Constipation and Straining
Constipation and the straining it causes are the most classically recognized risk factors for hemorrhoids — and remain relevant even as newer research has added nuance about how much of the risk comes from straining itself versus other related factors, like time spent on the toilet.
- Straining directly increases pressure on the veins in the anal canal, which is the core mechanism behind hemorrhoid formation.
- Constipation contributes indirectly by making straining more likely and more forceful, since harder stool is more difficult to pass.
- Newer research suggests time spent on the toilet may matter independently of straining itself — see Sitting too long on the toilet.
- Addressing constipation at its source (fiber, fluids, movement) is more effective than treating hemorrhoid symptoms without addressing the underlying constipation.
Why straining matters mechanically
Straining during a bowel movement increases pressure within the abdomen and pelvis, which is transmitted directly to the veins in the anal canal. Repeated straining, especially over months or years, contributes to the engorgement and downward displacement of hemorrhoidal tissue described in Why do hemorrhoids happen?
How constipation feeds into this
Constipation — infrequent, hard, or difficult-to-pass stools — makes straining more likely and typically more forceful, since harder stool requires more effort to pass. Common contributors to constipation include:
- Inadequate fiber intake
- Inadequate fluid intake
- Low physical activity
- Certain medications (see Medications that contribute)
- Ignoring the urge to go, which can allow stool to become harder over time
What recent research adds to this picture
A 2025 study examining smartphone use on the toilet found that, in its statistical analysis, straining and constipation rates didn’t differ significantly between groups with and without hemorrhoids — while time spent on the toilet did. This doesn’t mean straining is irrelevant; it’s still one of the most consistently cited risk factors across the broader research base. But it does suggest that how long you’re on the toilet, independent of how hard you’re straining, is its own meaningful factor — worth addressing alongside, not instead of, straining itself. See Sitting too long on the toilet for more on this.
What actually helps
- Fiber, from food or a supplement if needed, to soften stool and reduce the force needed to pass it
- Adequate fluid intake, since fiber without enough fluid can worsen constipation rather than help it
- Responding promptly to the urge to go, rather than delaying, which can allow stool to harden further
- Regular physical activity, which supports normal bowel motility
- Limiting time on the toilet — going when you need to go, rather than sitting and waiting (or scrolling) for something to happen
When constipation itself needs attention
Occasional constipation is common and usually responds to the measures above. Persistent constipation — especially new constipation, or a change in your usual bowel pattern — is itself one of the red flag symptoms worth mentioning to a doctor, separate from any hemorrhoid symptoms it may be contributing to.
This page is for general education. Persistent or new constipation is worth discussing with a doctor, both for the constipation itself and for any hemorrhoid symptoms it may be contributing to.