- A 2026 study links insomnia, long sleep duration, and daytime napping to increased hemorrhoid risk via genetic analysis.
- Mendelian randomization confirms sleep issues independently raise hemorrhoid odds, not vice versa.
- Poor sleep disrupts digestion and causes inflammation, both tied to hemorrhoid development.
- Dietary fiber, hydration, and avoiding prolonged toilet time remain top prevention strategies.
- The study highlights free, lifestyle-based solutions over medical treatments for hemorrhoid prevention.
A study published in 2026 in the journal Neuropsychiatric Research has uncovered a surprising connection between sleep habits and hemorrhoids, the swollen anal veins that affect roughly half of adults by age 50. Researchers from Peking University People's Hospital in Beijing used genetic data covering more than 218,000 hemorrhoid cases and over 725,000 controls, drawn largely from people of European ancestry, and found that insomnia, longer sleep duration, and daytime napping each independently raised the odds of developing the condition. Notably, the reverse wasn't true: the analysis found no evidence that hemorrhoids themselves cause sleep problems, suggesting a one-way relationship.
Genetic method points to cause, not just correlation
The researchers used a technique called Mendelian randomization, which relies on naturally occurring genetic variants to infer cause-and-effect relationships rather than simply noting that two things tend to occur together. Cross-referencing data from the UK Biobank and Finland's FinnGen database, the team found that people genetically predisposed to insomnia faced roughly 23% higher odds of hemorrhoids, those with longer nightly sleep had about 16% higher odds, and daytime nappers saw a 14% increase. Researchers screened out genetic variants tied to body weight, smoking, and alcohol use to isolate sleep's specific role, and the findings held up even after stricter statistical correction was applied. Other sleep issues tested, including sleep apnea, showed no meaningful link to hemorrhoids.
Poor sleep may disrupt digestion and inflame blood vessels
The authors point to two likely mechanisms. Disrupted sleep, especially from insomnia, can throw off the body's circadian rhythm, slowing digestion and raising the risk of constipation — a well-established trigger for hemorrhoids, since straining during bowel movements puts direct pressure on rectal veins. Chronic poor sleep also appears to fuel body-wide inflammation, which can weaken blood vessel walls and promote the swelling at the core of hemorrhoidal disease.
As for napping, the researchers suspect it's tied to reduced daytime movement, which can impair circulation and increase pelvic pressure. Colorectal surgeons say the pattern lines up with what they see in practice: patients with ongoing sleep trouble often also struggle with constipation and hemorrhoids, giving a plausible clinical explanation to go along with the genetic data.
Fiber and hydration remain the front line of prevention
Sleep is only part of the picture. The American Gastroenterological Association's newer guidelines still identify dietary fiber as the top prevention tool, recommending 25 to 38 grams a day depending on age and sex — a target only about 5% of men and 9% of women currently hit. Drinking at least two liters of water daily and staying physically active also help prevent the constipation that leads to straining. Doctors interviewed by other outlets have also pointed to a more modern culprit: sitting on the toilet longer than five minutes, often while scrolling on a phone, which increases blood flow to the anus and adds pressure even without straining.
None of this requires a prescription. Better sleep, more fiber, more water, and less time parked on a smartphone in the bathroom cost nothing and carry no side effects. It's a good reminder that some of the most effective health interventions are still the free ones. Given how often chronic, everyday conditions like this get treated with creams, procedures, or pills before anyone asks about sleep or diet, this study is a useful nudge to look at the basics first.
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