What Causes Constipation?

Constipation is a common digestive issue that affects people of all ages. Medically, it’s defined as having fewer than three bowel movements per week or experiencing hard, dry stools that are difficult to pass. Understanding what causes constipation can help you make small changes to relieve symptoms and improve your overall gut health.

1. Diet and Fluids

What you eat and drink plays a central role in bowel function. Key dietary factors include:

• Low fiber intake
  • Fiber adds bulk to stool and helps it move through the intestines.
  • Diets heavy in processed foods, white rice or white bread often lack adequate fiber.

• Inadequate hydration
  • Water softens stool.
  • Dehydration or not drinking enough fluids can lead to hard, dry stools.

• Excessive dairy or meat
  • High intake of cheese, milk or fatty meats may slow digestion.
  • Balancing protein with fruits, vegetables and whole grains is crucial.

2. Lifestyle and Habits

Modern lifestyles can inadvertently contribute to sluggish bowels:

• Sedentary behavior
  • Sitting for long periods reduces intestinal contractions that move stool.
  • Regular movement—walking, stretching or light exercise—stimulates digestion.

• Ignoring the urge to go
  • Suppressing bowel urges trains the body to delay.
  • Over time, signals weaken and stool accumulates in the colon.

• Travel, work schedules or stress
  • Changes in routine can disrupt healthy bathroom habits.
  • Stress hormones slow gut motility in some people.

3. Medications and Supplements

Certain treatments are known to cause constipation as a side effect:

• Pain medications
  • Opioids (e.g., codeine, oxycodone) significantly slow intestinal movement.
• Antacids containing calcium or aluminum
  • Common heartburn remedies can harden stools.
• Iron or calcium supplements
  • Often prescribed for anemia or osteoporosis, they may cause constipation.
• Antidepressants and antipsychotics
  • Some affect neurotransmitters that regulate gut function.
• Diuretics
  • Can lead to dehydration if fluid intake isn’t adjusted accordingly.

If you suspect a medication is contributing to constipation, do not stop it abruptly. Talk to your doctor about alternatives or strategies to manage symptoms.

4. Medical Conditions

Underlying health problems can interfere with normal bowel function:

• Irritable Bowel Syndrome (IBS)
  • A functional disorder causing cramping, bloating and changes in bowel habits.
  • The “constipation-predominant” subtype often leads to infrequent or painful stools.

• Hypothyroidism
  • Low thyroid hormone slows metabolism, including gut motility.
  • Other signs include fatigue, weight gain and cold intolerance.

• Diabetes
  • High blood sugar can damage nerves (diabetic neuropathy), including those that control digestion.
  • May also lead to dehydration and electrolyte imbalances.

• Neurological disorders
  • Conditions such as Parkinson’s disease, multiple sclerosis or spinal cord injuries can impair nerve signals to the bowel.

• Colon or rectal problems
  • Narrowing of the colon (strictures), tumors or scar tissue can block or slow passage of stool.
  • Hemorrhoids or anal fissures may cause pain that leads someone to delay bowel movements.

5. Functional Constipation

Sometimes no clear structural or metabolic cause is found. Functional constipation may involve:

• Slow-transit constipation
  • The colon muscle contractions are weaker or less frequent.
• Dyssynergic defecation
  • Pelvic floor muscles don’t coordinate properly to expel stool.
• Normal-transit constipation
  • Stool moves at a normal pace but feels hard and difficult to pass.

Functional types are diagnosed based on symptom patterns, physical exams and sometimes specialized tests like anorectal manometry.

6. Life Stages and Risk Factors

Certain groups are more susceptible to constipation:

• Infants and toddlers
  • Diet changes (switching from milk to solids) can cause temporary constipation.
• Pregnant individuals
  • Hormonal shifts and pressure on the intestines by the growing uterus slow bowel movements.
• Older adults
  • Slower metabolism, less physical activity and more medications increase risk.
• People with limited mobility
  • Bedridden or wheelchair-bound individuals may struggle with regular bowel movements.

7. When to Seek Help

Most constipation is mild and improves with diet or lifestyle changes. However, see a doctor promptly if you experience:

• Severe abdominal pain or bloating
• Blood in your stool or black, tarry stools
• Unexplained weight loss
• A sudden change in bowel habits lasting more than two weeks
• Vomiting alongside constipation

These could signal more serious diseases, such as bowel obstruction, inflammatory bowel disease or colorectal cancer.

8. Next Steps and Resources

If you’re unsure what’s behind your symptoms, consider a free, online symptom check, using the doctor approved Ubie Symptom Checker. This tool can guide you on possible causes and when to seek medical attention.

Finally, always speak to a doctor about anything that could be life-threatening or serious. Proper diagnosis and individualized treatment—whether it’s a simple diet tweak or further medical evaluation—are key to getting relief and protecting your health.