REF-1268 · Awad et al., 2018 · Journal of Urology · Paper · PubMed

Does cycling harm my erections or bladder?

In 3,932 men, cyclists scored no worse than swimmers and runners on SHIM, I-PSS and NIH-CPSI; standing more and a higher bar went with less numbness. A survey.

Main caveat: Cross-sectional: associations, not causes; set-up and behaviour were reported at one time point alongside the symptoms.
moderate evidenceMeasured on recreational to trained athletes

Awad and colleagues (UCSF urology, with Washington University, Stanford and Dell Medical School) recruited cyclists through Facebook advertisements and outreach to sporting clubs in several countries, and swimmers and runners as a comparison group, to an online survey of validated questionnaires: the Sexual Health Inventory for Men (SHIM), the International Prostate Symptom Score (I-PSS) and the NIH Chronic Prostatitis Symptom Index (NIH-CPSI), plus questions on urinary tract infections, urethral stricture, genital numbness and saddle sores.

Cyclists were grouped as low or high intensity. Of 5,488 complete responses, 3,932 (72%) were analysed. On multivariable analysis the swimmers and runners had a lower mean SHIM score than low- and high-intensity cyclists (19.5 vs 19.9 and 20.7; p = 0.02 and < 0.001); I-PSS, NIH-CPSI and history of urinary tract infection did not differ.

Cyclists had higher odds of reporting a urethral stricture (OR 2.5, p = 0.042). Standing more than 20% of the time while cycling went with lower odds of genital numbness (OR 0.4, p = 0.006), and a handlebar adjusted level with or above the saddle with lower odds of genital numbness (OR 0.8, p = 0.005) and saddle sores (OR 0.6, p < 0.001).

The authors conclude that cyclists had no worse sexual or urinary function than swimmers or runners but were more prone to urethral stricture.

Our reading: the largest validated-instrument comparison the base holds for men; it supports "not worse" rather than "better" (the SHIM differences are under 1.5 points and the sample selected itself), and its useful content for a rider is the two modifiable set-up associations with numbness and sores, which agree in direction with the laboratory work on standing (REF-1270) and on bar height in women (REF-1272).

A pooled analysis that adjusted for age and comorbidities points the other way on erectile dysfunction (REF-1271).

Protocol

Design: multinational, multicenter cross-sectional survey (abstract; PubMed: Multicenter Study). The countries are not named in the men's abstract (the women's arm of the same survey names five English-speaking countries, REF-1269).
Recruitment: cyclists through Facebook advertisements and outreach to sporting clubs; swimmers and runners recruited as a comparison group (abstract).
Sample: 5,488 complete survey responses; n = 3932 (72%) included in the analysis; the reasons for excluding 28% are not given in the abstract. The split is 2,774 cyclists and 1,158 non-cyclists as the systematic review REF-1270 describes this survey (its full text; not stated in this abstract).
Groups: low-intensity cyclists, high-intensity cyclists, swimmers/runners; the intensity definition is not given in the abstract.
Outcomes: SHIM (higher scores mean better erectile function; erectile dysfunction is commonly defined as SHIM ≤ 21, the cut-off used in REF-1271); I-PSS (lower urinary tract symptoms); NIH-CPSI (pelvic pain and prostatitis-type symptoms); questions on urinary tract infections, urethral stricture, genital numbness and saddle sores (validation of these items not stated in the abstract). All self-reported.
Analysis: multivariable models; covariates and reference categories are not given in the abstract.
Affiliations, funding and interests: Department of Urology, University of California San Francisco (most authors; Awad also King Abdulaziz University, Rabigh); Washington University, St Louis; Stanford University; Dell Medical School, University of Texas (PubMed record).No funding is deposited in the Crossref or PubMed records and no conflict-of-interest statement is in the PubMed record; the paper's own statements could not be read. No saddle or bicycle company appears among the affiliations. An editorial comment was published with the paper (Yang H, Seftel AD, J Urol 199(3):804; not read).

Key Results

Outcome (multivariable analysis)Swimmers/runnersLow-intensity cyclistsHigh-intensity cyclists
SHIM, mean score19.519.9 (p = 0.02 vs swimmers/runners)20.7 (p < 0.001 vs swimmers/runners)
I-PSSno significant differenceno significant differenceno significant difference
NIH-CPSIno significant differenceno significant differenceno significant difference
History of urinary tract infectionno significant differenceno significant differenceno significant difference
Urethral stricturereferencecyclists: OR 2.5 (p = 0.042)
Factor while cyclingOutcomeORp
Standing more than 20% of the timegenital numbness0.40.006
Handlebar higher than or even with the saddlegenital numbness0.80.005
Handlebar higher than or even with the saddlesaddle sores0.6< 0.001
Not in the abstract: confidence intervals; the proportions with erectile dysfunction, numbness, sores or stricture; the covariates; the reference categories (the comparison for standing is presumably 20% or less of the time, and for the bar a bar below the saddle).
Size of the SHIM differences: 0.4 and 1.2 points between groups; the result says the groups were alike, not that cycling improves erectile function; the abstract gives no proportion of men in any group with a SHIM score of 21 or less.
Rare outcome: an OR of 2.5 for urethral stricture gives no absolute risk; how many men reported a stricture, and how it was diagnosed, are not in the abstract.

Mechanisms

Measured: no difference in validated urinary or pelvic-symptom scores and slightly higher SHIM scores in cyclists; lower odds of genital numbness with more standing and with a higher bar, and of saddle sores with a higher bar.
Authors' interpretation: increased time standing while cycling and a higher handlebar were associated with lower odds of genital sores and numbness — presented as modifiable factors.
Inference: standing takes the perineum off the saddle, and in laboratory studies of healthy men standing reversed the fall in penile oxygen pressure seen when seated (REF-1270); a bar level with the saddle moves weight back toward the sit bones, and in 41 competitive women a bar below the saddle went with higher perineal pressure (REF-1272). The survey measured neither pressure nor blood flow.
Inference: in a cross-sectional survey the arrows can run both ways — a rider with numbness may already have raised the bar or learned to stand — and riders who stand more may differ in discipline or terrain.

Practical Application

Does cycling harm my erections or bladder? In 3,932 men, cyclists scored no worse than swimmers and runners on SHIM, I-PSS and NIH-CPSI; standing more and a higher bar went with less numbness. A survey.
Numbness is the symptom to act on: among cyclists, standing more than 20% of the time went with lower odds of genital numbness (OR 0.4), and a bar level with or above the saddle with lower odds of numbness (OR 0.8) and saddle sores (OR 0.6) (B+, cross-sectional, from the abstract). Not from this paper; the base's own practice: both are low-cost changes to try.The survey does not show that making them relieves numbness, and in the women's arm of the same survey neither reached significance for numbness (REF-1269, full text, Table 5).
See a clinician. Not from this paper; the base's own practice: genital numbness that lasts after the ride or keeps returning, a change in erections, pain, or a change in the urinary stream goes to a clinician (urology or sports medicine); the assistant does not diagnose.
Say what the survey cannot show: that cycling protects erectile function (men with problems may have stopped riding or not answered), or that it is harmless for every rider — a pooled analysis found higher odds of erectile dysfunction in cyclists after adjustment for age and comorbidities (REF-1271, from its abstract).

Limitations

Cross-sectional: associations, not causes; set-up and behaviour were reported at one time point alongside the symptoms.
Selection: recruited through Facebook advertisements and sporting clubs — a self-selected sample; men with sexual or urinary problems may have stopped cycling or declined to take part, and swimmers and runners are active men, not a general-population comparison. 28% of complete responses were excluded for reasons not given in the abstract.
Self-report throughout; the items on numbness, sores, stricture and infections are not described as validated.
Small differences reach significance in a sample of this size; the SHIM gaps are under 1.5 points.
Abstract only: no confidence intervals, covariates, intensity definition, prevalences or discipline split could be checked.
Funding and conflicts: not available in the Crossref or PubMed records; the paper's own statements were not read.
How this entry was checked and changed
Why this level

(from the abstract) — the rubric's B+ row for a cross-sectional study with 100 or more (n = 3932), with validated instruments for the main outcomes (SHIM, I-PSS, NIH-CPSI). Held there, not higher, because it shows associations only, the sample selected itself through social media and clubs, every outcome is self-reported, and the abstract gives no confidence intervals, no covariates and no definition of cycling intensity. The full text was not read: the eScholarship PDF that OpenAlex lists for this DOI (item 1jw5b72p) downloads but contains a different article (Hampson et al., renal trauma, Urology), and the publisher version is not open