Bladder control
- Sexual arousal
The ANS is made up of a network of nerves around the body, extending from the brain3https://my.clevelandclinic.org/health/body/23273-autonomic-nervous-system and spinal cord. It contains the following components: the parasympathetic, the sympathetic and enteric nervous systems.4https://www.sciencedirect.com/science/article/abs/pii/B9780444640321000278?via%3Dihub
What do the parasympathetic, sympathetic and enteric nervous systems do?
The parasympathetic nervous system is known as ‘rest and digest’5https://my.clevelandclinic.org/health/body/23266-parasympathetic-nervous-system-psns, while the sympathetic nervous system is known as ‘fight or flight’ – these systems have complementary roles, you need both!6https://my.clevelandclinic.org/health/body/23266-parasympathetic-nervous-system-psns
Sympathetic Nervous System
Your sympathetic nervous system gets you ready to fight or flee physiologically when your body senses a stressor. In hunter-gatherer societies this was activated in situations such as being chased by animals, evading predators or fighting rivals. In the modern day these stressors look quite different like school, work, relationship and financial stress.7https://now.tufts.edu/2013/02/12/programmed-fight-or-flee
When your sympathetic nervous system is activated, your digestion slows, your heart rate increases, adrenaline is released, energy stores in the liver are activated for quick energy use and your pupils become enlarged to let more light in. These responses prepare you to act quickly and to face the stressor – whatever that may be.8https://my.clevelandclinic.org/health/body/23262-sympathetic-nervous-system-sns-fight-or-flight
Parasympathetic Nervous System
Your parasympathetic nervous system helps you relax and is activated during times of rest. It lowers your heart rate, stimulates saliva response to aid breathing and digestion, relaxes the muscles that control urination and defecation. It also increases your digestion rate, drawing energy to help digest food as well as supporting the production and release of insulin to help control blood sugar.9https://my.clevelandclinic.org/health/body/23266-parasympathetic-nervous-system-psns
Enteric Nervous System
The enteric nervous system is a recent addition to our understanding10https://pubmed.ncbi.nlm.nih.gov/31277865/ of the ANS. It is a separate nervous system for the bowel, regulating bowel motility in digestion11https://www.ncbi.nlm.nih.gov/books/NBK279390/ and the gut immune response.12https://pmc.ncbi.nlm.nih.gov/articles/PMC5551410/
It is made up of a system of approximately 50 million neurons and is sometimes referred to as the ‘second brain’.13https://www.mayoclinic.org/healthy-lifestyle/stress-management/in-depth/stress/art-20046037 Alongside the central nervous system, the enteric nervous system forms the gut-brain axis, a bidirectional communication pathway linking the brain with peripheral intestinal functions.14https://pmc.ncbi.nlm.nih.gov/articles/PMC4367209/
Why are these systems important for gut health?
You may be thinking, but I can’t avoid all stress, and you’re right! Some stress is unavoidable but you may be surprised to find out that not all stress is bad! Some stressors can be enjoyable, inspiring and motivating. Your stress response can also aid you in tricky situations.15https://www.ncbi.nlm.nih.gov/books/NBK541120/ For example, if you were being attacked, you would want your physiological response to kick in, helping you to fight or run away.
However, being under prolonged or chronic stress can lead to cumulative physiological and psychological effects – increasing the risk of health problems such as anxiety, depression or cardiovascular disease.16https://www.ncbi.nlm.nih.gov/books/NBK541120/ Watch out, as this stress may not always be visible!
Prolonged sympathetic activation (chronic stress) adversely affects your gut. The hormones epinephrine (adrenaline) and norepinephrine (noradrenaline), released during stress, profoundly affect the gastrointestinal system. They bind to androgenic receptors in the gut which can cause slow motility and delayed gastric emptying. These receptors can also reduce blood flow to the gut inhibiting your ability to absorb nutrients. This stress can impair the integrity of your gastrointestinal mucosal barrier – leading to increased permeability and susceptibility to infection and inflammation.17https://www.ncbi.nlm.nih.gov/books/NBK541120/
The adverse effects listed above can contribute to imbalances in the gut – this is gut dysbiosis. We talk a lot about gut dysbiosis here at CG as it’s important to address if you want to improve your gut health! We created our Microbiome Test so you can get the data driven lowdown and figure out what you need to fix with guidance not guesswork.
We will all face stressors that activate our sympathetic response. However, we want to be able to activate our parasympathetic response so that we can rest mentally and physiologically. Improving your stress response is just another way to improve your gut health!
For more on this, check out How is your mental wellness connected to your gut?.
Any questions? Contact one of our Nutritional Therapists via live chat, weekdays from 8am to 8pm.
References
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
- 11
- 12
- 13
- 14
- 15
- 16
- 17
