“Saving Swimmers” - the effects of training, mechanical stress and performance-enhancing drugs on male fertility Dr Jon Patricios, Sports Physician The last 2 decades have seen significant changes in exercising patterns amongst both professional and recreational athletes. Endurance running and mass cycling events, many of them multi-stage, have increased in popularity whilst triathlon has become one of the fastest-growing sports. As much as these levels of exercise participation may be viewed as positive, negative trends have also emerged including an increasing use of anabolic steroids especially in recreational athletes, many of them young. Over the same period there has been an increasing incidence of infertility (described as the inability to achieve a successful pregnancy after 12 months of regular unprotected intercourse). Is there a link between exercise trends and male infertility and should men be more proactive to improve their chances of producing offspring? Intense exercise – stifling sperm Exercise is accepted as being healthy for all aspects of our physical and mental wellbeing. Testicular function is no exception. Animal and human models have demonstrated slower rates of age-related decline in testicular function reflected by higher levels of circulating testosterone, higher concentration of sperm in semen and better sperm motility than in non-exercised animals. However, intense exercise may have more deleterious effects on semen and fertility. There is growing evidence and concern that exercise, when excessively practiced, may lead to adverse effects on the reproductive system and fertility. This occurs when exercise, itself a stress on the body, is increased in duration and or intensity and challenges the body’s ability to maintain homeostasis (its sense of physiological balance). There appears to be a volume threshold for the effect of training on sperm parameters and hormones. In other words, the beneficial effects of exercise on the male reproductive system are only produced to a certain intensity of exercise. Such a threshold has been observed both in running and in cycling. Running dry and pedaling poor High mileage runners (greater than 95km/week) have been found to have far poorer parameters of sperm health including sperm that are lower in number, more abnormal-looking, less motile and less effective at penetrating mucus, and a volume of 300km/week in cycling correlates with potential fertility impairment from a sperm morphology point of view When endurance-trained and resistance-trained athletes were compared with sedentary controls, sperm density, motility, morphology and sperm penetration of standard cervical mucus were significantly altered only in the endurancetrained runners. Training volume (expressed as km/week), was significantly correlated to sperm motility and density. In another study, in which 286 exercising subjects were divided into moderateintensity exercise (60% of VO2max) and high-intensity exercise (80% of VO2max) groups, midway through the running- phase the subjects in the highintensity exercise group showed a significant decline in semen parameters compared to those athletes exercising at moderate intensity. The changes reversed during recovery but the researchers correctly point out that the deleterious effects may not be reversible if athletes have been training for longer periods of time (years) or had started training around puberty. It is important to place these findings in perspective. Almost all studies have found that changes tend to be temporary, correcting within days to weeks. Moreover, even a below-average sperm count doesn’t necessarily make that individual infertile. However, little information is available on athletes who regularly engage in high mileage training week in and week out. This may be a group at higher risk of chronic low sperm count and abnormal morphology. Cycling – sacrificing swimmers Professional cyclists have been shown to consistently have higher testosterone levels than most sportsmen. However, their sperm motility and morphology (shape) appears to be worse than average especially during competition. Postulated reasons include the increased testicular temperatures and the psychological stress associated with competition. One function of the scrotum is to keep the testes outside of the body and at a lower temperature to the core. Testicular temperature must be maintained at approximately 2.5°C below core body temperature for normal spermatogenesis. The regulatory role of the scrotum in sustaining this lowered testicular temperature is achieved through the combined function of the cremasteric and dartos muscles (by moving the testicles closer or further away from the body) as well as the venous plexus of the spermatic cord (acting as a counter-current heat exchanger). Cycling counters this with tight-fitting shorts and a saddle that compress the testes close to the body. In other forms of exercise vascular shunting away from the scrotum combined with increased air circulation around the scrotum actually decreases scrotal temperature during exercise. A study on mountain bikers found 96% to have scrotal abnormalities as compared to 48% of road cyclists and 16% of controls. Testicular calcifications, hydroceles (small, fluid-filled sacks) and varicoceles (enlarged, twisted scrotal veins) were all more common. All these abnormalities could affect reproductive health. Again, this does not necessarily correlate with infertility but is a reflection of the potential effects of repetitive microtrauma. In summary, as with most areas of human physiology, testicular health is enhanced by regular low to moderate intensity exercise but there is evidence from both animal and human studies that suggests that long-duration and intense exercise may compromise hormonal status and adversely affect sperm production and morphology. Cycling in particular, because of raised testicular temperatures and repetitive microtrauma, may predispose to poor sperm health. Erectile dysfunction Recurrent testicular trauma Hormonal imbalances Oxidative exercise stress Male factor Infertility Raised testicular temperature Adapted from Du Plessis S et al. Is There a Link between Exercise and Male Factor Infertility? The Open Reproductive Science Journal, 2011, 3, 105-113 Destructive doping Testosterone was first isolated as a substance in 1935 and, since then, the use of testosterone-derived anabolic androgenic steroids (“steroids”) has been described in body builders and sports cheats for decades, starting with Russian weightlifters in the 1950’s. However, the use of steroids has extended to recreational athletes and even schoolchildren. In the USA steroid use is estimated to be 3 million with two thirds being recreational users principally for aesthetic purposes. Moreover, commercially available supplements have a steroid contamination rate of 15-20%. Exposure to these drugs at a young age may result in them having significant effects on a developing body and longer use may result in an exponential increase in side effects. One of these effects is infertility. Up to 50% of cases of infertility are accounted for by the male. The “underground” culture of steroid use and abuse results in little interaction between users and medical professionals often until infertility is eventually diagnosed. There is a considerable body of scientific evidence that the use of steroids negatively affects male fertility. The effects of the testosterone-derived steroids results in testicular atrophy (shrinking testes), oligospermia (fewer sperm) and azoospermia (deformed sperm). Simply put, using anabolic steroids not only reduces the number of sperm but affects their quality. These effects result from a dampening effect that steroids have on the areas of the brain that regulate hormone production as well as a direct toxic effect on the testes. Therefore, somewhat ironically, although blood levels of testosteronederived steroids are high, the small, inefficient testes produce fewer healthy sperm. In one study, sperm counts fell by 73% and in three individuals azoospermia (complete absence of sperm) was present when high doses of anabolic steroids were taken chronically. Even in those individuals with sperms present, there was a 10% increase in the number of immotile sperm and a 30% decrease in the number of motile sperms. Thus, fertility was severely reduced in males, which provides confirmation of many clinical reports of the same phenomena. In another study conducted on bodybuilders in Parma, Italy, the two most enduring effects of 2 years of steroid use were elevated cholesterol and reduced altered sperm count and morphology resulting in a lower fertility index. In addition, low levels of the body’s own (endogenous) testosterone result in low libido and erectile dysfunction further diminishing the prospects for reproduction. Abnormalities in sperm parameters may correct in 4-12 months but much longer effects have been documented particularly where high doses, multiple steroids (“stacking”) and long-duration use have taken place. There are documented cases of the testosterone-producing Leydig cells, never recovering. Treatment of steroid-induced infertility takes several forms. A passive approach is to wait for correction of the hormonal status and for normal sperm production to resume. This may take months to years. A more proactive intervention involves stimulation with a group of drugs known as gonadotropin analogues including human chorionic gonadotropin (hCG), recombinant menopausal gonadotropin (rMG) and follicular stimulating hormone (FSH). Some steroid users are now proactively using hCG as part of their drug regimen especially after a steroids cycle to try and mitigate the effects of steroids on sperm. Cases of sperm correction have been noted but most often the sperm abnormal in morphology and hypomobile (“slow”). In other words, using hCG concomitantly with steroids may help to maintain sperm count but the quality of sperm remains poor. The steroid abuser is still left with “bad swimmers”. Differing patterns in steroid use, types of drug, doses, regimens as well as individual tolerance of these drugs makes predicting their effects very difficult. There is, however, a substantial enough body of evidence to illustrate the deleterious effects that anabolic steroid use has on male fertility. Sporting and recreational users who wish to have children should consider pro-active steps including regular monitoring by a urologist and fertility clinic and preserving sperm before embarking on the use of such drugs. A Solution – “Saving the swimmers” The sporting public, many of whom are in their reproductive years, should be aware that high intensity exercise may have an effect on sperm count and quality through systemic hormonal changes, local unfavourable temperatures and microtrauma. High load training and steroid use should form part of any modern-day medical history. The fertility consequences of both training and steroid use may be short or longer-term and vary between individuals. Banking sperm whilst still healthy has been used proactively by men for many reasons including before undergoing cancer treatments, prostate surgery or vasectomy and also for those entering high-risk occupations which expose them to extremes of heat, radiation and chemicals. With Netcells Biosciences he cost is under R5 000 which includes a year’s storage but sperm may be stored indefinitely for a small annual storage fee. Once needed, insemination can take place at any fertility clinic of your choice. This knowledge, together with an appreciation of the much greater financial and emotional costs of infertility treatment, make self-donation and preservation of sperm in a sperm bank appear to be a logical and cost-effective means of preserving reproductive potential. “Saving swimmers” may yet salvage a sportsman’s seed.
© Copyright 2018