Understanding pain, urgency, and sensitivity.
Written by Dr. Antonia Repollet
Licensed Clinical Psychologist
Certified School Psychologist
GI Psychology
If you have irritable bowel syndrome (IBS), you already know that IBS does not show up the same way every day. Some days are manageable. Others are defined by pain that won’t quit, a sense of urgency that dictates where you can and cannot go, or a gut that seems to react to everything. These periods of intensified symptoms are commonly called flare-ups, and understanding what is actually happening in your body during one can make them feel a little less mysterious and a lot less like a personal failing.
What Is an IBS Flare-Up?
IBS is a disorder of gut-brain interaction (DGBI), meaning it arises not from structural damage or disease detectable on imaging or lab work, but from dysregulation in how the gut and brain communicate (Drossman, 2016). The gut is lined with its own nervous system — the enteric nervous system, sometimes called the “second brain” — and it is in constant, bidirectional communication with the central nervous system. When that communication becomes dysregulated, the gut can behave in ways that are unpredictable, painful, and disruptive.
A flare-up is a period when that dysregulation becomes more pronounced. Symptoms that may have been mild or manageable intensify. They may last hours, days, or longer, and they can look different from one person to the next, or even from one flare-up to the next in the same person.
The Main Symptoms of a Flare-Up
Pain and cramping
Abdominal pain is the hallmark of IBS, and during a flare, it often becomes more frequent, more severe, or more difficult to relieve. The pain most commonly occurs in the lower abdomen but can appear anywhere, and it may be crampy, sharp, aching, or pressure-like. For many people, the pain temporarily worsens just before a bowel movement and improves somewhat afterward, though this relief is not always complete or lasting (Ford et al., 2014).
The reason IBS pain can feel so disproportionate to what is actually happening in the gut comes down to a phenomenon called visceral hypersensitivity. People with IBS have a lower pain threshold for normal gut sensations meaning sensations like gas, stool moving through the colon, or mild intestinal contractions that a person without IBS might not notice at all (Mayer & Tillisch, 2011). During a flare, this heightened sensitivity becomes more pronounced, which is why ordinary digestive activity can feel genuinely intolerable.
Urgency and altered bowel habits
Urgency or the sudden, often overwhelming need to use the bathroom without much warning, is one of the most distressing symptoms of a flare, and one of the most disruptive to daily life. For people with IBS-D (diarrhea-predominant) or IBS-M (mixed), flares often bring loose, frequent stools, urgency, and in some cases, incomplete emptying or the sensation that more remains even after a bowel movement.
For those with IBS-C (constipation-predominant), flares may bring increased difficulty passing stool, straining, and the passage of hard, pellet-like stools, sometimes alternating with episodes of loose stool. Bloating and a feeling of abdominal fullness or distension often accompany both patterns.
Bloating and gas
Bloating is nearly universal in IBS, and during a flare, it is frequently one of the most uncomfortable and visible symptoms. It may worsen throughout the day, feel better in the morning after a night of rest, or persist without relief. Research suggests that bloating in IBS is not always a matter of excess gas production. It is often a result of how the gut handles gas and how sensitive the gut wall is to normal amounts of it (Lacy et al., 2016). This is another expression of visceral hypersensitivity.
Nausea and fatigue
Less often discussed but very common, nausea frequently accompanies IBS flare-ups, particularly in those whose symptoms are more severe overall. Fatigue is also commonly reported, not just as a consequence of poor sleep during a flare, but as a symptom in its own right. The gut-brain connection means that when the gut is in distress, the nervous system as a whole is often dysregulated, and that dysregulation takes an energy toll (Ballou & Keefer, 2017).
What Triggers a Flare-Up?
Flare-ups rarely come from nowhere, even when they feel that way. Common triggers include:
Stress and emotional activation. The gut-brain axis is exquisitely sensitive to psychological stress. Research consistently shows that stress, anxiety, and even anticipatory worry about symptoms can directly alter gut motility, increase intestinal permeability, and amplify pain signals (Mayer, 2011). This is not a matter of “it’s all in your head”, it reflects a genuinely bidirectional biological relationship.
Dietary factors. Certain foods are well-established triggers for many people with IBS: high-FODMAP foods (fermentable carbohydrates that are incompletely absorbed and rapidly fermented in the colon), fatty or fried foods, caffeine, alcohol, and large meal volumes. That said, dietary triggers are highly individual. What provokes a flare in one person may be completely tolerated by another.
Hormonal changes. Many people with IBS, particularly women and those assigned female at birth, report that symptoms worsen predictably around menstruation. The gut has receptors for estrogen and progesterone, and hormonal fluctuations across the menstrual cycle appear to influence gut motility and pain sensitivity (Heitkemper & Chang, 2009).
Sleep disruption. Poor sleep and IBS have a bidirectional relationship. Disrupted sleep impairs the gut’s ability to regulate itself and increases sensitivity to pain, while a gut flare-up makes restorative sleep far more difficult to achieve.
Illness or antibiotic use. A gastrointestinal illness or a course of antibiotics can disrupt the gut microbiome in ways that trigger or prolong a flare for some people.
Why Flares Can Feel Unpredictable
One of the most frustrating aspects of IBS is that even when you are doing everything “right” (i.e. eating carefully, managing stress, getting enough sleep), a flare can still happen. This is not a failure of effort or willpower. It reflects the complexity of the gut-brain axis, which is influenced by factors that are not always fully visible or controllable: changes in the nervous system’s baseline reactivity, shifts in the microbiome, immune system activity, and more.
For many people with IBS, the unpredictability of flares is itself a significant source of distress, which can in turn amplify the gut’s sensitivity — a cycle that is both real and understandable. Naming this cycle is not about blaming the brain for physical symptoms. It is about recognizing that the gut and brain are one interconnected system, and that caring for both matters.
What Can Help During a Flare
Evidence-based approaches for managing IBS flare-ups include both medical and behavioral strategies:
- Gut-directed hypnotherapy has some of the strongest evidence of any treatment for IBS, with studies showing significant and lasting reductions in pain, urgency, and overall symptom burden across multiple randomized controlled trials (Moser et al., 2013). It works, in part, by modulating the brain’s processing of gut signals — directly targeting visceral hypersensitivity at its source.
- Cognitive behavioral therapy (CBT) adapted for GI conditions helps people develop more flexible responses to symptoms and reduce the anxiety-symptom cycle that can perpetuate flares over time.
- Acceptance and Commitment Therapy (ACT) can be particularly helpful for the distress and life interference that accompany IBS, supporting people in living more fully even when symptoms are present.
- Dietary approaches can help identify individual food triggers, though these are best done with appropriate support.
- Medical management, coordinated with a gastroenterologist familiar with DGBIs, may include symptom-targeted medications and coordination with behavioral care.
No single approach works for everyone, and the most effective plans are individualized. What flare management looks like for a person with IBS-D and high anxiety may look quite different from what helps someone with IBS-C and sleep disruption.
A Note to Anyone in the Middle of a Flare
If you are reading this during a hard stretch, when your gut is loud and your life feels narrower than it should, it is worth saying directly: what you are experiencing is real, it has a biological basis that is increasingly well understood, and it is treatable. You do not have to simply endure it.
At GI Psychology, we specialize in the behavioral treatment of IBS and other disorders of gut-brain interaction, working with both adults and children across the lifespan. Our approach is grounded in the evidence and tailored to the whole person, not just the symptom list.
Learn more by exploring our resources, scheduling a free 15-minute phone consultation, or reaching out at admin@gipsychology.com.
References
Ballou, S., & Keefer, L. (2017). Psychological Interventions for Irritable Bowel Syndrome and Inflammatory Bowel Diseases. Clinical and translational gastroenterology, 8(1), e214.
Drossman D. A. (2016). Functional Gastrointestinal Disorders: History, Pathophysiology, Clinical Features and Rome IV. Gastroenterology, S0016-5085(16)00223-7. Advance online publication.
Ford, A. C., Moayyedi, P., Lacy, B. E., Lembo, A. J., Saito, Y. A., Schiller, L. R., Soffer, E. E., Spiegel, B. M., Quigley, E. M., & Task Force on the Management of Functional Bowel Disorders (2014). American College of Gastroenterology monograph on the management of irritable bowel syndrome and chronic idiopathic constipation. The American journal of gastroenterology, 109 Suppl 1, S2–S27.
Heitkemper, M. M., & Chang, L. (2009). Do fluctuations in ovarian hormones affect gastrointestinal symptoms in women with irritable bowel syndrome?. Gender medicine, 6 Suppl 2(Suppl 2), 152–167.
Lacy, B. E., Mearin, F., Chang, L., Chey, W. D., Lembo, A. J., Simrén, M., & Spiller, R. (2016). Bowel disorders. Gastroenterology, 150(6), 1393–1407.
Mayer E. A. (2011). Gut feelings: the emerging biology of gut-brain communication. Nature reviews. Neuroscience, 12(8), 453–466.
Mayer, E. A., & Tillisch, K. (2011). The brain-gut axis in abdominal pain syndromes. Annual review of medicine, 62, 381–396.
Moser, G., Trägner, S., Gajowniczek, E. E., Mikulits, A., Michalski, M., Kazemi-Shirazi, L., Kulnigg-Dabsch, S., Führer, M., Ponocny-Seliger, E., Dejaco, C., & Miehsler, W. (2013). Long-term success of GUT-directed group hypnosis for patients with refractory irritable bowel syndrome: a randomized controlled trial. The American journal of gastroenterology, 108(4), 602–609.