What Causes Chronic Constipation?

Introduction: What Is Chronic Constipation and Why It Matters?

Chronic constipation means having fewer than three stools per week, along with hard stools that are difficult to pass, for at least three months. It goes beyond the occasional off day. People who experience constipation on a chronic basis often deal with persistent stomach pain, bloating, and the frustrating sense that they haven’t fully emptied their bowels. Over time, the condition can chip away at quality of life, affecting everything from work to social plans to sleep.

This is not a rare problem. Chronic constipation affects up to 27% of the population, with higher rates among women and adults over age 65. So what causes chronic constipation? At a high level, the answer usually falls into a few categories:

• Stool moves slowly through the large intestine, allowing the body to absorb too much water and leaving behind dry, hard waste.
• Pelvic floor muscles fail to coordinate properly during a bowel movement, creating an outlet blockage.
• Medications-from opioids to allergy medications to psychiatric medications-trigger constipation as a side effect.
• Underlying medical conditions such as hypothyroidism, diabetes, or neurologic disorders disrupt the normal nervous system signals that keep things moving.
• Lifestyle factors like a low-fiber diet, not drinking enough water, and physical inactivity compound the problem.

Early evaluation matters because the right treatment depends entirely on identifying the right cause. At Advanced Research Institute, we focus on evidence-based evaluation and, when appropriate, clinical trials that explore new options for constipation relief, supported by our patient-centered research organization.

How Chronic Constipation Happens Inside the Gut

In normal digestion, food travels from the stomach through the small intestine and into the colon, where the body absorbs remaining water and nutrients. Muscle contractions push stool toward the rectum, and a bowel movement usually follows within one to three days. When this system works, most people poop somewhere between three times a day and three times a week-both ends of that range are considered normal.

Constipation occurs when this process breaks down. The two key mechanisms are:

• Slow-transit constipation. Contractions in the colon are weak, infrequent, or poorly coordinated, so stool moves slowly through the digestive tract. Because the stool sits in the colon longer, the body absorbs too much water, leaving behind dry, compacted waste that is painful to pass.
• Outlet or evacuation dysfunction. The stool reaches the rectum on time, but the muscles responsible for expelling it-particularly the pelvic floor muscles-don’t relax or coordinate properly. The result is intense straining, a feeling of blockage, and defecation problems despite the urge to go.

These mechanisms are often identified through a careful bowel movement history and, when initial treatment fails, specialized transit and manometry testing. Many patients have overlap between the two, which is why a thorough workup is so valuable.

Common Symptoms of Chronic Constipation

Symptoms of constipation can be both physical-pain, cramping, pressure-and functional, relating to how often and how completely you pass stool. The Rome IV criteria diagnose chronic constipation based on specific symptoms present for at least three months. Core signs include:

• Fewer than three bowel movements per week for at least several weeks (or three weeks or longer).
• Hard, lumpy, or dry stools that are painful and difficult to pass.
• Straining or spending a long time on the toilet to have any stool.
• A sensation that you haven’t completely emptied your bowels, or that something is blocking the anus.
• Abdominal discomfort, cramping, or a tendency to feel bloated after meals.

Additional signs to watch for: bleeding from hemorrhoids or anal fissures, nausea, decreased appetite, or discomfort that improves only after you’ve emptied your bowels. You may also notice you need more toilet paper than usual due to incomplete evacuation.

Chronic constipation is generally defined by having two or more of these symptoms persistently. Keeping a simple bowel movement history-noting frequency, stool texture, pain, and any blood-gives your doctor a much clearer picture than a vague report of “not going enough.”

Primary Gut-Related Causes: When the Problem Starts in the Colon

Primary causes of chronic constipation are rooted in how the gut and rectum function, rather than in a disease elsewhere in the body. The three main categories are slow-transit constipation, pelvic floor dysfunction, and irritable bowel syndrome with constipation.

Slow-transit constipation involves reduced or uncoordinated muscle contractions in the colon. Research has found that patients with this subtype often have fewer interstitial cells of Cajal-the pacemaker cells that drive gut motility-and diminished nerve cell density in the colon wall. Symptoms include infrequent regular bowel movements, less urge to go, and hard stools. It is often seen more in women and can begin in the teens or early adulthood, persisting for years.

Pelvic floor dysfunction is an evacuation disorder in which pelvic floor muscles fail to relax or paradoxically tighten when you try to pass stool. People with this condition often describe intense straining, feeling blocked, and needing manual maneuvers to have a bowel movement. Biofeedback therapy-a non-surgical treatment with strong research support-can retrain these muscles and restore coordination. It is one of the most effective interventions the American Gastroenterological Association recommends for outlet constipation.

Irritable bowel syndrome with constipation (IBS-C) combines chronic abdominal pain linked to bowel habits with hard or infrequent stools. In IBS-C, the gut may be extra sensitive to stretching and distension, and stool moves too slowly even though standard tests often look normal. Irritable bowel syndrome is a medical condition that can cause constipation alongside pain, distinguishing it from simple functional constipation.

Secondary Causes: Medications and Medical Conditions That Cause Constipation

Many people develop chronic constipation because of something outside the gut-medicines they take or other medical conditions they live with. Certain medications can cause chronic constipation as a side effect, including:

• Opioid pain relievers (hydrocodone, oxycodone, morphine)-opioid pain relievers commonly cause constipation, affecting roughly 25–40% of non-cancer users.
• Certain antidepressants, antipsychotics, and antinausea medications with anticholinergic properties.
• Calcium-channel blockers prescribed for high blood pressure (e.g., verapamil, nifedipine).
• Iron supplements, calcium supplements, and antacids containing aluminum or calcium.
• Some allergy medications and psychiatric medications that slow the digestive tract.

Key medical conditions that cause constipation include hormonal problems such as hypothyroidism or uncontrolled diabetes, which alter gut motility. Neurologic conditions-Parkinson’s disease, spinal cord injuries, multiple sclerosis-affect the nervous system pathways controlling bowel movements. Metabolic and electrolyte imbalances like high calcium or low potassium can also worsen constipation. Structural issues such as strictures, rectoceles, or prior pelvic surgery physically impede stool passage.

Among the more serious but less common causes is colon cancer, especially when constipation is new, rapidly worsening, or paired with weight loss, anemia, or blood mixed in the stool. Inflammatory or scarring diseases that narrow the colon, including Crohn’s disease that may require advanced therapies, can produce similar sudden changes in bowel habits.

Often chronic constipation is multifactorial. Aging, reduced mobility, blood pressure medications, and dietary decline frequently combine to produce symptoms no single factor would cause alone.

Lifestyle and Behavioral Factors That Can Lead to Chronic Constipation

Everyday habits are a frequent-and often underestimated-driver of constipation, and they are usually the first area to address for constipation relief. Chronic constipation can be exacerbated by stress and changes in routine, making lifestyle awareness essential.

• Low-fiber diet. Dietary fiber deficiency can lead to chronic constipation. A diet heavy in processed foods and low in high fiber foods like fruits, vegetables, and whole grains fails to provide the bulk that stimulates colonic contractions.
• Inadequate fluids. Not drinking enough water can cause constipation because the colon pulls moisture from stool when the body is under-hydrated. This is especially relevant in hot, arid climates like Utah and Nevada, or for people who rely heavily on caffeine or take diuretics.
• Physical inactivity. Regular physical inactivity is a common cause of chronic constipation. Sedentary desk work, prolonged bed rest after surgery, or limited mobility in older adults all slow gut transit.
• Ignoring the urge. Ignoring the urge to pass stool-because of a busy schedule, travel, or limited restroom access-trains the rectum to stop sending signals. Ignoring the feeling of needing to use the bathroom can weaken the body’s signals over time, making it progressively harder to maintain regular bowel movements.
• Poor toilet posture. Using the toilet in a rushed or uncomfortable position can cause pelvic floor muscles to tighten rather than relax.
• Life-stage changes. Pregnancy can lead to hormonal and physical changes that cause constipation. Aging, especially after 65, brings decreased mobility, multiple medications, and accumulating medical conditions that all contribute.

Changing these factors-diet, enough fluids, daily routine activity, and toilet habits-is almost always recommended before or alongside medications to treat constipation.

How Doctors Diagnose the Cause of Chronic Constipation

Identifying what causes chronic constipation starts with a careful conversation and physical exam, not a battery of tests. Regular gastrointestinal evaluation is essential if chronic constipation persists despite self-care measures. Your doctor will typically begin with:

• A detailed bowel movement history: frequency, stool consistency, straining, time spent on the toilet, and use of stimulant laxatives, stool softeners, or home remedies.
• A review of diet, daily fluid intake, physical activity level, and all current medications.
• Questions about red-flag symptoms of constipation: blood in stool, weight loss, anemia, or a strong family history of colon cancer.

Physical exams include an abdominal assessment to feel for stool buildup or tenderness and a digital rectal exam to check for anal fissures, hemorrhoids, masses, or pelvic floor muscle coordination.

If the cause remains unclear or initial treatment fails, tests may include:

• Basic blood work to check thyroid function, electrolytes (calcium, potassium), and blood glucose.
• Colonoscopy for appropriate ages or risk factors, to rule out colon cancer or polyps.
• Transit studies such as sitz marker tests to measure how quickly stool moves through the colon.
• Anorectal manometry and imaging like MRI defecography to evaluate pelvic floor muscles and rectal function.

At Advanced Research Institute, board-certified physicians use these evaluations to match people to clinical trials when standard options haven’t provided enough relief.

When Constipation Signals Something Serious (and When to Seek Help)

Most chronic constipation is uncomfortable but not dangerous. However, certain symptoms should prompt immediate health care attention:

• New or rapidly worsening constipation in someone over about age 45–50.
• Constipation with unintentional weight loss, fatigue, or iron-deficiency anemia.
• Blood in the stool-red or black-or mucus mixed with stool.
• Severe pain, vomiting, or inability to pass gas, which can signal fecal impaction or bowel obstruction.
• A strong family history of colon cancer or inflammatory bowel disease alongside new bowel changes.

These red flags may prompt testing to rule out colon cancer, strictures, or other serious conditions, or to investigate early signs of Crohn’s disease. Constipation may also warrant a routine visit when it lasts more than three months despite home remedies, when you depend on laxatives for any bowel movement, or when it significantly affects your daily routine-missing work, avoiding social events, or constant discomfort.

Advanced Research Institute coordinates with gastroenterologists and primary care clinicians in Utah and Nevada, particularly when someone might qualify for a constipation or irritable bowel syndrome clinical research study. If you’re wondering whether clinical trials are safe, the data is reassuring-trials are closely overseen by the FDA and independent ethics boards, and our clinical trial FAQ explains the safeguards in more detail.

Improving and Preventing Chronic Constipation: Practical Steps and Advanced Options

Long-term constipation relief usually combines lifestyle changes, targeted treatment, and-when appropriate-clinical research. Managing chronic constipation often involves increasing dietary fiber, hydration, and exercise as the foundation. Dietary changes can help treat constipation effectively before anything else is needed.

Practical prevention strategies:

• Increase high fiber foods gradually-beans, oats, berries, leafy greens-to prevent constipation without excess gas.
• Drink enough water daily, adjusting for climate, activity level, and other medical conditions. Drinking enough water can alleviate constipation symptoms noticeably.
• Exercise regularly. Even daily walking or gentle stretching helps stimulate a bowel movement and keep stool moving.
• Respond promptly to the urge to go. Use a supported posture on the toilet (knees slightly above hips with a footstool) to help the body relax.

Medical treatments:

• Over-the-counter fiber supplements, stool softeners, and gentle osmotic laxatives under clinician guidance are first-line options. Mild laxatives may be used if dietary changes fail, though stimulant laxatives are rarely needed on a long-term basis.
• Prescription medications-secretagogues like linaclotide or prokinetics like prucalopride-increase fluid in the intestines or improve motility for people who don’t respond to basic measures. Surgery is rarely needed and reserved for confirmed slow-transit cases.

Pelvic floor therapies:

• Biofeedback therapy with a trained provider helps patients learn to relax and coordinate pelvic floor muscles during a bowel movement. It is non-surgical, well-studied, and effective for chronic outlet constipation. Biofeedback therapy can help with evacuation disorders when other approaches fall short.

ARI’s role:

Advanced Research Institute participates in constipation and irritable bowel syndrome clinical trials and other studies overseen by the FDA and ethics boards. Qualified participants may receive no-cost study-related medical care, diagnostic testing, and close follow-up by research professionals. Learn more about our clinical trials or book a free consultation to see if you qualify.

Even for long-standing chronic constipation, new treatments and research studies-from microbiome-based therapies to novel prokinetics-continue to expand options. The National Institute of Digestive and Kidney Diseases and the American College of Gastroenterology both emphasize that most people can find meaningful relief when causes are properly identified and addressed. If standard approaches haven’t worked, a clinical trial may offer the next step forward.

We Have a Study on Chronic Idiopathic Constipation — See If You Qualify

Still Struggling With Chronic Constipation?

If chronic constipation continues to affect your daily life despite changes to your diet, hydration, or current treatment, you may have other options. Advanced Research Institute conducts clinical research studies evaluating potential new treatments for chronic constipation and related digestive conditions.

Qualified participants may receive study-related medical care and testing at no cost while helping researchers explore new treatment options.

See if a clinical trial may be right for you.