Occupational Physical Activity Is Negatively Associated With Semen Quality

BACKGROUND: Lifestyle factors have been associated with semen quality and have been implicated in the reported global decline in semen parameters. Moderate physical activity has been linked to improved semen quality; however, the association between occupational physical activity and semen quality is limited. OBJECTIVE: To study the association between male occupational physical activity and semen quality parameters. METHODS: A cross-sectional single-center study, with final study cohort of 280 males (after applying inclusion and exclusion criteria on n = 593) attending routine semen analysis at sperm laboratory, was subject to WHO criteria semen quality analysis (semen volume, sperm concentration, total sperm count, percentage sperm motility/morphology) and self-filled validated physical activity, lifestyle, and demographic questionnaires. Statistical analyses were done using SPSS Statistics (version 23). RESULTS: All occupational physical activity characteristics, except for sitting, were significantly associated with semen parameters. Sweating at work and physical tiredness were significantly and negatively associated with multiple semen parameters. Specifically, sweating at work was negatively associated with sperm concentration, morphology, and motility (Spearman r = -0.14 to -0.18, all p < 0.05). Physical tiredness at work was negatively associated with total sperm count, sperm concentration, morphology, and motility (Spearman r = -0.15 to -0.26, all p < 0.05). In hierarchical multiple regression analyses controlling for potential confounders, occupational physical activity expressed as physical tiredness independently predicted lower sperm concentration and morphology (β = -0.17 and -0.29, respectively; p < 0.01). DISCUSSION: Occupational physical activities are negatively associated with semen quality parameters, suggesting a potential adverse effect of work-related physical exertion on male reproductive function. CONCLUSIONS: The negative association between occupational physical activity characteristics and semen quality parameters highlights the importance of considering work-related physical exertion in the context of male fertility assessment, once evidence-based thresholds and standardized assessment protocols are established.