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The Effect of Endurance Exercise on Semen Quality in Male Athletes: A Systematic Review



Endurance exercise has the potential to affect reproductive function, with amenorrhea in female athletes. However, most studies focus on women. Evidence on the association between endurance exercise and male fertility is limited.


To synthesise existing literature on exercise-induced alterations in semen parameters and to assess the clinical impact on male fertility.


Studies reporting on the association between semen parameters and endurance exercise in healthy men were eligible. Men attending fertility clinics were excluded. We searched MEDLINE (PubMed), Embase, SPORTDiscus, Cochrane Central Register of Controlled Trials (CENTRAL), and International Clinical Trials Registry Platform (ICTRP) from their inception to May 28th 2022. JBI Critical Appraisal Tool was used to assess the potential risk of bias.


Thirteen studies met inclusion criteria, reporting on 280 subjects. Eight articles reported on endurance runners, three on cyclists and four on triathletes. Four studies did not find any statistically significant sperm alterations. Five reported significant changes in semen parameters, but these were not clinically relevant, as semen parameters remained well above World Health Organisation (WHO) thresholds. Four articles reported a decrease in semen quality with potential clinical consequences as they found a reduced number of sperm cells exhibiting normal morphology in cyclists and triathletes and a greater amount of DNA fragmentation in triathletes.


Endurance exercise can have a negative effect on semen quality, although rarely with a clinically relevant impact on male fertility. Evidence is however limited, with poor quality of the included studies.

Registration: PROSPERO International prospective register of systematic reviews (CRD42022336753).

Key Points

  • Results suggest that endurance exercise can decrease semen quality, although without a clinically relevant impact on male fertility potential.

  • The available evidence is limited and lacks comparability due to poor methodology. High quality studies are necessary to further assess the relationship between endurance exercise and semen quality.


Practicing moderate physical activity on a regular basis is associated with multiple health benefits. There is strong evidence that exercise has a preventive effect on pathogenesis and also leads to better symptom control in various somatic and psychiatric disorders [1]. Nonetheless, prolonged exercise may induce a condition called “overtraining”, which can be harmful to numerous physiological pathways [2]. Research mainly focusses on female athletes because they present with clinically visible symptoms such as amenorrhea. Amenorrhea is a component of the “Female Athlete triad” together with low energy availability (LEA) and decreased bone mineral density [3, 4]. Unfavourable reproductive health consequences in male athletes are less studied due to the absence of clinical signs and symptoms, although there is ongoing interest in the effect of endurance exercise on semen quality [4, 5].

So far, the literature has been ambiguous whether exercise affects spermatogenesis or not. Several theories on a possible association have been formulated. First, since spermatogenesis depends on testicular testosterone production, many authors focus on exercise-induced hormonal changes in male athletes [6]. In 2014 “Relative Energy Deficiency in Sport” (REDs) was introduced [7]. This is a comprehensive term for the condition previously known as “Female Athlete Triad”, as it now also includes low testosterone and fertility problems in male athletes. LEA is the underlying cause of REDs and can be defined as a mismatch between energy intake and expenditure, thereby leaving insufficient energy for metabolic pathways and disrupting the normal function of the hypothalamic-pituitary–gonadal (HPG) axis [7]. LEA can lead to low gonadotropin concentrations, low testosterone and subsequent reproductive problems in male athletes [8]. Furthermore, there are other consequences of endurance exercise that can negatively influence spermatogenesis. The increase in body temperature and wearing tight clothing during exercise may elevate scrotal temperature leading to impaired spermatogenesis [9,10,11,12]. Moreover, strenuous exercise causes excessive formation of reactive oxygen species (ROS), which can affect sperm DNA [13,14,15,16,17]. Also, there are sport-specific factors, such as sitting on a bicycle seat leading to mechanical compression of the testis, epididymis and vas deferens. This may induce testicular microtrauma and reduce testicular blood flow [18] and impair the secretory function of the prostate gland, which normally enhances the motility of spermatozoa [19].

Spermatogenesis is a multifactorial process, lasting approximately 70 days, in which germ cells undergo mitotic cell division, meiosis and spermiogenesis to become mature spermatozoa [20, 21]. This process is hormonally controlled by the HPG axis. By secreting gonadotropin-releasing hormone (GnRH), the hypothalamus stimulates the pituitary gland to release gonadotropins. Follicle stimulating-hormone (FSH) stimulates Sertoli cells to support spermatogenesis. Luteinizing hormone (LH) activates Leydig cells to produce testosterone, which is necessary for normal spermatogenesis and maturation of spermatozoa [22]. Semen analysis is a delicate procedure [23]. It is crucial to process and analyse semen samples in a standardized way, with clear instructions about abstinence time [24, 25]. Moreover, to account for individual variability in semen parameters, two consecutive semen samples should be examined [26].

In this systematic review, we aim to provide a comprehensive synthesis of the existing literature investigating exercise-induced alterations in semen parameters.


We wrote this systematic review guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 checklist in order to report a transparent and complete review [27]. We registered the protocol for this systematic review before data extraction on PROSPERO International prospective register of systematic reviews (CRD42022336753). Our systematic review was approved by the KU Leuven ethics committee (MP018647).

Search Strategy

The literature search was conducted according to the PRISMA-S checklist [28]. A comprehensive search strategy was developed by two authors (AA and LA), assisted by a staff member of the 2Bergen library of the Biomedical Sciences Group at KU Leuven. Our search strings consisted of MeSH terms, Emtree terms, keywords and free text. We searched four databases: MEDLINE (PubMed), Embase, SPORTDiscus and Cochrane Central Register of Controlled Trials (CENTRAL). Additionally, we explored two registers: and International Clinical Trials Registry Platform (ICTRP). These sources were consulted from inception to May 28th 2022. For each platform, we modified the search string to implement database-specific filters and search terms. The complete search strategy is described in Supplementary Table S1.

Eligibility Criteria

There were no limitations regarding publication date. We limited our search to English, Dutch or French articles but only retrieved English records. Case reports, qualitative studies and animal studies were excluded.

Studies that reported on the relationship between semen characteristics and endurance exercise were eligible. The subjects were required to meet the following criteria: men without chronic illnesses or reproductive problems, and detailed reporting of practicing endurance exercise. Therefore, men attending fertility clinics were excluded to avoid bias secondary to disturbed baseline sperm characteristics. Interventions had to be expressed in quantitative numbers, for example training volume or metabolic equivalent of task (MET). Outcomes were defined as semen parameters (total sperm count, sperm concentration, motility, morphology, total motile sperm count, DNA fragmentation).

Selection Process

After performing the search, duplicates were manually removed in EndNote20. To avoid reporting bias, two authors (AA and TA) independently screened all articles for eligibility at title/abstract stage and at full-text stage, using the systemic review software application Rayyan. For titles and abstracts that seemed relevant, full texts were retrieved and evaluated against the inclusion and exclusion criteria. Furthermore, we screened the reference lists of retrieved studies to find other relevant reports. Discrepancies were resolved by discussion. The search process was presented by the PRISMA flow diagram, along with reasons for exclusion (Fig. 1).

Fig. 1
figure 1

PRISMA 2020 flow diagram of study selection

Data Collection Process, Synthesis Methods and Risk of Bias Assessment

The data from all eligible studies were collected by one author (AA). The following information was extracted: title, author, country of origin, year of publication, study design, participants, interventions, methods, outcome measures and summary of results. The data extraction was carried out using a pre-defined form in Microsoft Excel. A complete description of the extracted data is reported in Supplementary Tables S2, S3 and S4. For the syntheses, reports were categorized by sport (running, cycling, triathlon) and study type (observational versus longitudinal). One reviewer (AA) assessed methodological quality and the potential risk of bias using the JBI Critical Appraisal Tool (Supplementary Table S5) [29].


Study Selection

Our search yielded a total of 13,570 records, published between 1915 and 2022. After deduplication, 9302 unique records were left. 9260 articles were excluded by title and abstract screening. For 12 out of the 42 remaining records, we could not retrieve the full text. The full texts of 30 reports were assessed for eligibility of which 17 studies were excluded based on population or study type. Eventually, 13 studies were included.

Study Characteristics

Eight articles reported on endurance running [19, 30,31,32,33,34,35,36], three on cycling [10, 19, 37], and four on triathlon [19, 38,39,40]. From the 13 eligible articles, seven (54%) had a cross-sectional design [10, 30, 32, 34, 38,39,40] and six (46%) were longitudinal [19, 31, 33, 35,36,37]. In the included articles, different guidelines and criteria for semen analysis were used (Supplementary Table S6). Two studies followed the criteria described by Bremner et al. in 1981 [31, 36], one the Kruger’s strict criteria of 1986 [35], two the Kruger’s strict criteria of 1995 [38, 40], two the WHO 2nd edition of 1987 [32, 34], one the WHO 3th edition of 1992 [19], two the WHO 4th edition of 1999 [10, 38], one the WHO 5th edition of 2010 [39] and three did not specify criteria used for semen analysis [30, 33, 37]. Years of publication ranged from 1985 to 2018. The majority of the articles were published in the United States (n = 7). The country of origin of the remaining articles was Spain (n = 4) and South Africa (n = 2). The included reports identified a total of 280 subjects who underwent semen analysis. However, it is unclear whether two studies used identical subjects [38, 40]. Characteristics of the included articles are presented in Tables 1, 2 and 3.

Table 1 Characteristics of included studies investigating endurance running
Table 2 Characteristics of included studies investigating cycling
Table 3 Characteristics of included studies investigating triathletes

Results of Individual Studies

Cross-Sectional Studies on Running

Three cross-sectional studies, including a total of 88 subjects, investigated the effect of endurance running on semen quality [30, 32, 34]. First, one study reported oligospermia in two out of 20 marathon runners. The mean sperm concentration in the other 18 men was 128 × 106/ml (WHO 6th edition reference threshold for fertile men > 16 × 106/ml) [30]. A second study compared 10 endurance runners with 8 weight lifters and 10 sedentary controls. Sperm concentration was lower in the runners group compared to sedentary controls (78 ± 12 × 106/mL versus 176 ± 25 × 106/ml, p = 0.003), but there were no differences in total sperm count. The runners presented with lower sperm progressive motility (40.8 ± 4.7% versus 58.7 ± 2.4% for controls, p < 0.05) and a lower number of morphologically normal sperm cells (40.2 ± 2.1% versus 47.0 ± 3.3% for controls, p < 0.05) [32]. A third study reported a reduction in sperm concentration (88.5 ± 14.8 × 106/mL versus 175.5 ± 24.9 × 106/ml, p = 0.045), total motile sperm count (134.5 ± 23.9 × 106 versus 224.7 ± 39.1 × 106, p = 0.037) and sperm motility (40.3 ± 4.3% progressive motility versus 58.7 ± 2.4%, p < 0.05) in high mileage runners compared to sedentary controls [34].

Longitudinal Studies on Running

Five longitudinal studies reporting on running were included, comprising a total of 109 subjects [19, 31, 33, 35, 36]. There were no significant alterations in semen parameters when investigating 12 endurance runners during 12 weeks [31]. A second study studied the effect of a two-week overtraining period in 5 endurance sportsmen (including running, swimming or cycling). Sperm concentration dropped immediately after overtraining and remained lower than baseline until three months afterwards (concentration before overtraining: 91 ± 23.3 × 106/ml, immediately after: 52 ± 6.8 × 106/ml, 3 months after overtraining 44.5 ± 20 × 106/ml, p < 0.01). Sperm motility and morphology were not altered, though they included merely five athletes and the precise endurance sport they practiced was not enclosed [33]. A third study investigated the semen profile of 24 men, during a year in which they aimed to participate in a 56 km running competition. The marathon took place five months after the study started and further follow-up was performed until six months after the race. Training programs were progressively more intense in the pre-marathon period and gradually tapered off afterwards. Semen volume (p = 0.044) and sperm motility (p = 0.012) were lower four months after training started compared to baseline measurements. Sperm morphology was altered from one month after start of training until six months after the marathon (p < 0.05). There were no differences in sperm count (p > 0.05). When comparing high to low load training months, in high training months, a higher sperm count (133 × 106/mL for high training and 71 × 106/mL for low training, p = 0.001) and higher percentage of morphologically normal spermatozoa (15% for high training and 11% for low training, p = 0.001) was observed [35]. A fourth study followed 12 professional cyclists, nine elite triathletes and 10 marathon runners during a whole sports season. Semen analysis was performed three times: in the training, competition, and resting period. The investigators performed a mixed design study as they compared semen parameters between the groups, but also within groups during other periods. The results showed lower sperm motility in the runners compared to the cyclists in the resting period (p < 0.05) [19]. A fifth study group investigated the effect of increased training volume followed by a resting period on semen characteristics in eight runners. They did not observe significant group effects. However, two out of eight runners reached oligospermic values during periods of increased training, which spontaneously recovered to normal values after two weeks of rest [36].

To conclude, outcomes on sperm quality in endurance runners are mixed. Four studies did not report significant group effects [19, 30, 31, 36], while four other studies did find sperm alterations [32,33,34,35]. However, only one study described a decrease below the WHO thresholds, which may negatively affect fertility potential[35]. The decreases in semen quality reported by other authors were of statistical significance only as all semen parameters remained above WHO thresholds [32,33,34].

Cross-Sectional Studies on Cycling

Only one cross-sectional study reported on semen quality in endurance cyclists. Semen profiles of 10 non-professional cyclists showed no differences in sperm volume, motility, viability or count compared with 10 sedentary controls. Only morphological abnormalities were more frequent (normal morphology in cyclists 19.5 (18.3–30.8) % versus 41.5 (34.8–55.3) % in sedentary controls, p < 0.01) [10].

Longitudinal Studies on Cycling

Two longitudinal studies, including 46 subjects, assessed the effect of endurance cycling on semen parameters [19, 37]. First, during competition, Lucìa et al. reported reduced sperm motility in 12 cyclists compared to the other groups consisting of triathletes, marathon runners and sedentary controls (p < 0.05), but also when comparing with baseline values and during training periods (p < 0.01). After a resting period, the sperm motility of cyclists normalised and reached even higher values than the runners (p < 0.05). There were no anomalies in sperm morphology [19]. A second study group instructed biathletes to double cycling hours for two weeks without changing cycling intensity or running volume. Oligospermia was noticed in one subject. However, this study was limited by the small sample size, as only six athletes were included and single semen analysis was performed [37].

Cross-Sectional Studies on Triathlon

One study group conducted three cross-sectional studies on semen quality in triathletes[38,39,40]. In the first article, they compared the semen profile of 15 professional triathletes with 14 waterpolo players and 16 physically active men who practiced different ball sports[38]. Total sperm count (141.3 ± 58.0 × 106 in triathletes, versus 191.8 ± 73.4 × 106 ball sports and 196.6 ± 85.4 × 106 for water polo players, p = 0.03) and concentration (48.2 ± 14.7 × 106/mL in triathletes versus 61.0 ± 23.0 × 106/mL in ball sports and 58.0 ± 24.4 × 106/mL in water polo players, p = 0.04) of the triathletes were lower compared to both other groups. Three triathletes even reached oligospermic levels. Sperm morphology was significantly altered compared to both other groups (4.7 ± 2.2% normal forms in triathletes versus 15.2 ± 1.2% in ball sports and 9.7 ± 3.0% in water polo players, p = 0.01). Moreover, in some subjects the number of morphologically normal forms decreased to < 4%, a critical level for Kruger’s strict criteria[41]. For further investigation of this outcome, the relationship between training volume and sperm morphology was investigated in a second study [40]. Although not specified by the authors, we assume data from the same triathletes as in the first study were examined. The results showed no correlation between normal forms and total weekly volume, or between running or swimming mileage (p > 0.05). In contrast, cycling kilometres negatively correlated with normal sperm morphology (p < 0.05). More recently, the same authors carried out a third study in 12 high-level triathletes [39]. Semen analysis showed no abnormal values. However, mean morphology was in the lower margins of normality, with some subjects reaching the < 4% threshold of Kruger’s strict criteria. Besides conventional semen parameters, DNA fragmentation was examined as well and showed higher values, even above the WHO threshold (p < 0.05).

Longitudinal Studies on Triathlon

Only one study reported longitudinal data on seminal characteristics of triathletes and used a mixed design. In contrast with the cross-sectional studies mentioned above, semen parameters did not change over time and remained normal during the whole sports season [19].


Summary of Evidence

In this systematic review, we found that data on the effect of endurance exercise on semen quality is inconsistent. Most studies found no [19, 30, 31, 36, 37] or only subclinical group effects [10, 19, 32,33,34]. When statistically significant differences in semen parameters were observed, absolute values remained above WHO-defined thresholds. However, the limited number of participants and sedentary controls hamper interpretation of the results. Endurance sports alone do not seem to critically disrupt spermatogenesis. However, they could be a decisive factor in men who already have low or low-normal sperm quality. Four trials reported a decrease in certain parameters of semen quality with potential clinical consequences [35, 38,39,40]. The amount of morphologically normal sperm cells was reduced below the threshold of Kruger’s strict criteria in some cyclists and triathletes[35, 38, 40]. Also, sperm DNA fragmentation was higher in triathletes [39].

Endurance exercise may also have long-term effects on semen quality. Comparing with baseline semen analysis, two longitudinal studies reported a statistically significant reduction in sperm concentration and morphology three months after overtraining and eight months after running a marathon, respectively [33, 35]. These long-term alterations may be a reflection of the 70 days to complete spermatogenesis, as germ cells could be damaged at the start of this process. It is unclear to what extent these findings affect clinical fertility potential, since recent literature did not find any association between isolated low percentage of sperm morphology and pregnancy rate [42]. High sperm DNA fragmentation can have a potential negative influence on fertility. However, since there are no recommendations on cut-off values or standard measuring techniques, the clinical relevance remains unclear [16, 43]. In general, sperm concentration and motility are the most important parameters with respect to pregnancy rate [42]. Since none of the included studies observed changes in these parameters, our study suggests that endurance exercise has no major impact on fertility potential. Interestingly, a recent retrospective study observed that male professional soccer players fathered more girls than boys. Of the 122 children born, there were 52 boys (42.6%) versus 70 girls (57.4%) and differences in training volume and intensity significantly impacted the birth offspring ratio more towards females [44]. Endurance exercise could thus potentially impact reproductive parameters in a more complex way, warranting more research on underlying mechanisms and effects.

Several mechanisms have been suggested to explain how endurance exercise could affect semen quality. A recurring hypothesis is the “volume threshold”, which suggested that a certain training load for running (> 104 km/w) or cycling (> 300 km/w) negatively affects sperm quality [34, 40]. This hypothesis can be questioned, because the cycling threshold was based on morphological alterations and other studies could not find significant sperm alterations despite attaining these thresholds [19, 36]. In contrast to training load, exercise intensity can be more important [35]. However, neither training load nor exercise intensity can fully explain the underlying mechanism, as multiple factors may influence spermatogenesis. Both reproductive hormone levels and BMI remained in the normal range in all of the included studies that reported these parameters [45]. In addition to BMI, energy balance should be examined more thoroughly to obtain more insight on LEA. In one study professional cyclists exhibited altered sperm motility [19]. However, since mean testosterone levels and body fat percentage remained normal, it is unlikely that hormonal suppression or undernutrition are responsible for these sperm alterations.

To date, this field of research faces many methodological challenges. First of all, the term “endurance exercise” is open to interpretation because there is no consensus on minimal training hours or volume to be attained. Second, setting up a standardised study design is complicated because various factors such as scrotal temperature, saddle position, training load, intensity and energy balance should be controlled. Third, there is a lack of standardisation in semen analysis. For example, one study in endurance runners had a time delay of more than 24 h between sample production and analysis, whereas sample production and analysis should be performed within one hour [31]. Among the included studies, there are also important differences between the number of semen samples analysed and abstinence time is not always disclosed. This is of significance because higher abstinence time is associated with lower motility and higher DNA damage. To account for individual variability in semen parameters, two consecutive semen samples should be examined [24, 26]. Furthermore, because of the small number of participants and the absence of a control group in several studies, it is unclear if observed differences in semen characteristics are merely due to normal variation or indeed induced by exercise.

In recent decades, there have been multiple guidelines made available regarding examination of human spermatozoa (Supplementary Table S6) [46]. This resulted in heterogeneous results and interpretations, but also in difficulties in comparing studies. Moreover, recent literature showed a lack of adherence to the standardised WHO guidelines for semen analysis [47]. Inadequate methodology causes measurement uncertainty with inaccurate results. Therefore, the reproducibility and reliability of previously published data can be questioned [25]. Finally, some of the included studies were rather old and a notable proportion were carried out by the same authors, especially regarding triathlon. To address these methodological concerns, future researchers are recommended to follow the laboratory methods and corresponding checklist proposed by Björndahl et al. in 2022 [25].

Strengths and Limitations

This systematic review has certain strengths. Because of our detailed search strategy, we conducted a comprehensive search for evidence, which enabled us to systematically evaluate the impact of endurance exercise on semen quality of male athletes. To avoid reporting bias, two investigators independently screened the obtained articles for eligibility. A formal assessment of bias in the included evidence was conducted using an approved tool. To report transparently, this systematic review was written following the PRISMA 2020 statement (Supplementary Appendix S1) [27].

Our study has also some limitations. Data extraction was done by one reviewer. Even though this research domain covers a long time period, the number of eligible studies was small. Some of the studies were rather old. The majority lacked methodological quality and had a small sample size. To assess semen quality, each parameter was evaluated separately. However, it is possible that a combination of multiple disrupted parameters (e.g., low concentration together with low progressive motility) may have an effect on reproductive function. Moreover, when assessing sperm parameters, interobserver variation for morphology, for example, is larger than for concentration. This adds to the difficulty comparing between studies.


This systematic review shows that endurance exercise can have a negative effect on semen quality, although rarely with clinical relevance on fertility potential. In general, semen parameters, especially concentration and motility, remained above WHO defined thresholds. The obtained data were highly affected by small sample sizes and methodological pitfalls, which may have led to measurement uncertainty. Therefore, there is a need for future research of high methodological quality to further assess the relationship between endurance exercise and semen quality.

Availability of Data and Material

Data sharing is not applicable to this article as no datasets were generated or analyzed during the current study.



World Health Organisation


Low energy availability


Hypogonadal-pituitary–gonadal axis


Gonadotropin-releasing hormone


Thyroid-stimulating hormone


Luteinizing hormone


Relative energy deficiency in sport


Reactive oxygen species


Anabolic androgenic steroids


Preferred Reporting Items for Systematic reviews and Meta-Analyses


Metabolic equivalent of task


  1. Pedersen BK, Saltin B. Evidence for prescribing exercise as therapy in chronic disease. Scand J Med Sci Sports. 2006;16(Suppl 1):3–63.

    Article  PubMed  Google Scholar 

  2. Jürimäe J, Mäestu J, Jürimäe T, Mangus B, von Duvillard SP. Peripheral signals of energy homeostasis as possible markers of training stress in athletes: a review. Metabolism. 2011;60(3):335–50.

    Article  PubMed  Google Scholar 

  3. Hakimi O, Cameron LC. Effect of exercise on ovulation: a systematic review. Sports Med. 2017;47(8):1555–67.

    Article  PubMed  Google Scholar 

  4. Hackney AC. Hypogonadism in exercising males: dysfunction or adaptive-regulatory adjustment? Front Endocrinol (Lausanne). 2020;11:11.

    Article  PubMed  Google Scholar 

  5. Vaamonde D, Da Silva ME, Poblador MS, Lancho JL. Reproductive profile of physically active men after exhaustive endurance exercise. Int J Sports Med. 2006;27(9):680–9.

    Article  CAS  PubMed  Google Scholar 

  6. Matos B, Howl J, Ferreira R, Fardilha M. Exploring the effect of exercise training on testicular function. Eur J Appl Physiol. 2019;119(1):1–8.

    Article  CAS  PubMed  Google Scholar 

  7. Mountjoy M, Sundgot-Borgen J, Burke L, Carter S, Constantini N, Lebrun C, Meyer N, Sherman R, Steffen K, Budgett R, Ljungqvist A. The IOC consensus statement: beyond the female athlete triad-relative energy deficiency in sport (RED-S). Br J Sports Med. 2014;48(7):491–7.

    Article  PubMed  Google Scholar 

  8. Dipla K, Kraemer RR, Constantini NW, Hackney AC. Relative energy deficiency in sports (RED-S): elucidation of endocrine changes affecting the health of males and females. Hormones (Athens). 2021;20(1):35–47.

    Article  PubMed  Google Scholar 

  9. Jung A, Leonhardt F, Schill WB, Schuppe HC. Influence of the type of undertrousers and physical activity on scrotal temperature. Hum Reprod. 2005;20(4):1022–7.

    Article  CAS  PubMed  Google Scholar 

  10. Gebreegziabher Y, Marcos E, McKinon W, Rogers G. Sperm characteristics of endurance trained cyclists. Int J Sports Med. 2004;25(4):247–51.

    Article  CAS  PubMed  Google Scholar 

  11. Bedford JM. Human spermatozoa and temperature: the elephant in the room. Biol Reprod. 2015;93(4):97.

    Article  PubMed  Google Scholar 

  12. Durairajanayagam D, Agarwal A, Ong C. Causes, effects and molecular mechanisms of testicular heat stress. Reprod Biomed Online. 2015;30(1):14–27.

    Article  CAS  PubMed  Google Scholar 

  13. Sachdev S, Davies KJ. Production, detection, and adaptive responses to free radicals in exercise. Free Radic Biol Med. 2008;44(2):215–23.

    Article  CAS  PubMed  Google Scholar 

  14. Turner JE, Hodges NJ, Bosch JA, Aldred S. Prolonged depletion of antioxidant capacity after ultraendurance exercise. Med Sci Sports Exerc. 2011;43(9):1770–6.

    Article  PubMed  Google Scholar 

  15. Gibb Z, Griffin RA, Aitken RJ, De Iuliis GN. Functions and effects of reactive oxygen species in male fertility. Anim Reprod Sci. 2020;220:106456.

    Article  CAS  PubMed  Google Scholar 

  16. Farkouh A, Salvio G, Kuroda S, Saleh R, Vogiatzi P, Agarwal A. Sperm DNA integrity and male infertility: a narrative review and guide for the reproductive physicians. Transl Androl Urol. 2022;11(7):1023–44.

    Article  PubMed  PubMed Central  Google Scholar 

  17. Knez WL, Coombes JS, Jenkins DG. Ultra-endurance exercise and oxidative damage: implications for cardiovascular health. Sports Med. 2006;36(5):429–41.

    Article  PubMed  Google Scholar 

  18. Gemery JM, Nangia AK, Mamourian AC, Reid SK. Digital three-dimensional modelling of the male pelvis and bicycle seats: impact of rider position and seat design on potential penile hypoxia and erectile dysfunction. BJU Int. 2007;99(1):135–40.

    Article  PubMed  Google Scholar 

  19. Lucia A, Chicharro JL, Perez M, Serratosa L, Bandres F, Legido JC. Reproductive function in male endurance athletes: sperm analysis and hormonal profile. J Appl Physiol. 1996;81(6):2627–36.

    Article  CAS  PubMed  Google Scholar 

  20. de Kretser DM, Loveland KL, Meinhardt A, Simorangkir D, Wreford N. Spermatogenesis. Hum Reprod. 1998;13(Suppl 1):1–8.

    Article  PubMed  Google Scholar 

  21. Amann RP. The cycle of the seminiferous epithelium in humans: a need to revisit? J Androl. 2008;29(5):469–87.

    Article  PubMed  Google Scholar 

  22. Sharma A, Jayasena CN, Dhillo WS. Regulation of the hypothalamic-pituitary-testicular axis: pathophysiology of hypogonadism. Endocrinol Metab Clin North Am. 2022;51(1):29–45.

    Article  PubMed  Google Scholar 

  23. Bjorndahl L, Kirkman J. Laboratory manual for the examination and processing of human semen: ensuring quality and standardization in basic examination of human ejaculates. Fertil Steril. 2022;117(2):246–51.

    Article  PubMed  Google Scholar 

  24. Keihani S, Craig JR, Zhang C, Presson AP, Myers JB, Brant WO, Aston KI, Emery BR, Jenkins TG, Carrell DT, Hotaling JM. Impacts of abstinence time on semen parameters in a large population-based cohort of subfertile men. Urology. 2017;108:90–5.

    Article  PubMed  Google Scholar 

  25. Björndahl L, Barratt CLR, Mortimer D, Agarwal A, Aitken RJ, Alvarez JG, Aneck-Hahn N, Arver S, Baldi E, Bassas L, Boitrelle F, Bornman R, Carrell DT, Castilla JA, Cerezo Parra G, Check JH, Cuasnicu PS, Darney SP, de Jager C, De Jonge CJ, Drevet JR, Drobnis EZ, Du Plessis SS, Eisenberg ML, Esteves SC, Evgeni EA, Ferlin A, Garrido N, Giwercman A, Goovaerts IGF, Haugen TB, Henkel R, Henningsohn L, Hofmann MC, Hotaling JM, Jedrzejczak P, Jouannet P, Jørgensen N, Kirkman Brown JC, Krausz C, Kurpisz M, Kvist U, Lamb DJ, Levine H, Loveland KL, McLachlan RI, Mahran A, Maree L, Martins da Silva S, Mbizvo MT, Meinhardt A, Menkveld R, Mortimer ST, Moskovtsev S, Muller CH, Munuce MJ, Muratori M, Niederberger C, O’Flaherty C, Oliva R, Ombelet W, Pacey AA, Palladino MA, Ramasamy R, Ramos L, Rives N, Roldan ER, Rothmann S, Sakkas D, Salonia A, Sánchez-Pozo MC, Sapiro R, Schlatt S, Schlegel PN, Schuppe HC, Shah R, Skakkebæk NE, Teerds K, Toskin I, Tournaye H, Turek PJ, van der Horst G, Vazquez-Levin M, Wang C, Wetzels A, Zeginiadou T, Zini A. Standards in semen examination: publishing reproducible and reliable data based on high-quality methodology. Hum Reprod. 2022;37(11):2497–502.

    Article  PubMed  PubMed Central  Google Scholar 

  26. Blickenstorfer K, Voelkle M, Xie M, Fröhlich A, Imthurn B, Leeners B. Are WHO recommendations to perform 2 consecutive semen analyses for reliable diagnosis of male infertility still valid? J Urol. 2019;201(4):783–91.

    Article  PubMed  Google Scholar 

  27. Page MJ, McKenzie JE, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD, Shamseer L, Tetzlaff JM, Akl EA, Brennan SE, Chou R, Glanville J, Grimshaw JM, Hróbjartsson A, Lalu MM, Li T, Loder EW, Mayo-Wilson E, McDonald S, McGuinness LA, Stewart LA, Thomas J, Tricco AC, Welch VA, Whiting P, Moher D. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ. 2021;372:n71.

    Article  PubMed  PubMed Central  Google Scholar 

  28. Rethlefsen ML, Kirtley S, Waffenschmidt S, Ayala AP, Moher D, Page MJ, Koffel JB. PRISMA-S: an extension to the PRISMA Statement for Reporting Literature Searches in Systematic Reviews. Syst Rev. 2021;10(1):39.

    Article  PubMed  PubMed Central  Google Scholar 

  29. Aromataris E, Fernandez R, Godfrey CM, Holly C, Khalil H, Tungpunkom P. Summarizing systematic reviews: methodological development, conduct and reporting of an umbrella review approach. Int J Evid Based Healthc. 2015;13(3):132–40.

    Article  PubMed  Google Scholar 

  30. Ayers JW, Komesu Y, Romani T, Ansbacher R. Anthropomorphic, hormonal, and psychologic correlates of semen quality in endurance-trained male athletes. Fertil Steril. 1985;43(6):917–21.

    Article  CAS  PubMed  Google Scholar 

  31. Bagatell CJ, Bremner WJ. Sperm counts and reproductive hormones in male marathoners and lean controls. Fertil Steril. 1990;53(4):688–92.

    Article  CAS  PubMed  Google Scholar 

  32. Arce JC, De Souza MJ, Pescatello LS, Luciano AA. Subclinical alterations in hormone and semen profile in athletes. Fertil Steril. 1993;59(2):398–404.

    Article  CAS  PubMed  Google Scholar 

  33. Roberts AC, McClure RD, Weiner RI, Brooks GA. Overtraining affects male reproductive status. Fertil Steril. 1993;60(4):686–92.

    Article  CAS  PubMed  Google Scholar 

  34. De Souza MJ, Arce JC, Pescatello LS, Scherzer HS, Luciano AA. Gonadal hormones and semen quality in male runners. A volume threshold effect of endurance training. Int J Sports Med. 1994;5(7):383–91.

    Article  Google Scholar 

  35. Jensen CE, Wiswedel K, McLoughlin J, van der Spuy Z. Prospective study of hormonal and semen profiles in marathon runners. Fertil Steril. 1995;64(6):1189–96.

    Article  CAS  PubMed  Google Scholar 

  36. Hall HL, Flynn MG, Carroll KK, Brolinson PG, Shapiro S, Bushman BA. Effects of intensified training and detraining on testicular function. Clin J Sport Med. 1999;9(4):203–8.

    Article  CAS  PubMed  Google Scholar 

  37. Griffith RO, Dressendorfer RH, Fullbright CD, Wade CE. Testicular function during exhaustive endurance training. Phys Sportsmed. 1990;18(5):54–64.

    Article  CAS  PubMed  Google Scholar 

  38. Vaamonde D, Da Silva-Grigoletto ME, García-Manso JM, Vaamonde-Lemos R, Swanson RJ, Oehninger SC. Response of semen parameters to three training modalities. Fertil Steril. 2009;92(6):1941–6.

    Article  PubMed  Google Scholar 

  39. Vaamonde D, Algar-Santacruz C, Abbasi A, García-Manso JM. Sperm DNA fragmentation as a result of ultra-endurance exercise training in male athletes. Andrologia. 2018;50(1):e12793.

    Article  Google Scholar 

  40. Vaamonde D, Da Silva-Grigoletto ME, García-Manso JM, Cunha-Filho JS, Vaamonde-Lemos R. Sperm morphology normalcy is inversely correlated to cycling kilometers in elite triathletes. Revista Andaluza de Med Deporte. 2009;2(2):43–6.

    Google Scholar 

  41. van der Merwe FH, Kruger TF, Oehninger SC, Lombard CJ. The use of semen parameters to identify the subfertile male in the general population. Gynecol Obstet Invest. 2005;59(2):86–91.

    Article  PubMed  Google Scholar 

  42. Del Giudice F, Belladelli F, Chen T, Glover F, Mulloy EA, Kasman AM, Sciarra A, Salciccia S, Canale V, Maggi M, Ferro M, Busetto GM, De Berardinis E, Salonia A, Eisenberg ML. The association of impaired semen quality and pregnancy rates in assisted reproduction technology cycles: Systematic review and meta-analysis. Andrologia. 2022;54(6):e14409.

    PubMed  PubMed Central  Google Scholar 

  43. Alahmar AT, Singh R, Palani A. Sperm DNA fragmentation in reproductive medicine: a review. J Hum Reprod Sci. 2022;15(3):206–18.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  44. Vaamonde D, Hackney AC, Garcia Manso JM, Arriaza Ardiles E, Vaquero M. Birth sex ratio in the offspring of professional male soccer players: influence of exercise training load. Hum Reprod. 2020;35(11):2613–8.

    Article  CAS  PubMed  Google Scholar 

  45. Meeker JD, Godfrey-Bailey L, Hauser R. Relationships between serum hormone levels and semen quality among men from an infertility clinic. J Androl. 2007;28(3):397–406.

    Article  CAS  PubMed  Google Scholar 

  46. Wang C, Mbizvo M, Festin MP, Bjorndahl L, Toskin I. Editorial Board Members of the, and S. Processing of Human, Evolution of the WHO "Semen" processing manual from the first (1980) to the sixth edition. Fertil Steril, 2022 117(2): 237–245

  47. Vasconcelos AL, Campbell MJ, Barratt CLR, Gellatly SA. Do studies published in two leading reproduction journals between 2011 and 2020 demonstrate that they followed WHO5 recommendations for basic semen analysis? Hum Reprod. 2022;37(10):2255–63.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

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LA receives a senior clinical research fellowship from Research Foundation Flanders (1800923N).

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All authors contributed to the study’s conception and design. AA conducted database searches and article identification. AA and AT conducted the independent screening process. AA wrote the first draft of the manuscript. All authors provided input on interpretation of the results and commented on the manuscript. All authors read and approved the final manuscript.

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Correspondence to Leen Antonio.

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Aerts, A., Temmerman, A., Vanhie, A. et al. The Effect of Endurance Exercise on Semen Quality in Male Athletes: A Systematic Review. Sports Med - Open 10, 72 (2024).

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