Physical activity and sedentary time in relation to semen quality in healthy men screened as potential sperm donors
Authors: Sun Bin , Messerlian Carmen , Sun Zhong-Han , Duan Peng , Chen Heng-Gui , Chen Ying-Jun , Wang Peng , Wang Liang , Meng Tian-Qing , Wang Qi , Arvizu Mariel , Chavarro Jorge E , Wang Yi-Xin , Xiong Cheng-Liang , Pan An 
Published: October 2019

AbstractSTUDY QUESTIONIs physical activity or sedentary time associated with semen quality parameters?SUMMARY ANSWERAmong healthy men screened as potential sperm donors, higher self-reported physical activity was associated with increased progressive and total sperm motility.WHAT IS KNOWN ALREADYDespite the claimed beneficial effect of moderate physical activity on semen quality, results from epidemiological studies have been inconclusive. Previous studies were mostly conducted among endurance athletes or male partners of couples who sought infertility treatment.STUDY DESIGN, SIZE, DURATIONHealthy men screened as potential sperm donors were recruited at the Hubei Province Human Sperm Bank of China. Between April 2017 and July 2018; 746 men completed the long-form International Physical Activity Questionnaire (IPAQ) and provided repeated semen samples (n = 5252) during an approximately 6-month period.PARTICIPANTS/MATERIALS, SETTING, METHODSTotal metabolic equivalents (METs), moderate-to-vigorous METs and sedentary time were abstracted from the IPAQ. Sperm concentration, total sperm count, progressive motility and total motility in repeated specimens were determined by trained clinical technicians. Mixed-effect models were applied to investigate the relationships between physical activity and sedentary time and repeated measures of semen quality parameters.MAIN RESULTS AND THE ROLE OF CHANCEAfter adjusting for multiple confounders, total METs and moderate-to-vigorous METs were both positively associated with progressive and total sperm motility. Compared with men in the lowest quartiles, those in the highest quartiles of total and moderate-to-vigorous METs had increased progressive motility of 16.1% (95% CI: 6.4, 26.8%) and 17.3% (95% CI: 7.5, 27.9%), respectively, and had increased total motility of 15.2% (95% CI: 6.2, 24.9%) and 16.4% (95% CI: 7.4, 26.1%), respectively. Sedentary time was not associated with semen quality parameters.LIMITATIONS, REASONS FOR CAUTIONThe IPAQ was reported only once from study participants; measurement errors were inevitable and may have biased our results. Furthermore, although we have adjusted for various potential confounders, the possibility of unmeasured confounding cannot be fully ruled out.WIDER IMPLICATIONS OF THE FINDINGSOur findings suggest that maintaining regular exercise may improve semen quality parameters among healthy, non-infertile men. Specifically, we found that higher self-reported total and moderate-to-vigorous METs were associated with improved sperm motility, which reinforces the existing evidence that physical activity may improve male reproductive health.STUDY FUNDING/COMPETING INTEREST(S)Y.-X.W was supported by the Initiative Postdocs Supporting Program (No. BX201700087). A.P. was supported by the National Key Research and Development Program of China (2017YFC0907504). C.-L.X. was supported by the National Key Research and Development Program of China (2016YFC1000206). The authors report no conflicts of interest.TRIAL REGISTRATION NUMBERN/A