What Causes Hemorrhoids in Adults?
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| What Causes Hemorrhoids in Adults? |
Last Updated: June 2026 | Medically Reviewed | Based on Clinical Research
Most people don't think about hemorrhoids until they have them. And then, suddenly, they think about almost nothing else. The pain, the discomfort, the embarrassment of searching for answers in private — it all arrives at once, along with a question that should have been answered long before things got to this point.
What actually caused this?
It's a more important question than it might seem. Understanding what causes hemorrhoids is not just an exercise in medical curiosity.
It is the foundation of every decision you make about treatment, prevention, and whether you will be dealing with this same problem again in six months.
People who understand the causes of their hemorrhoids are the ones who manage to stay ahead of them.
People who don't tend to treat each flare-up as a mystery — something that just happens to them, unpredictably, with no clear reason and no clear path to prevention.
This article changes that.
What Hemorrhoids Actually Are
Before causes can make sense, the condition itself needs to be understood clearly — and most people have a slightly wrong picture of it.
Hemorrhoids are not some foreign growth that appears inside your body. They are not an infection, a tumor, or a disease in the traditional sense.
Hemorrhoids are veins — normal veins that exist in every human body, located in the tissue of the rectum and the area around the anus. These veins are part of a network called the hemorrhoidal plexus, and they serve a real biological function: they help control bowel movements and maintain continence.
Every person reading this article has hemorrhoidal tissue. Not every person suffers from hemorrhoids. The difference between normal hemorrhoidal tissue and a hemorrhoid that causes pain and bleeding lies in what has happened to that tissue over time — how much pressure it has been subjected to, how consistently it has been inflamed, and whether the supporting structures around it have been weakened to the point where the veins can no longer stay in their proper position.
Hemorrhoids become a problem when the veins swell, when the surrounding tissue weakens, and when the condition becomes chronic enough to cause symptoms that affect daily life.
The Primary Causes in Adults
Straining During Bowel Movements
If there is one cause that sits above all others in terms of how directly and consistently it contributes to hemorrhoids in adults, it is straining during bowel movements.
Every time you strain — every time you bear down hard, hold your breath, and push against resistance during a bowel movement — you create a sudden, significant spike in the pressure inside your abdominal cavity.
That pressure doesn't stay in the abdomen.
It travels downward, into the pelvic region, and directly into the network of veins surrounding the rectum.
Do that once, and the veins handle it. They are designed to handle occasional pressure spikes. But do it repeatedly, day after day, week after week, year after year — and those veins begin to stretch.
The walls weaken. The tissue surrounding them loses its elasticity.
The veins that once returned to their normal size after each bowel movement start to stay swollen. That persistent swelling is the hemorrhoid.
The reason straining happens is almost always constipation — stools that are too hard and too dry to pass without effort. And the reason constipation happens is almost always dietary. Which brings us to the next cause.
Chronic Constipation
Constipation and hemorrhoids are so closely linked that in many cases it is impossible to discuss one without the other. Constipation is both a primary cause of hemorrhoids and one of the main reasons they fail to heal and keep coming back.
When stools are hard and dry, they require force to pass. Force means straining. Straining means pressure on the rectal veins.
And beyond the straining itself, hard stools passing through the anal canal cause direct mechanical trauma to already inflamed and sensitive tissue — dragging across it, causing small tears, triggering bleeding, and resetting the inflammation cycle back to zero just as healing was beginning.
In adults, chronic constipation is most commonly caused by a diet low in fiber, inadequate fluid intake, a sedentary lifestyle, certain medications — particularly iron supplements, some pain medications, and certain antidepressants — and the habitual suppression of the urge to have a bowel movement, which allows stool to become harder and drier the longer it sits in the colon.
A Low-Fiber Diet
Diet deserves its own mention beyond constipation because its impact on hemorrhoid development goes further than simply causing hard stools.
Fiber does two things that are directly relevant to hemorrhoid prevention. Soluble fiber — found in oats, legumes, apples, and pears — absorbs water and forms a soft gel that keeps stools moist and easy to pass. Insoluble fiber — found in whole grains, vegetables, and bran — adds bulk to the stool and keeps it moving through the digestive system at a healthy pace, preventing the prolonged transit time that allows stools to dry out and harden.
Adults in most Western countries consume significantly less fiber than recommended. The recommended daily intake is around 25 to 38 grams, depending on age and sex. The average adult consumes somewhere between 10 and 15 grams per day — less than half of what their digestive system needs to function well.
This chronic fiber deficiency is one of the most significant reasons hemorrhoids are so common in adults in developed countries, and one of the most straightforward things to change.
Dehydration and Insufficient Fluid Intake
Water is as important to bowel health as fiber — and the two work together in a way that makes the absence of either one significantly worsen the effect of the other.
Fiber needs water to do its job. Without adequate fluid intake, soluble fiber cannot form the soft, water-absorbing gel that keeps stools moist. Instead, it bulks the stool up without softening it — potentially making constipation worse rather than better.
When the body is chronically underhydrated, the colon compensates by absorbing more water from the stool that passes through it — leaving behind stools that are harder, drier, and more difficult to pass than they would otherwise be.
Most adults do not drink enough water. Coffee, tea, sodas, and energy drinks are not substitutes — many of them are diuretics that increase fluid loss rather than replacing it. Plain water, consumed consistently throughout the day, is what keeps stools soft and the digestive system functioning the way it needs to.
Prolonged Sitting — On the Toilet and Off It
The relationship between sitting and hemorrhoids operates through two distinct mechanisms, and both matter.
The first is sitting on the toilet for extended periods. When you sit on a toilet seat, the ring-shaped opening creates an unsupported area directly beneath the rectal region. The veins in that area have no counter-pressure — they are essentially hanging freely, subjected to the full downward pull of gravity and the pressure from above. Sitting in this position for more than a few minutes at a time, particularly while straining or waiting, puts sustained, direct pressure on the hemorrhoidal veins in a way that no other sitting position does.
The habit of bringing a phone or a book into the bathroom and spending ten, fifteen, or twenty minutes on the toilet is one of the most reliably damaging things a person can do for their long-term hemorrhoid health. The urge to have a bowel movement should be acted on promptly — not prolonged.
The second mechanism is prolonged sitting in general. People who spend eight, nine, or ten hours a day sitting at a desk, in a car, or on a sofa are creating sustained, unrelenting pressure on the pelvic veins. Blood pools in the lower body, circulation in the pelvic region slows, and the hemorrhoidal veins are subjected to hours of continuous low-grade pressure that, over months and years, contributes meaningfully to their deterioration.
A Sedentary Lifestyle
Connected to prolonged sitting but broader than it — physical inactivity is a significant and often underappreciated contributor to hemorrhoid development in adults.
Regular physical activity stimulates bowel motility, the rhythmic muscular contractions that move stool through the digestive system.
People who exercise regularly tend to have more frequent, more regular, and easier bowel movements than those who are sedentary.
They also have better overall circulation, including in the pelvic region, which reduces the venous congestion that contributes to hemorrhoid formation.
You do not need to run marathons or lift heavy weights. A thirty-minute walk each day is enough to meaningfully improve bowel regularity and reduce the pelvic congestion that feeds hemorrhoid development. The problem is not that adults don't know exercise is good for them — it's that the connection between inactivity and hemorrhoids is rarely made explicit, leaving many people unaware that sitting less and moving more is one of the most direct preventive measures available to them.
Heavy Lifting
When you lift something heavy, your body automatically performs what physiologists call the Valsalva maneuver — you hold your breath, brace your core, and bear down to stabilize your trunk and generate force.
This maneuver creates a rapid, significant increase in intra-abdominal pressure. That pressure is transmitted directly downward into the pelvic floor and the hemorrhoidal veins.
A single heavy lift under controlled conditions is unlikely to cause hemorrhoids in an otherwise healthy person.
But repeated heavy lifting — particularly with poor breathing technique, excessive weight, or an existing dietary and hydration situation that already has the rectal veins under stress — compounds the pressure load in a way that meaningfully contributes to hemorrhoid development over time.
This is particularly relevant for adults in physically demanding occupations — construction, warehouse work, nursing, farming — where heavy lifting is not a choice but a daily occupational reality repeated dozens or hundreds of times per shift.
Pregnancy
Pregnancy is one of the most concentrated and unavoidable sets of hemorrhoid risk factors that exists. It deserves its own place in this list even though it applies only to women, because the mechanisms involved illustrate so clearly how multiple causes operating simultaneously produce such consistent results.
The growing uterus puts direct mechanical pressure on the pelvic veins, slowing blood flow and causing it to pool in the lower body.
The hormone progesterone relaxes the walls of the veins, making them more prone to swelling, while simultaneously slowing digestion and making constipation significantly more likely.
The increased blood volume of pregnancy — around fifty percent more blood than usual — raises the pressure inside blood vessels throughout the body, including those in the rectal region.
And then labor itself — the intense, sustained pushing of childbirth — delivers an enormous pressure event to the pelvic veins in a concentrated period of time, often triggering hemorrhoids that had not been present throughout the entire pregnancy.
Age and Tissue Weakness
As adults age, the connective tissue and supporting structures in the anal and rectal region gradually weaken. The tissue that holds the hemorrhoidal veins in position loses its elasticity.
Veins that might have returned to their normal size after a pressure event in a younger person stay swollen in an older one because the structural support that should pull them back is no longer as strong.
This is why hemorrhoids become significantly more common with age. It is not that older adults suddenly develop worse dietary habits or strain more than they did when they were younger — though those factors may also apply.
It is that the tissue itself becomes less resilient over time, and the same pressure events that were manageable in younger years begin to cause lasting damage in older ones.
Most adults who develop hemorrhoids for the first time after the age of forty are experiencing the combination of years of accumulated sub-optimal habits finally meeting tissue that is no longer able to absorb the impact without consequences.
Chronic Diarrhea
While constipation gets most of the attention in discussions of hemorrhoid causes, chronic diarrhea is an equally significant and often overlooked contributor.
Frequent loose stools increase the number of times per day that stool passes through the anal canal, multiplying the mechanical irritation of that tissue.
The urgency and speed of diarrheal stools can involve straining of a different kind — the effort to reach the bathroom in time, and the cramping and pressure of frequent bowel urgency.
The moisture and acidity of frequent loose stools irritates the delicate skin around the anus. And the frequency of wiping that accompanies diarrhea causes direct mechanical trauma to tissue that is already sensitized and irritated.
Adults with irritable bowel syndrome, inflammatory bowel disease, food intolerances, or other conditions that cause chronic loose stools are at significantly elevated risk of hemorrhoid development for these reasons.
Obesity
Excess body weight creates sustained, elevated intra-abdominal pressure. A larger abdomen pressing downward on the pelvic floor means more constant pressure on the hemorrhoidal veins — not just during straining or lifting, but continuously, throughout every hour of every day.
Obesity is also associated with higher rates of sedentary behavior, poor dietary habits, and chronic constipation — each of which independently contributes to hemorrhoid development.
The combination of all of these factors makes obesity one of the most significant risk multipliers for hemorrhoids in adults, even though it is rarely discussed explicitly in that context.
Genetics
Not every adult who develops hemorrhoids has obvious lifestyle risk factors. Some people develop hemorrhoids despite eating well, staying hydrated, exercising regularly, and using correct technique when lifting. For these individuals, genetics is often the underlying explanation.
Some people are simply born with vein walls that are more prone to weakness and distension than others — in the same way that some families have a history of varicose veins in the legs.
The hemorrhoidal veins in these individuals are structurally more likely to swell and stay swollen under conditions that would not cause problems for someone without that genetic predisposition.
Genetics does not make hemorrhoids inevitable. It makes them more likely under the right conditions — which makes the preventive habits more important for these individuals, not less.
Why Adults Are Particularly Vulnerable
Children rarely develop hemorrhoids. Teenagers rarely develop hemorrhoids. The condition becomes dramatically more common in adults — and more common still as adults age. This pattern reflects the cumulative nature of the damage involved.
Hemorrhoids in adults are almost never the result of a single event or a single cause. They are the result of years of accumulated pressure, dietary habits that gradually wore down the health of the digestive system, hours of sitting that slowly reduced circulation in the pelvic region, and tissue that was never given adequate time or conditions to fully recover between insults.
This is both the sobering and the hopeful truth about what causes hemorrhoids in adults. Sobering, because it means the problem was building for longer than most people realize.
Hopeful, because it means that the same cumulative logic that caused the problem can, with consistent changes in the right direction, gradually reverse it — or at the very least, stop it from getting worse.
Conclusion
Hemorrhoids in adults are rarely the result of bad luck. They are almost always the result of a combination of factors — dietary, behavioral, physical, and sometimes genetic — that have been operating quietly in the background for months or years before the first painful symptom makes itself known.
Understanding those factors is not about blame. It is about clarity. When you know what caused the problem, you know what needs to change. And when you know what needs to change, you have something far more valuable than a cream or a remedy or a temporary fix.
You have a path forward.
The causes listed in this article are not abstract medical concepts. They are things that happen in real daily life — at the dinner table, in the bathroom, at the desk, in the gym. They are things that can be understood, addressed, and changed.
Not perfectly, not overnight, and not without effort — but genuinely, meaningfully, and in ways that make a real difference to how often hemorrhoids disrupt your life and how severely they do so when they come back.
That is worth understanding. And now you do.
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📚 Medical sources
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Fiber intake and hemorrhoid prevention Alonso-Coello, P., et al. (2006). Fiber for the treatment of hemorrhoids complications: a systematic review and meta-analysis. American Journal of Gastroenterology, 101(1), 181–188.
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