Fitness & Healthy Lifestyle

Stress & The Digestive System

Have you ever had a busy day & felt twinges or pain in your stomach, or just found you are uncomfortably bloated by the afternoon? Although there are many reasons for digestive discomfort, stress is a key factor & it affects most of us at some point in our lives.

Stress can negatively impact the gut in a few ways. Some of the most common digestive symptoms related to stress include:

  • Bloating
  • Nausea
  • Indigestion
  • Pain &/or discomfort
  • Heartburn & Acid Reflux
  • Feeling full & uncomfortable for long periods
  • Slow digestive transit
  • Diarrhea & constipation in flux

Learning a little more about the effect stress has on our nervous system is key here, but firstly let us go through the carefully considered process that is our digestion; like a ladder, it is a step by step process, & each step relies on the one before to do its job well.


It all begins with salivary amylase (an enzyme) in the mouth, which starts the breakdown of carbohydrates. The mechanical digestion from chewing + this chemical dissolution then means we can swallow our food whilst also telling the stomach to release gastric acid + more digestive enzymes.

The gastric juice (AKA stomach acid) creates the optimum pH (acidic environment) for protein & fat digestion & triggers the pancreas to secrete its enzyme contribution.

When we talk about stomach acid many won’t realise that its strength is pretty much equitable to that of the acid you find in a battery, far too corrosive to come into contact with the tissues outside of the particular environment it is designed to be contained within. This should be kept in check by 2 tight muscular rings though, 1 at the top of the stomach & 1 at its base (the oesophageal & pyloric sphincters respectively).

When food enters the stomach these should tightly seal, that washing machine of battery acid turns on & once the optimum pH is reached that delightful mush should then move into the small intestine because the pyloric sphincter will be triggered to open at the opportune moment based on that acid level. There the chyme (partially digested food) will meet those pancreatic enzymes that are waiting for it. Bile is also here having been released by the gallbladder to emulsify fat droplets, & something called intrinsic factor is also present which is integral for B12 absorption. We don’t really see that food as food anymore, & the broken-down nutrients are absorbed & assimilated into our body. The intestines are then triggered to create a wave-like movement called peristalsis which moves everything along the metres of intestinal lining until eventual excretion.


The nervous system has branches related to up-regulating or down-regulating specific pathways concerning stress or relaxation. These branches are called the sympathetic & parasympathetic nervous systems.

When we face a stressor, our sympathetic nervous system comes into play; this is responsible for preparing our body to survive this hurdle.

In evolutionary terms this would be physical danger such as an animal attack or environmental event (flood, drought, storm) which is where the term fight or flight response originates. Adrenaline & cortisol (our stress hormones) are spiked, our breathing becomes rapid, heart rate/blood pressure increases, blood is sent to our brain, arms & legs, you know the drill!

Processes within the body that are non-essential for survival are consequently down-regulated because we don’t need to reproduce, digest or consider longer term immunity if we don’t survive the current crisis. These all shift into a more dormant state in favour of allowing all resources to be sent elsewhere.

In an evolutionary sense, this was an incredibly effective mechanism for running as fast as you could from a lion without the pesky issue of having to worry about sending too much energy to your stomach to digest the meal you just had.

However these days we aren’t so concerned about lions but somewhat more focused on that presentation at work, marshalling kids to school whilst also balancing other responsibilities, dealing with a traffic jam when we’re already tight for time…..basically our fight or flight response is triggered by many non-physical dangers.

It is also important to highlight that non-emotional triggers will also contribute to sympathetic nervous system dominance including cardiovascular exercise & lack of sleep. Which is very often not equally matched by appropriate downtime where our parasympathetic (rest & digest state) becomes dominant & those hugely important mechanisms that have been slowed down become active once more.

If we link this back to that delicate chain reaction we started with what we see digestively in sympathetic nervous dominance is:

  • A reduction in all digestive secretions.
  • Lower levels of stomach acid.
  • Inhibitions of pancreatic enzyme release.
  • Churning of the stomach to digest food but without the appropriate level of the above causing an increased likelihood of nausea & burping. Occasionally shortness of breath & back pain may accompany this.
  • An overflow of stomach acid through the oesophageal sphincter, creating acid reflux.
  • Increased pressure on the lower digestive tract due to undigested food moving into the small intestine. This will cause bloating, flatulence & discomfort.
  • A misfiring or lack of communication between the stages leading to intermittent bowel movements.

Over time the intensity of this burden will increase creating more intense symptoms whilst also decreasing the absorption of nutrients from our food.

This can then lead to poor eating habits due to low energy, disturbed sleep & imbalances in bacterial, fungi & yeast colonies within the intestines.

For those suffering with heartburn or acid reflux related to stress it seems sensible to try & dial back the acidity in the stomach, but paradoxically this just worsens the situation by further reducing the chemical breakdown of food in the stomach.

Low stomach acid will also prevent the pyloric sphincter from opening keeping food in the stomach for longer, this upward pressure then often being the mediating element for that burning sensation after eating. It can be a real catch 22, but getting to the root cause is hugely important & sometimes that can be as simple as reducing stress & over activation of the sympathetic nervous system.

As noted above, stressed eating can also contribute to bacterial overgrowth in the small intestine (SIBO), as food is left undigested for longer & ferments. Conversely to large intestine bacterial imbalance, SIBO is often more systemically symptomatic in nature, creating headaches, nausea, issues with pain & more. Brain fog & cognitive concerns are often linked here too.

Being more mindful in our eating habits can be hugely helpful in starting to reverse these issues, find our top tips to do this below:

Firstly breathe. Breath is the most powerful tool we have when it comes to controlling our nervous system. The rate and depth of breath can shift us into either a sympathetic or parasympathetic response.

  • Before a meal, make time to take some deep breaths, wherever you are! Inhale slowly for the count of 4-5, & exhale slowly for 8-10. If it’s comfortable, hold at the top of your breath for 4 counts, you can alter the numbers to fit your breathing comfortably, but the key aspect is exhaling for longer than the inhale. 8 rounds of this breathing will effectively calm the nervous system & prepare your body for mindful eating & optimum digestion.

We start to release salivary amylase even before we take our first bite. This is in anticipation of eating & it starts off the whole chain of events. So again, taking a moment to anticipate the enjoyment you will gain from it can help the digestive juices flow.

  • Take an extra few minutes to smell what you’re making, & plate your food attractively! The old adage ‘we eat with our eyes’ is actually based in a physiological mechanism!

With the same mindful approach, chewing food slowly creates a more straightforward job for digestion, making the whole process much more effective. Sometimes we can blame our gut for the discomfort, but it can be alleviated simply by chewing food slowly & savouring it a little longer.

  • We love something crunchy & bitter to begin our meals, that neurological feedback also acts as an alarm for the layers coming next.

On the unavoidably busy days, just help your body out a little with your food choices, avoid raw vegetables as these are already harder to digest. Warm soups & stews are an excellent easy-to-digest option & paired with your choice of protein, make a perfect speedy yet nutritious lunch.

Eat gut loving foods! Increase gentle fibres from veggies including squash, sweet potato, artichokes & peas, or add butter beans or chickpeas to stews. Some probiotic foods such as kefir, sauerkraut, coconut yogurt & kimchi are wonderful to eat to establish a healthy & diverse gut microbiome!

  • We are big fans of the Eaten Alive products. Use NATNOURISH10 for 10% off everything in their range.

Caffeine will spike cortisol & act as a stressor to the body; it is wise to reduce caffeine in times of stress. If you love coffee, perhaps try switching to matcha, which is a little gentler & contains L-Theanine (an amino acid that has a calming effect on the brain). Raw cacao is another fabulous choice here too.

  • Chamomile, fennel & dandelion herbal teas make a great choice for easing digestion & are naturally caffeine free.

During stressful times adapt your exercise too. Physical activity comes in many forms so try swapping a few HIIT classes or runs (if you run!) for walking or more gentle forms of movement, again to try & lower that sympathetic over activation.

  • Yoga & meditation are beautiful tools to encourage full mindful breaths, & as well as forming part of your daily exercise routine can increase digestive efficacy by toning the diaphragm (the muscle that separates upper & lower body). Many people breathe shallow short breaths without realising which perpetuates that internal stress response & also doesn’t help with that calm peristaltic wave.
  • If you are really suffering we also suggest perhaps keeping a track of your digestive symptoms along with what and how you’re eating, to see if you can identify any patterns. Getting to know your gut and learning how to manage stress can make a hugely positive impact to your overall health & wellbeing. And of course we are always here to help if you need us to!

Written by Rose Dalrymple

Associate Nutritional Therapist & Yoga Teacher