Introduction

Erectile dysfunction (ED) is one of the most common sexual dysfunctions in biological males, affecting a significant population and usually increasing in prevalence with age. Previous studies have shown that physical activity can help with erectile function; aerobic exercises and activities can enhance vascular function, reduce inflammation, and improve blood flow, which all contribute to good erectile function. However, aerobic activities are not accessible for every individual and may be more difficult to do, especially as men age. Walking is accessible, simple, and free, making it a good exercise to incorporate into daily routines and potentially improve erectile function.

The aim of this study was to investigate the causal effects of walking on the risk of ED in men. Current research suggests walking may have a broader range of health impacts, one of which is potential improvements to male sexual function. Researchers used Mendelian Randomization (MR), which employs genetic variants as independent variables (IVs) to infer causal relationships between exposures (walking) and outcomes (risk of erectile dysfunction). They believe this study could lead to targeted recommendations for improving quality of life in men.

Methods

Instead of human subjects as IVs, researchers used single nucleotide polymorphisms (SNPs) - which are a variant in a DNA sequence - that were significantly associated with the walking phenotype and did not directly influence erectile dysfunction. They found these via a genome-wide association study (GWAS), a research method that analyzes DNA to identify genetic variants (SNPs). SNP data was received from a study conducted at the UK Biobank based on three questions answered via touchscreen questionnaire:

• “On how many days in a typical week do you walk at least 10 minutes once?” (measuring the frequency of walking of 454,783 subjects)
• “On a typical day, how many minutes do you spend walking? (If the walking time varies greatly on different days of the week, give the average walking time)” (measuring the self-reported duration of walks of 395,831 subjects)
• “How would you describe your usual walking pace?” (measuring self-reported usual walking pace of 459,915 subjects)

GWAS summary data (genetic data) came from a large meta-analysis study looking at DNA from individuals with either self or doctor-reported ED, use of ED medication, or a history of surgical intervention. This resulted in a remaining sample of 6,175 subjects with ED, and 217,630 non-ED control subjects, all European. SNPs (genetic variants) used for the final MR analysis were strongly associated with the exposure (walking), not correlated with other health risks (diabetes, obesity, smoking, depression, etc.), and were not significantly associated with ED across the GWAS data. The genetic walking variant (SNP) compared against the ED genetic data (GWAS) was then used for the final study.

Results

After this rigorous selection process, an MR analysis was conducted alongside several extensive sensitivity analyses to rule out inconsistencies, health risks, and outliers. Identified from these were 12 IVs for duration of walks, 45 IVs for pace of walks, and 16 IVs for frequency of walks (days per week). The univariable MR analysis showed no causal relationship between reduced risk of ED and duration or frequency of walking. However, results did show that an increase in usual walking pace is associated with a reduced risk. These results are supported by the multivariable MR analysis, which included SNPs associated with other health risk factors (diabetes, obesity, smoking, etc.).

Discussion & Conclusion

The results of these analyses suggest that increased walking pace is directly related to a reduced risk of erectile dysfunction. More accurately, a 1 mile-per-hour increase in walking pace is attributed to a 76% reduction in risk, supporting previous evidence further by providing genetic evidence.

There are a few limitations in this study, however. The GWAS data sets were exclusively from European populations, which may make results difficult to generalize for other ethnic groups. There may also be underlying issues not laid out in genetic data that interfere with results. Additionally, 10 minutes of walking may not be a good indicator of how frequently patients are walking. Future research would want to adjust and test for these limitations.

Brisk walking may enhance cardiovascular health by improving cardiorespiratory fitness, lowering blood pressure and cholesterol, therefore enhancing blood flow to the penile tissues and having more of a direct effect on ED. It may also help with anxiety and depression – which play a large role in the progression of ED in men – by helping to reduce stress, control weight, and balance hormones. Researchers think it may be beneficial to encourage men to maintain a walking pace of over 4 miles-per-hour as an effective way to reduce the incidence of erectile dysfunction.

References:

• Fang, Y., Chen, S., Huang, C., Deng, X., Lai, R., Lv, X., & Cheng, B. (2024). Increased walking pace reduces the rate of erectile dysfunction: Results from a multivariable Mendelian randomization study. The Journal of Sexual Medicine, 22(2), 298–306. https://doi.org/10.1093/jsxmed/qdae178