Varicocele in Athletes: Causes and the Link with Training Load and Pharmacology

Varicocele — a dilation of the veins of the pampiniform plexus of the spermatic cord — is one of the most frequent findings in male urology. Among athletes it raises two natural questions: whether heavy weightlifting can cause it and how it combines with hormonal drugs. The editorial team examines what is known about this from evidence-based medicine and what remains speculation.

What varicocele is

Blood drains from the testicle through a dense network of veins — the pampiniform plexus, which then passes into the testicular vein. When the valves of these veins work inefficiently, blood stagnates and flows in the reverse direction, and the veins dilate and become tortuous. It is this condition that is called varicocele.

Varicocele occurs in about 15% of adult men in the general population, and in the vast majority of cases — on the left. Among men who seek help for infertility, it is detected much more often: according to reviews, in about a third of patients with primary infertility and even more often with secondary infertility (Jensen et al., 2017).

Dilated veins disrupt the temperature regulation of the testicle. Spermatogenesis requires a temperature a few degrees lower than body temperature, and the stagnation of warm venous blood disrupts this balance. Among other mechanisms discussed are oxidative stress, tissue hypoxia, and the backflow of metabolites from the renal vein.

It is important to understand that in many men varicocele causes no problems at all: they have normal fertility and feel no symptoms. So the finding itself is not a reason for panic, but it is a reason for observation.

Anatomical causes

The predominance of left-sided varicocele is explained by anatomy. The left testicular vein is longer than the right and drains into the left renal vein at almost a right angle, whereas the right drains at an acute angle directly into the inferior vena cava. A longer vertical column of blood and less favorable hemodynamics raise the pressure in the left system.

The second factor is insufficiency or absence of the venous valves, which is most likely congenital in nature. The third is the so-called nutcracker phenomenon, when the left renal vein is compressed between the aorta and the superior mesenteric artery, and the pressure in it is transmitted to the testicular vein.

Varicocele usually forms during puberty, when the blood supply to the testicles increases. That is why it is more often detected in adolescents and young men, and only rarely appears for the first time in adulthood. A sudden varicocele in an adult, especially a right-sided one or one that does not collapse when lying down, requires a search for a secondary cause — for example, a mass in the retroperitoneal space or vein thrombosis.

So the main causes of varicocele are anatomical and congenital. Training and drugs can affect its course and consequences, but they rarely act as the primary factor.

The role of physical loads

The popular belief that heavy squats and deadlifts “cause” varicocele has a logical basis: during straining with breath-holding (the Valsalva maneuver), intra-abdominal pressure rises sharply, and with it the pressure in the veins that drain the testicle. It is the Valsalva maneuver that doctors use to detect varicocele during examination.

However, there is no convincing evidence that strength training causes varicocele in a person with normal valves. Studies in athletes are few, with small samples and heterogeneous methods, so their results are contradictory. The cautious conclusion is this: loads associated with high intra-abdominal pressure can theoretically worsen an already existing varicocele and its symptoms, but they are not a proven root cause.

Another factor is temperature. Prolonged sitting on a bicycle saddle, tight compression clothing, and a sauna after training can additionally raise scrotal temperature. For a person with varicocele this is one more factor affecting spermatogenesis, although its contribution is hard to quantify.

Finally, a groin or scrotal injury in contact sports can cause swelling and pain, which an athlete perceives as an “exacerbation” of varicocele. Such conditions require separate diagnosis, since a hematoma, testicular torsion, or an inguinal hernia may be hidden under the guise of pain.

• Proven: an anatomical predisposition and valve insufficiency are the basis of varicocele.
• Likely: high intra-abdominal pressure worsens stasis in already dilated veins.
• Not proven: that strength training by itself causes varicocele.

The link with pharmacology

Anabolic-androgenic steroids do not cause varicocele directly, but they affect the same target — spermatogenesis. Exogenous androgens suppress the production of luteinizing and follicle-stimulating hormones, because of which the testicles shrink and sperm production decreases, up to complete azoospermia (Rahnema et al., 2014). Recovery after stopping can take months, and in some men it remains incomplete.

In a person with varicocele these two factors can overlap: varicocele already lowers sperm quality, and hormonal suppression “switches off” spermatogenesis completely. After stopping the drugs, such a man has worse baseline conditions for recovery. In clinical practice this means that a fertility assessment must take both factors into account at once.

Varicocele is also associated with reduced Leydig cell function and a lower testosterone level in some patients. This sometimes becomes an argument for taking testosterone on one's own, which is the wrong path: exogenous testosterone suppresses spermatogenesis even more strongly. Endocrine Society guidelines explicitly do not recommend testosterone therapy for men who are planning to have children.

Worth mentioning separately are the risks associated with erythrocytosis and clotting changes against the background of androgens, as well as the use of agents that raise intra-abdominal pressure when performing exercises “to the max.” To summarize: pharmacology does not create varicocele, but it can substantially worsen its consequences for reproductive health.

Manifestations and grades

Most often varicocele is detected by chance — during a preventive examination, a medical board, or an examination for infertility. Some men feel a pulling pain or a sensation of heaviness in the scrotum, which worsens with prolonged standing, after training, or in the heat, and decreases when lying down.

With pronounced varicocele the dilated veins are visible or palpable as a “bag of worms” above the testicle. Long-standing varicocele may be accompanied by a decrease in the volume of the testicle on the affected side, which is especially important to assess in adolescents.

For clinical classification the Dubin and Amelar scale (1970) is widely used, which takes into account how easily the veins can be detected on examination. Subclinical varicocele, visible only on ultrasound examination, is singled out separately; according to guidelines, its treatment to improve fertility is not recommended.

The grade of varicocele correlates with the risk of disorders, but does not by itself determine the treatment decision — the semen analysis results, testicular volume, symptoms, and plans regarding children also matter.

Editorial conclusions

Varicocele is a common, predominantly left-sided condition, whose basis is the anatomy of venous drainage and valve insufficiency. Strength loads with high intra-abdominal pressure can worsen the symptoms of an already existing varicocele, but there is no evidence that they are its cause.

The most important link with sport concerns pharmacology: androgens suppress spermatogenesis, and in combination with varicocele the risk to fertility rises substantially. Taking testosterone “to compensate” in the presence of varicocele is a mistaken strategy.

Men who have found dilated scrotal veins, pain, or a decrease in the testicle should see a urologist and undergo an examination, especially if they are planning to have children.

We also recommend reading our articles on the prevention and diagnosis of varicocele, on semen analysis in athletes, and on recovery of the hormonal system after androgens.

References

1. Jensen CFS, Østergren P, Dupree JM, et al. Varicocele and male infertility. Nat Rev Urol. 2017;14(9):523–533.
2. Minhas S, Bettocchi C, Boeri L, et al. European Association of Urology Guidelines on Male Sexual and Reproductive Health: 2021 Update on Male Infertility. Eur Urol. 2021;80(5):603–620.
3. Practice Committee of the American Society for Reproductive Medicine. Report on varicocele and infertility: a committee opinion. Fertil Steril. 2014;102(6):1556–1560.
4. Dubin L, Amelar RD. Varicocele size and results of varicocelectomy in selected subfertile men with varicocele. Fertil Steril. 1970;21(8):606–609.
5. Rahnema CD, Lipshultz LI, Crosnoe LE, et al. Anabolic steroid-induced hypogonadism: diagnosis and treatment. Fertil Steril. 2014;101(5):1271–1279.
6. Bhasin S, Brito JP, Cunningham GR, et al. Testosterone therapy in men with hypogonadism: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2018;103(5):1715–1744.