Hemorrhoids get worse when the cushions of tissue inside the anal canal face sustained or repeated pressure, and the list of things that create that pressure is longer than most people expect. Straining on the toilet, a low-fiber diet, pregnancy, obesity, chronic cough, prolonged sitting, and even scrolling your phone in the bathroom all feed into the same basic problem: too much force pushing on vascular tissue that has already lost some of its structural support. The science behind these triggers reveals why hemorrhoid flare-ups often cluster and why fixing just one habit rarely solves the problem.
How the Underlying Damage Works
Hemorrhoids are not simply swollen veins. The current understanding is that the vascular cushions lining the anal canal become abnormally dilated and distorted, and the connective tissue that normally anchors them in place starts breaking down.1PubMed Central. Hemorrhoids: from basic pathophysiology to clinical management Think of it like a hammock whose ropes are fraying: the tissue sags, the blood vessels swell, and each new insult stretches things further. Modern research describes a complex interplay of vascular congestion, mechanical failure, and inflammation that worsens in stages.2Quality in Sport. Etiology Based and Stage-Adapted Management of Hemorrhoidal Disease: Clinical Outcomes, Functional Impact, and Quality of Life — A Narrative Review That progression is what gives hemorrhoid triggers their cumulative power: anything that increases pressure or inflammation in the area is working against tissue that is already compromised.
Straining and the Pressure It Creates
Straining during a bowel movement is the trigger most people associate with hemorrhoids, and the research backs that up in concrete terms. Measurements of anal canal pressure show that people with hemorrhoids experience significantly higher pressures during straining and coughing than people without them. In one study, pressure during straining was roughly 80 cmHâ‚‚O in hemorrhoid patients compared to about 55 cmHâ‚‚O in healthy controls. Even more telling, in about 60 percent of patients the pressure stayed elevated after straining ended, taking 18 to 36 seconds to return to baseline, while this did not happen in any of the healthy subjects.3PubMed. Hypertensive anal cushions as a cause of the high anal canal pressures in patients with haemorrhoids
That lingering elevated pressure matters. It means the vascular cushions are not getting a clean recovery between episodes. Every hard push during a bowel movement effectively stretches them a little further, and they snap back a little less each time. Anything that forces you to strain harder or more often, whether that is constipation, hard stools, or trying to “finish” when your body is not ready, feeds directly into this cycle.
Low Fiber, Low Fluid, and Constipation
Diet is one of the most modifiable triggers, and the data here is striking. A study comparing hemorrhoid patients with healthy controls found that eating fewer than 12 grams of fiber per day was linked to a seven-fold increase in the odds of developing internal hemorrhoids. Drinking less than two liters of water daily carried an even larger association, roughly an eight-fold increase in risk.4La Tunisie Médicale. Dietary habits associated with internal hemorrhoidal disease Constipation was found in nearly all of the hemorrhoid patients, and the patients consistently ate fewer vegetables, fruits, and cereals than controls.
That said, the relationship between fiber, constipation, and hemorrhoids is not as straightforward as older medical literature suggested. A review in a major gastroenterology journal noted that while low fiber and constipation have long been thought to increase hemorrhoid risk, the link has not been definitively proven in the way many clinicians assume.5PubMed Central. Rethinking What We Know About Hemorrhoids The evidence is strong enough that boosting fiber and fluid intake remains standard first-line advice, but the picture is more complicated than “eat more fiber, problem solved.” Constipation is a downstream effect of many things beyond diet, including medications, inactivity, and neurological conditions, and hemorrhoid flares can happen in people who eat plenty of fiber if other triggers are at play.
Diarrhea Is a Trigger Too
Most people think of constipation as the only bowel-related problem that worsens hemorrhoids. Diarrhea gets overlooked, and that is a genuine blind spot. Frequent loose stools irritate the anal canal, and the repeated urgency and pushing that come with diarrheal episodes create their own form of straining. A large database study found that diseases associated with diarrhea were significantly linked to hemorrhoid diagnoses, with an odds ratio of about 1.3. Constipation-related conditions had a somewhat higher association at about 1.5, but the diarrhea connection was clearly present and statistically meaningful.6PubMed. Associations between hemorrhoids and other diagnoses Separate research specifically examining diarrheal disorders supported the idea that diarrhea plays a pathogenic role in hemorrhoid development.7PubMed. Association of hemorrhoidal disease with diarrheal disorders: potential pathogenic relationship?
This has a practical consequence. If you swing from constipation to loose stools by overcorrecting with laxatives or stool softeners, you may be trading one hemorrhoid trigger for another. One review in gastroenterology noted that bulking agents and laxatives should be used cautiously in people with anal symptoms, because excessively loosening stools can create its own set of problems, including soilage and irritation from prolapsing tissue.8Gastroenterology. Medical management of fecal incontinence The goal is soft, formed stools that pass easily, not a pendulum swing between extremes.
Prolonged Toilet Sitting and Smartphone Use
Spending too long on the toilet is one of those triggers that sounds trivial until you see the data. Sitting on a toilet seat removes the support the surrounding muscles normally provide to the pelvic floor, and the longer you sit, the more the anal cushions bear the load of gravity. Modern bathroom habits have made this worse because phones have turned the toilet into a reading room.
A study published in 2025 found that people who used smartphones on the toilet were far more likely to stay longer than five minutes per visit: about 37 percent of phone users exceeded five minutes, compared to just 7 percent of non-phone users. After adjusting for age, sex, body mass, exercise, straining, and fiber intake, smartphone use on the toilet was associated with a 46 percent increase in hemorrhoid risk.9PubMed Central. Smartphone use on the toilet and the risk of hemorrhoids An earlier study found a similar pattern, reporting that each additional minute spent using a phone in the bathroom increased the incidence of hemorrhoid disease. Spending more than ten minutes per session and always bringing the phone to the bathroom were both associated with a hemorrhoid diagnosis.10Turkish Journal of Colorectal Diseases. The Relationship Between Smartphone Use in the Lavatory and Hemorrhoidal Disease
The practical takeaway is one that colorectal surgeons have been repeating for years: use the toilet when you feel the urge, do your business, and leave. If nothing is happening after a few minutes, get up and try again later. The scrolling, reading, and gaming that extend bathroom visits to ten or fifteen minutes put sustained low-level pressure on tissue that is already vulnerable.
Pregnancy and the Postpartum Period
Pregnancy is one of the most powerful hemorrhoid triggers, and it hits from multiple directions. The growing uterus increases intra-abdominal pressure. Hormonal changes relax blood vessel walls and slow gut motility, promoting constipation. Then childbirth itself adds the intense straining of pushing during delivery. Research estimates that hemorrhoids and anal fissures affect roughly 40 percent of pregnant and postpartum women, most commonly in the third trimester and in the first couple of days after delivery.11PubMed Central. Perianal Diseases in Pregnancy and After Childbirth: Frequency, Risk Factors, Impact on Women’s Quality of Life and Treatment Methods
Several specific risk factors stand out within this group: constipation during pregnancy, having had perianal problems in a previous pregnancy, instrumental delivery (forceps or vacuum), straining for more than twenty minutes during labor, and a heavier newborn (over about 3,800 grams). Many of these factors are difficult to control, but addressing constipation early in pregnancy with adequate fiber and fluid is one intervention that can reduce the cumulative strain on hemorrhoidal tissue before delivery compounds the problem.
Body Weight and Abdominal Fat
Carrying excess weight, particularly around the midsection, raises baseline intra-abdominal pressure in a way that mirrors the mechanism behind straining and chronic cough. A large Korean national health survey found that both general obesity and abdominal obesity were associated with higher hemorrhoid risk.12PubMed Central. Factors Associated with Hemorrhoids in Korean Adults: Korean National Health and Nutrition Examination Survey A more recent Mendelian randomization study, which uses genetic variation to test whether the relationship is likely causal rather than just a correlation, found positive effects of genetically determined BMI, body fat percentage, waist circumference, and waist-to-hip ratio on hemorrhoid risk.13PubMed Central. Causal association between adiposity and hemorrhoids: a Mendelian randomization study The genetic evidence is particularly interesting because it suggests the link goes beyond shared lifestyle factors: the body fat itself, and the physical pressure it creates, appears to drive hemorrhoid development.
The effect sizes are modest on a per-individual basis, but across a population they add up. For someone who already has symptomatic hemorrhoids, excess abdominal weight is one more source of constant pressure working against recovery.
Chronic Cough and Lung Conditions
Any condition that causes repeated, forceful coughing raises intra-abdominal pressure in exactly the same way that straining on the toilet does. This is why chronic obstructive pulmonary disease (COPD) has been linked to hemorrhoid development. Researchers in a large cohort study noted that the chronic cough and labored breathing associated with COPD were likely related to increased intra-abdominal pressure that aggravated hemorrhoidal tissue.14PubMed Central. Association of chronic obstructive pulmonary disease and hemorrhoids: A nationwide cohort study The same pressure study mentioned earlier showed that coughing pressures in hemorrhoid patients were roughly double those in healthy controls.3PubMed. Hypertensive anal cushions as a cause of the high anal canal pressures in patients with haemorrhoids
This extends beyond COPD. Seasonal allergies that trigger persistent coughing, chronic bronchitis, asthma that is poorly controlled, and even a lingering cold can all temporarily worsen hemorrhoid symptoms. People who notice flare-ups during respiratory illness are not imagining it. If you have existing hemorrhoids and a cough that will not quit, treating the cough is part of treating the hemorrhoids.
Stress, Anxiety, and the Pelvic Floor
The connection between mental health and hemorrhoids is not one that gets much attention, but there is a plausible mechanism and emerging evidence for it. Anxiety tends to increase muscle tension throughout the body, and the pelvic floor is no exception. Research examining depression and anxiety symptom networks in hemorrhoid patients has pointed to pelvic floor hypertonicity, where the muscles of the pelvic floor remain chronically tight, as a potential somatic bridge between psychological distress and anorectal problems.15PubMed Central. Depression and anxiety symptom networks in hemorrhoid patients: evidence from the UK biobank Stress-related changes to the gut microbiome may also play a role, though that research is still early.
In practical terms, this means that someone going through a high-stress period may notice their hemorrhoid symptoms worsening even if their diet and toilet habits have not changed. Chronic tension in the pelvic floor can increase resting anal canal pressure, which works against hemorrhoidal tissue in the same way that straining does, just more subtly and continuously. Relaxation techniques, pelvic floor physical therapy, and treating underlying anxiety are not typical hemorrhoid treatments, but they may help break the cycle in people who clench without realizing it.
When It Might Not Be Hemorrhoids
One reason hemorrhoids seem to keep getting worse despite treatment is that, in some cases, the problem is not hemorrhoids at all. Rectal varices, which are dilated veins associated with liver disease and portal hypertension, can look and feel similar to hemorrhoids but require entirely different management. Distinguishing the two is clinically important because the treatment approaches differ substantially.16PubMed Central. Rectal varices vs hemorrhoids-diagnosis and management It is worth noting, though, that portal hypertension has been shown not to be a cause of ordinary hemorrhoids, so simply having liver disease does not mean your hemorrhoids are actually varices.17PubMed. What are hemorrhoids and what is their relationship to the portal venous system?
The same diagnostic uncertainty applies to other conditions that mimic hemorrhoid symptoms: anal fissures, perianal abscesses, skin tags, and, rarely, colorectal cancer. Bleeding that does not improve with conservative treatment, a sudden change in bowel habits, or symptoms that feel different from previous flare-ups all warrant a proper evaluation rather than more over-the-counter cream.
Why Triggers Tend to Stack
What makes hemorrhoid management frustrating is that very few people deal with just one trigger at a time. A person with a sedentary desk job may also eat a low-fiber diet, spend extra time on the toilet scrolling social media, and carry excess abdominal weight. A pregnant person dealing with hormonal constipation is simultaneously contending with increased abdominal pressure and, potentially, the stress of a major life change. A COPD patient who coughs frequently might also be taking medications that cause constipation.
The association data reflects this stacking. The large database study that examined conditions co-occurring with hemorrhoids identified five broad categories of associated diagnoses: diarrheal diseases, spinal cord injuries, constipation-related conditions, other anorectal diseases, and conditions that were likely consequences of the hemorrhoids themselves.6PubMed. Associations between hemorrhoids and other diagnoses That range of associations underscores how many different pathways converge on the same vulnerable tissue. Addressing hemorrhoid triggers effectively usually means identifying which ones are active in your specific situation and tackling several at once, rather than expecting a single change to solve the problem.
Spinal Cord Injuries and Nerve-Related Triggers
One association that surprises many people is the link between spinal cord injuries and hemorrhoids. That same large database study found a statistically significant association between the two, likely because spinal cord damage disrupts normal bowel motility, sensation, and voluntary control of the pelvic floor muscles.6PubMed. Associations between hemorrhoids and other diagnoses People with spinal cord injuries often deal with neurogenic bowel dysfunction, which can manifest as chronic constipation, prolonged straining during bowel programs, and extended time spent on the toilet or commode. All of these are known hemorrhoid triggers, but they occur in a context where the usual advice of “just eat more fiber and don’t strain” may not be sufficient.
This extends in milder form to anyone with chronic nerve issues affecting the lower spine or pelvic floor. Conditions that alter how you sense and control bowel movements can quietly set the stage for hemorrhoid problems, and they deserve a conversation with a specialist rather than the standard lifestyle pamphlet.