Effectiveness of Exercise Training on Male Factor Infertility: A Systematic Review and Network Meta-analysis

Abstract

Context: Mounting evidence from the literature suggests that different types of training interventions can be successful at improving several aspects of male reproductive function in both fertile and infertile populations.

Objective: The aim of this study was to evaluate the effectiveness of exercise training on male factor infertility and seminal markers of inflammation.

Data sources: We searched PubMed, CISCOM, Springer, Elsevier Science, Cochrane Central Register of Controlled Trials, Scopus, PEDro, Ovid (Medline, EMBASE, PsycINFO), Sport Discus, Orbis, CINAHL, Web of Science, ProQuest, and the ClinicalTrials.gov registry for randomized controlled trials (RCTs) that analyzed the impacts of selected types of exercise interventions on markers of male reproductive function and reproductive performance.

Study selection: A total of 336 records were identified, of which we included 7 trials reporting on 2641 fertile and infertile men in the systematic review and network meta-analysis.

Level of evidence: Level 1 (because this is a systematic review of RCTs).

Data extraction: The data included the study design, participant characteristics, inclusion and exclusion, intervention characteristics, outcome measures, and the main results of the study.

Results: The results of network meta-analysis showed that, compared with a nonintervention control group, the top-ranking interventions for pregnancy rate were for combined aerobic and resistance training (CET) (relative risk [RR] = 27.81), moderate-intensity continuous training (MICT) (RR = 26.67), resistance training (RT) (RR = 12.54), high-intensity continuous training (HICT) (RR = 5.55), and high-intensity interval training (HIIT) (RR = 4.63). While the top-ranking interventions for live birth rate were for MICT (RR = 10.05), RT (RR = 4.92), HIIT (RR = 4.38), CET (RR = 2.20), and HICT (RR = 1.55). Also, with the following order of effectiveness, 5 training strategies were significantly better at improving semen quality parameters (CET > MICT > HICT > RT > HIIT), seminal markers of oxidative stress (CET > MICT > HIIT > HICT > RT), seminal markers of inflammation (CET > MICT > HIIT > RT > HICT), as well as measures of body composition and VO₂max (CET > HICT > MICT > HIIT > RT).

Conclusion: The review recommends that the intervention with the highest probability of being the best approach out of all available options for improving the male factor infertility was for CET.

Keywords: DNA fragmentation; exercise training; male factor infertility; network meta-analysis; spermatogenesis.

Figure 1.

PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) flow diagram of studies included in the network meta-analysis.

Figure 2.

Forest plot showing the results of the network meta-analysis for semen quality parameters. CET, combined aerobic and resistance exercise training; HICT, high-intensity continuous training protocol; HIIT, high-intensity interval training; MICT, moderate-intensity continuous training; NON-EX, nonintervention control; RT, resistance training, SMD, standardized mean difference.