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

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• For couples with male factor infertility, this review recommends moderate intensity-aerobic exercise in combination with strength training to be the intervention with the highest probability of being the best approach for reproductive health benefits.
• A conservative interpretation of the findings is required because they were based on single studies.

Introduction

The World Health Organisation estimates that infertility affects 10% to 15% of couples in industrialised countries. Approximately 50% of all infertility cases are attributed to male-related factors, in particular, poor semen quality (called male factor infertility). The aim of this study was to evaluate the effectiveness of exercise training on male factor infertility and seminal markers of inflammation.

Methods

This is the first study to undertake a systematic review with network meta-analysis of 7 RCTs to evaluate the effectiveness of 1 or more types of exercise interventions on male factor infertility and seminal markers of inflammation, as well as to provide clinicians with a ranking of treatments to inform them of the treatment effects of exercise training and physical activity.

The forms of exercise include: moderate-intensity continuous training (MICT), resistance training (RT), combined aerobic and resistance training (CET), high-intensity continuous training (HICT), and high-intensity interval training (HIIT).

7 RCTs representing 18 groups (11 exercise (supervised, not home-based), 7 non-intervention control [NON-EX]) and 2641 participants and/or patients (1429 exercise, 1212 NON-EX). All the RCTs were conducted in Iran involving healthy adult participants and/or infertile patients (with doctor-diagnosed male factor infertility). The intervention period was ≥10 weeks with a follow-up period. None of the studies reported changes in either patients’ dietary intakes or normal daily physical activities and lifestyles during the intervention period.

Results

Compared with a non-intervention control group, the top ranking interventions:

For pregnancy rate: Combined aerobic and resistance training (CET) (p= 0.89 relative risk [RR] = 27.81), moderate-intensity continuous training (MICT) (p=0.87, RR = 26.67), resistance training (RT) (p=0.61,RR = 12.54), high intensity continuous training (HICT) (p=0.34, RR = 5.55), and high-intensity interval training (HIIT) (p=0.28, RR = 4.63).

For live birth rate: MICT (p=0.82, RR = 10.05), RT (p=0.70, RR = 4.92), HIIT (p=0.66, RR = 4.38)), CET (p=0.45, RR = 2.20), and HICT (p=0.30, RR = 1.55)

The following parameters/markers rank the 5 exercise strategies in order of effectiveness:

• Semen quality parameters were significantly improved after the following types of exercise interventions as compared with the non-intervention group [NON-EX]: CET > MICT > HICT > RT > HIIT
• The following training strategies were significantly better at improving seminal markers of oxidative stress: CET > MICT > HIIT > HICT > RT
• The following training strategies were significantly better at improving seminal markers of inflammation: CET > MICT > HIIT > RT > HICT
• The following training strategies were significantly better at improving measures of body composition and VO2 max: CET > HICT > MICT > HIIT > RT
• There was insufficient evidence of a difference for the selected types of exercise interventions versus NON-EX group for pregnancy and live birth rates in healthy participants.

Conclusion

Combined aerobic and resistance training (CET) was found to be the intervention with the highest probability of being the best approach for improving the male factor infertility.

• In light of these findings, it is reasonable to propose that infertile men and at-risk populations take part in the top-ranking interventions identified in this analysis.
• For substantial reproductive health benefits, one should consider doing all of the selected types of exercise interventions (CET, MICT, RT, HICT, and HIIT); however, moderate intensity-aerobic exercise and strength training in combination would generally be more favourable to lend clinically significant improvements.
• To add to this, exercise can offer a myriad of other health benefits, is a possibly safe activity and a cost-effective treatment strategy for male factor infertility.

• There was only a small number of relevant trials available for comparison suggesting the need for additional study in this field.
• Further trials are needed to analyse the dose-response impacts of exercise modalities on male reproductive function.
• The results propose several domains for development in the reporting of RCTs addressing the impacts of interventional exercise studies on male reproductive function.
• Heterogeneity of some findings and discrepancy across the included studies was significant. For example, variations in the characteristics of training programs. Future analyses should aim to continue to address this.
• There is a concern that this study may not relate to already active patients with male factor infertility which future studies should address.