Physical Activity and Sedentary Time in Relation to Semen Quality in Healthy Men Screened as Potential Sperm Donors

Bin Sun; Carmen Messerlian; Zhong-Han Sun; Peng Duan; Heng-Gui Chen; Ying-Jun Chen; Peng Wang; Liang Wang; Tian-Qing Meng; Qi Wang; Mariel Arvizu; Jorge E. Chavarro; Yi-Xin Wang; Cheng-Liang Xiong; An Pan

Disclosures

Hum Reprod. 2019;34(12):2330-2339. 

In This Article

Abstract and Introduction

Abstract

Study Question: Is physical activity or sedentary time associated with semen quality parameters?

Summary Answer: Among healthy men screened as potential sperm donors, higher self-reported physical activity was associated with increased progressive and total sperm motility.

What is Known Already: Despite 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, Duration: Healthy 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, Methods: Total 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 Chance: After 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 Caution: The 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 Findings: Our 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.

Introduction

Moderate physical activity is widely recognized as an important component of a healthy lifestyle, which has been associated with reduced risks of diabetes (Aune et al., 2015), cardiovascular diseases (Lee, 2010), certain cancers (Rezende et al., 2018) and depression (Mammen and Faulkner, 2013), potentially by reducing endogenous oxidative stress and changing endogenous sexual hormone secretion. The World Health Organization (WHO) has ranked physical inactivity as the fourth leading risk factor of global mortality (WHO 2010a). However, whether moderate physical activity has any beneficial effect on male fertility remains inconclusive.

Several epidemiologic studies have revealed a positive association between physical activity and sperm concentration, progressive motility and percent of normal morphology (Vaamonde et al., 2012; Li et al., 2013; Gaskins et al., 2014). In contrast, Gebreegziabher et al. (2004) found that distance cyclists had a significantly higher percentage of abnormal spermatozoa than the controls; an early intervention study conducted among five normal human volunteers reported reduced total sperm count and serum testosterone levels after a 3-month overtraining (Roberts et al., 1993). Meanwhile, a lack of convincing association between physical activity and markers of semen quality was also reported (Minguez-Alarcon et al., 2014; Jozkow et al., 2017). The controversial findings may be due in part to imprecise risk estimation driven by limited sample size (mostly less than 100 men) and non-uniform measures to characterize individuals' physical activity patterns. More importantly, all previous studies collected semen samples at a single time point, which may have resulted in measurement error due to the high within-individual variability in semen quality parameters (Chiu et al., 2017).

In the present study, we recruited 746 healthy men screened as potential sperm donors who provided repeated semen samples (n = 5252) over an approximately 6-month period. We applied a validated long-form International Physical Activity Questionnaire (IPAQ) to determine participants' physical activity patterns and sedentary time and assessed associations with repeated measures of semen quality parameters.

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