The gut has it’s own nervous system (Enteric Nervous System), which largely regulates the motility, secretions and functions within the gut. The Central Nervous System, however, monitors and can influence these functions depending on cognitive factors, pain perception or emotional influences. These can affect gut motility, secretions and sensations. Primarily, the Enteric Nervous System controls the gut independently, keeping the CNS informed. The CNS only overrides the ENS in important situations.

The brain and the gut are in constant communication with each other, allowing information associated with the functioning of the gut to pass to the Central Nervous System, primarily along the Vagus nerve.

As previously mentioned, stress can affect our gut in the short term and long term. In response to stress, threat or strong emotions (or as part of our body’s “fight or flight” survival mechanism) our brain (CNS) prioritises survival over digestion and can override the ENS. The release of stress hormones, allows upper GI function to slow down, (minimising digestive processes) and lower GI motor function is stimulated, potentially increasing gut motility and contributing to diarrhoea.

Adrenaline is released, increasing the heart rate and boosting the body’s energy levels. Cortisol is released increasing sugar supplies in the blood stream. The stress response is designed to be a short-term response, however, if activated in the long term, may have a more chronic, disruptive effect, on the normal functioning of the gastrointestinal system.

Therefore, it is important for some people, to minimise the internalisation of strong emotions, as this can disrupt and interfere with the normal functioning and rhythm of the gut.