When activated, the fight or flight system leads to a series of physical changes in the body. Relevant to irritable bowel syndrome, the fight or flight response causes decreased activity in the digestive system. This is to allow more energy to go to organs and muscle groups that are essential for survival. When you’re faced by a saber tooth tiger, digesting your breakfast becomes less important. As such, blood is directed away from the stomach and the bowels either empty quickly or tense up.
Stress-related changes in the stomach and colon can lead to irritable bowel syndrome-like symptoms, including dry mouth, stomach pain, nausea, constipation, or diarrhea. Stress can also increase pain sensitivity, making irritable bowel syndrome symptoms more painful during times of stress. As discussed above, the fight or flight response is intended to be short lived. However, many of today’s stressful situations cannot be dealt with quickly. Chronic activation of the stress response often results in more severe irritable bowel syndrome symptoms. For example, one study found that irritable bowel syndrome patients with ongoing stress had poorer outcomes than those with less stress.
When the fight or flight system is activated, the brain sends signals to the body to release stress hormones (i.e., ‘cortisol’ and ‘adrenaline’). In controlled amounts, these hormones prepare us for action. However, too much cortisol and adrenaline is bad for the body. For example, it can cause digestive, inflammation and immune system problems. These effects can lead to a range of disorders, including irritable bowel syndrome. Researchers have shown higher cortisol activity in people with irritable bowel syndrome compared to people without this condition.
The relationship between stress and irritable bowel syndrome appears to go both ways. Stress is a major issue for many people with irritable bowel syndrome. Constant fear of leaving the house or finding a bathroom in time can result in chronic activation of the stress response. The impact of irritable bowel syndrome symptoms can also be debilitating and stressful in their own right. People with irritable bowel syndrome are also more likely to have a history of trauma, which sensitises them to everyday stress. This means that their fight or flight system is more likely to react to even minor stressors.
As you can see, stress and irritable bowel syndrome interact with and worsen each other. This can create a vicious cycle that’s hard to break out of. Before moving on, have a think about stress in your life. What aspects of life make you feel stressed? Are these short-term worries or ongoing problems? Does stress seem to impact your irritable bowel syndrome symptoms, or vice versa?