Skip to contentSkip to navigation

Specialist Advice — 15 minutes

How stress influences your gastrointestinal health

Raymond Lepage, PhD, Doctor in Biochemistry
Raymond Lepage, PhD, Doctor in Biochemistry
Science popularizer

Stress has often been described as a scourge of the modern world. Although human beings have always been exposed to it, it wasn’t until the middle of the last century that Dr. Hans Selye of Université de Montréal was able to understand the physiological mechanisms at work.[1] It’s now known that stress affects every organ and function in the body: the brain, immune system, heart, muscles, bones and digestive system, particularly the intestines.

Read more: Can a person’s exposure to stress be measured?

The stress response

Stressful events aren’t the same for everyone. While almost all people are alarmed by very loud noises or aggressive situations, only some are chronically stressed by more mundane events in everyday life. In all cases, the brain triggers a dual hormonal response involving catecholamines on the one hand and cortisol on the other.


Catecholamines, such as epinephrine (adrenaline) and norepinephrine (noradrenaline), act as first responders to situations that are interpreted as a threat by the brain. We’ve all experienced some of the side effects of this response when we’re startled, narrowly avoid an accident or experience a panic attack: sweating, increased heart rate, breathing and blood pressure, red cheeks, trembling, etc. These unpleasant effects conceal a whole series of important physiological mechanisms that occur simultaneously and serve to fight or flee the danger. The catecholamine response is rapid but short-lived. It becomes harmful if it’s repeated too often.


At the same time as it stimulates the production of catecholamines, the brain instructs the pituitary gland to stimulate the secretion of cortisol by the adrenal glands. Together with catecholamines, cortisol releases glucose into the bloodstream to meet energy needs from glycogen, fat and even protein reserves. It inhibits energy-intensive functions such as growth, digestion and reproduction. The effects of cortisol aren’t as noticeable as those of catecholamines. However, they last longer and become harmful if stressful episodes are chronically repeated.

Read more: When should you worry about abdominal pain?

Stress and gastrointestinal health

Of course, the digestive system can’t escape the combined effects of catecholamines and cortisol. Who hasn’t felt discomfort such as a knotted stomach, bloating, nausea, or the urge to have a bowel movement or urinate before or during a particularly stressful event? These phenomena occur when the brain directs all of its attention to the fight or flight response. This response involves a part of the nervous system called the “sympathetic nervous system.”

The price paid for this mobilization of the sympathetic nervous system is the decreased activity of another nerve network, the parasympathetic nervous system. This system, through the vagus nerve, normally relaxes the muscles and increases bowel movements. At the same time that bowel movements are slowed by the reduced activity of the vagus nerve, the nerve that controls the bladder and rectum remains active, resulting in the urge to urinate or defecate when experiencing stress.

Over the long term, chronic stress can lead to many gastrointestinal complications by aggravating existing conditions such as the following [2]:

  • Inflammatory bowel diseases (IBD)
  • Irritable bowel syndrome (IBS)
  • Gastroesophageal reflux disease (GERD)
  • Peptic ulcers

Inflammatory bowel diseases

Several studies demonstrate that chronic stress can increase the risk of relapse in patients with Crohn’s disease or ulcerative colitis. The mechanisms are complex, but certainly include the ability of stress hormones to decrease the immune response and increase the inflammatory response.[3]

Irritable bowel syndrome

Although we don’t know all the mechanisms at work, irritable bowel syndrome has a major psychological component. There is constant, two-way communication between the brain and intestines, which is sometimes considered our “second brain.” This communication involves mediators of nerve transmission, hormones secreted by the digestive tract which act on the brain, and many molecules produced by the microbiome (the collection of bacteria that colonize the intestine).[4]

Gastroesophageal reflux disease (GERD)

Studies on a large number of subjects have shown that the level of stress and anxiety is significantly higher in people suffering from gastroesophageal reflux disease than in others.[5]

Peptic ulcers

The vast majority of stomach and peptic ulcers are caused by an infection with the Helicobacter pylori bacterium. H. pylori acts by attacking the mucous membrane that protects the stomach lining from the acids produced during digestion. It’s been observed that regardless of whether subjects had an H. pylori infection or were taking non-steroidal anti-inflammatory drugs, the incidence of peptic ulcers is higher in people suffering from psychological stress than those in the control group.[6]

To learn more about these conditions, consult our neat little guide to digestive disorders.

How to protect the intestines from the effects of stress

To protect the intestines from the effects of stress, we must first protect ourselves from stress. There are dozens of ways to do this, and everyone should try to find the one that works for them. Here are a few examples adapted from the Health Canada website [7]:

  • Try to create a work-life balance.
  • Take the time to laugh and have fun.
  • Learn to delegate. Don’t try to do everything yourself.
  • Try yoga, meditation or visualizing happy events.
  • Take regular walks or listen to music.
  • Get some exercise.
  • Learn how to manage your time (establish priority lists).
  • Eat a healthy diet (beware of alcohol and overly rich meals).
  • Get some rest and the sleep your body needs.
  • Talk about your problems with your loved ones or a counsellor.
  • Take a vacation once in a while.
  • Learn to not always have the last word. Be less competitive.
  • Don’t try to be perfect.

For people who suffer from anxiety, medications such as anxiolytics and some antidepressants may be helpful.[8]

For professional support, we’re here.

We provide services that can help your doctor diagnose stress-related disorders and determine whether a medication may be ineffective or cause adverse effects. Please note that these tests are not used to measure stress levels, and that this is a non-exhaustive list.

Do you have a doctor's prescription on hand for one of these tests? Book an appointment online or contact Biron Health Group’s customer service at 1 833 590-2712.

  1. Selye H., Le stress de la vie, Paris, Gallimard, 1962
  2. Canadian Society of Intestinal Research, “Stress and Your Gut.” Consulted October 8, 2020.
  3. Mawdsley J.E. and D.S. Rampton, “Psychological stress in IBD: New insights into pathogenic and therapeutic implications,” Gut, 2005, 54, p. 1481-1491
  4. Goucerol, G., “Stress et syndrome de l’intestin irritable.” Consulted October 8, 2020.
  5. Choi J.M., J.I. Yang, S. J. Kang et al., “Association Between Anxiety and Depression and Gastroesophageal Reflux Disease: Results From a Large Cross-sectional Study,” J Neurogastroenterol Motil, Oct. 2018, 24(4), p. 593-602
  6. Deding U., L. Ejlskov, M.P.K. Grabas et al., “Perceived stress as a risk factor for peptic ulcers: a register-based cohort study,” BMC Gastroenterol, 2016; 16, p. 140. Published online on November 28, 2016. Consulted October 8, 2020.
  7. Health Canada, “How Can I Deal most Effectively with Stress?” Consulted October 8, 2020.
  8. Mayo Clinic, “Anxiety disorders.” Consulted October 8, 2020.
Dr Nicolas Tétreault, Clinical Biochemist, Ph.D., FCACB, CSPQ
Dr Nicolas Tétreault, Clinical Biochemist, Ph.D., FCACB, CSPQ
Scientific and Innovation Director
Having practiced in the public and private networks while constantly monitoring the evolution of biomedical laboratory medicine, Dr. Tétreault, a clinical biochemist, stands out for his innovative vision and unique expertise in the Canadian, American and European markets. He teaches at the Université de Montréal and regularly publishes texts intended for the general public or experts in the field.