Hemorrhoids develop when the cushions of tissue lining the anal canal slide out of position and become swollen, and the causes behind that process are more varied than most people realize. Straining during bowel movements gets the most attention, but chronic diarrhea, prolonged toilet sitting, pregnancy, aging connective tissue, genetics, and even your workout routine all play a role. The interplay of these factors explains why hemorrhoids are so common and why fixing just one habit does not always solve the problem.
What Hemorrhoids Actually Are
A widespread misconception is that hemorrhoids are abnormal growths, like varicose veins that pop up where they should not be. In reality, everyone has hemorrhoidal tissue. The anal canal contains cushions made of blood vessels, smooth muscle, and connective tissue that help with continence by forming a seal when the sphincter is closed. Hemorrhoidal disease happens when these cushions get displaced downward and become engorged with blood.1PubMed. Haemorrhoids: pathology, pathophysiology and aetiology That distinction matters because it shifts the question from “why did something new appear?” to “why did something normal break down?”
The breakdown has two broad components. First, the connective tissue anchoring the cushions weakens or stretches, letting the tissue bulge into the anal canal. Second, the blood vessels within those cushions become congested, swelling and sometimes bleeding. Different causes act on one or both of these components, which is why no single explanation covers every case.
Straining and Constipation
Straining is the cause people hear about most, and the evidence does support the connection. A large screening-colonoscopy study found that people with hemorrhoids were roughly 60 percent more likely to report straining during bowel movements than people without them. Hard stools and a feeling of incomplete emptying were also more common among hemorrhoid cases.2PLoS ONE. Risk Factors for Hemorrhoids on Screening Colonoscopy When you bear down forcefully, you spike the pressure inside the abdomen and the veins of the anal canal. Repeat that often enough and the cushions stretch, lose their support, and prolapse.
That said, the relationship between constipation and hemorrhoids is less ironclad than the textbooks long implied. A review in a major gastroenterology journal noted that a low-fiber diet and constipation have historically been assumed to raise hemorrhoid risk, but the link remains more speculative than proven.3PubMed Central. Rethinking What We Know About Hemorrhoids One reason is that many people with constipation never develop hemorrhoids, and many hemorrhoid patients have perfectly normal bowel habits. Straining matters, but it is not the whole story.
Diet and Fiber
If straining is the mechanism, fiber is the most commonly recommended countermeasure. The logic is straightforward: bulkier, softer stools pass more easily, so you push less. Some evidence backs this up. The same colonoscopy screening study found that high grain fiber intake was associated with a modestly lower risk of hemorrhoids compared with the lowest intake levels.2PLoS ONE. Risk Factors for Hemorrhoids on Screening Colonoscopy
The catch is that the protective effect was modest. Fiber helps, but it is not a guaranteed shield. Other dietary factors matter too. Adequate water intake keeps stool soft independently of fiber. Alcohol and spicy foods are often blamed anecdotally, though the evidence for those is weaker and inconsistent. Where fiber seems to have the clearest benefit is as a treatment strategy for people who already have symptoms: increasing fiber and fluid intake is one of the first lines of conservative management and can reduce bleeding and discomfort enough that many people avoid procedures.
Diarrhea Is a Risk Factor Too
This is one that surprises people. Constipation gets all the attention, but chronic diarrhea can be just as damaging to the anal cushions. Research has found strong associations between hemorrhoidal disease and several diarrheal disorders, including ulcerative colitis, noninfectious gastroenteritis, and functional diarrhea.4PubMed. Association of hemorrhoidal disease with diarrheal disorders: potential pathogenic relationship? Frequent loose stools mean repeated trips to the toilet, more time sitting on the seat, and often a degree of straining to fully empty. Liquid stool can also irritate the anal lining, promoting inflammation that contributes to cushion swelling.
The practical takeaway: if your hemorrhoids keep flaring even though you eat plenty of fiber and your stools are not hard, the issue may be on the opposite end of the spectrum. Irritable bowel syndrome with diarrhea, inflammatory bowel disease, and even overuse of laxatives can all contribute.
Prolonged Toilet Sitting and Smartphone Habits
Spending extra time on the toilet is a habit many people do not think twice about, especially since phones turned bathrooms into reading rooms. But a standard toilet seat provides no support to the pelvic floor. When you sit on one for extended periods, the unsupported position allows pressure to build in the hemorrhoidal cushions. Over time, those cushions can become engorged and progress into symptomatic hemorrhoids.5PubMed Central. Smartphone use on the toilet and the risk of hemorrhoids
This is not just theoretical hand-wringing. Research specifically examining smartphone use on the toilet identified it as a risk factor for hemorrhoidal disease, likely because phones extend toilet-sitting time well beyond what is needed for the actual bowel movement. The fix is simple in theory: use the toilet, finish, get up. Scrolling through social media on the couch puts no downward pressure on your anal cushions. Doing it on the toilet does.
Pregnancy and the Postpartum Period
Hemorrhoids are extremely common in the later stages of pregnancy. The prevalence among pregnant women is high in late pregnancy, driven by a combination of factors that converge at once.6PubMed. Comparing topical hydrocortisone cream with Hai’s Perianal Support in managing symptomatic hemorrhoids in pregnancy The growing uterus compresses the veins that drain the pelvic region, raising pressure in the hemorrhoidal vessels. Hormonal changes during pregnancy soften connective tissue throughout the body, weakening the anchoring system of the anal cushions. And constipation, which many pregnant people experience due to iron supplements and hormonal shifts, adds straining on top of everything else.
Labor and vaginal delivery compound the problem further. The intense pushing involved in delivery generates enormous abdominal pressure over a sustained period, which can enlarge existing hemorrhoids or create new ones. Many postpartum hemorrhoids resolve on their own as hormones normalize and pelvic pressure drops, but for some people they persist and need treatment. If you are pregnant and already prone to hemorrhoids, keeping stools soft and avoiding prolonged toilet sitting are the most practical things you can do, since you cannot eliminate the other mechanical pressures of pregnancy.
Aging and Connective Tissue Breakdown
Hemorrhoid symptoms become more common as people age, and the reason is structural. The connective tissue that anchors the anal cushions in place deteriorates over time. As this support weakens, the cushions bulge into the anal canal and eventually prolapse, and the blood vessels within them lose their support and become distended.7PubMed. The pathogenesis of hemorrhoids This process becomes observable starting around the third decade of life, with significant individual variation in how fast it progresses.
This age-related weakening is why some people develop hemorrhoids even without obvious behavioral risk factors. You can eat a perfect diet, never strain, and keep bathroom visits short, but if the connective tissue supporting your anal cushions degrades early or quickly, you may still end up with symptoms. The aging component also explains why recurrence is common after treatment: if the underlying tissue support is gone, the cushions can slip out of position again under relatively mild provocation.
Exercise and Physical Exertion
Not all exercise contributes equally to hemorrhoid risk. A study surveying athletes across multiple sports found that certain activities carried notably higher rates of hemorrhoidal disease. Among those who practiced cycling or horseback riding, 57 percent reported suffering from hemorrhoids. Among bodybuilders, the figure was 48 percent. In a multivariate analysis adjusting for age and other factors, bodybuilding showed a statistically significant association with hemorrhoidal disease.8PubMed Central. Sport practice and hemorrhoidal disease: results from a self-assessment questionnaire among athletes
The mechanism differs by sport. Cycling and horseback riding involve sustained perineal pressure from sitting on a narrow saddle, which compresses the anal area directly. Bodybuilding, especially exercises like squats and deadlifts, generates massive intra-abdominal pressure during heavy lifts, similar in effect to straining at stool. Lifters who hold their breath and bear down (the Valsalva maneuver) spike that pressure further. If you lift heavy and notice hemorrhoid flares, exhaling during the effort phase and using a lifting belt to redistribute pressure may help, though the evidence for those specific modifications is more clinical wisdom than controlled trial.
Aerobic exercise like walking, swimming, and moderate jogging does not appear to carry the same risk and may actually help by improving bowel regularity and reducing the constipation that contributes to hemorrhoids in the first place.
Genetics and Family History
Some people seem to develop hemorrhoids no matter what they do, while others with worse habits never have a problem. Genetics appears to be part of the explanation. A recent review examining the molecular basis of hemorrhoidal disease identified several genes that may predispose people to the condition. Genes associated with varicose veins, chronic inflammation, and connective tissue alterations have all been implicated.9PubMed Central. How Can Molecules Induce Hemorrhoids? The Role of Genetics and Epigenetics in Hemorrhoidal Disease
If your parents or siblings have dealt with hemorrhoids, your connective tissue may be inherently weaker or your vascular tone less robust. This genetic susceptibility sets a lower threshold for the mechanical and behavioral triggers described earlier. You might develop hemorrhoids from a degree of straining or toilet sitting that would be harmless for someone with stronger tissue. This is a relatively young area of research, and there is no genetic test for hemorrhoid risk, but the hereditary component helps explain why the condition runs in families beyond just shared diet and bathroom habits.
The Gut Microbiome Connection
An emerging line of research is exploring whether changes in the gut microbiome contribute to hemorrhoid development. The idea is that an imbalanced microbial community in the lower gut could promote chronic low-grade inflammation in the anorectal area, weakening the tissue and making the cushions more vulnerable. Early evidence suggests that this kind of dysbiosis could be a driver of mucosal inflammation in the anorectal district and may contribute to hemorrhoids and other anorectal disorders.10PubMed Central. Altered Gut Microbic Flora and Haemorrhoids: Could They Have a Possible Relationship?
This research is still in early stages, and nobody is prescribing specific probiotics for hemorrhoid prevention yet. But it fits into a broader picture: the health of your intestinal lining and the balance of bacteria in your gut can affect inflammation throughout the digestive tract, including the very end of it. It also raises the possibility that antibiotic use, which disrupts the microbiome, could be an indirect contributor, though that connection remains speculative.
Does Toilet Posture Matter?
The modern sit-down toilet puts your body in a position that is not ideal for defecation. When sitting normally, the angle between the rectum and the anal canal is roughly 100 degrees, meaning the passage is partially kinked. Squatting straightens this angle to about 126 degrees, creating a more direct path for stool and reducing the effort required to pass it.11PubMed. Influence of Body Position on Defecation in Humans Less effort means less straining, which means less pressure on the hemorrhoidal cushions.
This is the rationale behind toilet footstools that elevate your knees above your hips while sitting. They approximate a squat position and can make bowel movements easier for some people. Populations that traditionally squat to defecate do appear to have lower rates of hemorrhoids, though that observation is confounded by differences in diet, physical activity, and other lifestyle factors. Still, if you already have hemorrhoids or are prone to them, raising your feet on a stool during bowel movements is a low-risk modification that addresses the biomechanics of the problem.
When It Might Not Be Hemorrhoids
One of the risks of hemorrhoids being so well-known is that people (and sometimes clinicians) blame them for symptoms that actually have a different cause. Several other anorectal conditions produce overlapping symptoms like bleeding, pain, and itching. Anal fissures, which are small tears in the lining of the anal canal, often cause sharp pain during bowel movements and bright red bleeding that looks identical to hemorrhoid bleeding. Pruritus ani, or chronic anal itching, can be caused by hemorrhoids but also by skin conditions, infections, and dietary irritants. More seriously, rectal bleeding can occasionally signal colorectal cancer or precancerous polyps.12PubMed Central. Common anorectal disorders
A condition worth knowing about is rectal varices, which look similar to hemorrhoids but are caused by a completely different mechanism. Rectal varices are dilated veins that form as a result of increased portal pressure, usually from liver disease. They make up fewer than 5 percent of variceal bleeding cases in Western countries, but the distinction matters because treating them like hemorrhoids can miss a serious underlying condition.13PubMed Central. Rectal varices vs hemorrhoids-diagnosis and management If you have known liver disease and develop what looks like hemorrhoids, your doctor should evaluate for varices specifically.
The general rule: any new rectal bleeding deserves at least a conversation with a clinician, even if you have a long history of hemorrhoids. Self-diagnosing rectal symptoms is one of the areas where being wrong carries the highest cost.
A Brief History of Hemorrhoid Treatment
Hemorrhoids have been documented in medical texts for thousands of years, and the treatment approaches have evolved dramatically. Ancient Egyptian papyri describe anorectal remedies, and Hippocrates wrote about hemorrhoid treatment in the fourth century BCE. For most of medical history, surgery was the primary option for significant hemorrhoids, and the procedures were often brutal by modern standards. The field has gone through numerous shifts in technique and philosophy, from early cauterization and ligation methods to the development of formal surgical excision in the twentieth century and the more recent move toward minimally invasive office-based procedures like rubber band ligation and infrared coagulation.14PubMed Central. Evolution of Surgical Management of Hemorrhoidal Disease: An Historical Overview
What is striking about this history is how long hemorrhoids were treated purely as a surgical problem. The idea that conservative management, including dietary changes, stool softeners, and topical treatments, could handle even moderate cases is relatively recent. Today, most gastroenterologists and colorectal surgeons recommend exhausting conservative options before considering procedures, and the trend is toward less invasive interventions when procedures are needed. The ancient Egyptians would probably have appreciated having a fiber supplement available before someone came at them with a hot iron.