A recent study, published in the journal Fertility and Sterility, indicates that perceived stress and stressful life events, but not work-related stress, are associated with semen quality such as sperm concentration, motility and morphology, and thus, male infertility.
In recent times, the crucial role that modifiable lifestyle factors play in the development of male infertility have generated a growing interest in this field of study, i.e. aging, psychological stress, nutrition, physical activity, caffeine, high scrotal temperature, hot water, mobile telephone use.
Several studies have investigated associations between semen quality and the presence of lifestyle stressors i.e. occupational, life events (war, earthquake, etc.) or couple infertility; overall, these studies provide evidence that semen quality is impaired by psychological stress.
According to a recent review article in Nature Reviews Urology a close relationship seems to exist between the testes and the stress system. Psychological stress is linked to reduced paternity, abnormal semen parameters and decreased spermatogenesis. As stress is also associated with a decrease in free testosterone levels, this in turn may have a knock-on effect on spermatogenesis and male infertility (Nat Rev Urol. 2015; 12:373).
The pre-clinical data show that acute stress might impair testicular function; testicular tissue from stressed rats shows higher levels of cortisol displayed apoptosis of both germ cells and Leydig cells. By contrast, the net effects of stress might be determined by chronic as demonstrated by the presence of glucocorticoid receptors (GRs) in Leydig, Sertoli and germs cells; permanently high levels of glucocorticoid are believed to induce apoptosis of all cell types. The Leydig cell is the primary target of glucocorticoid regulation in the testes.
Also, actively coping with stress, such as being assertive or confrontational, may negatively impact on male infertility, by increasing adrenergic activation, leading to more vasoconstriction in the testes. This vasoconstriction results in a lower testosterone level and decreased spermatogenesis.
One study detected linear negative associations between perceived stress and sperm motility, sperm concentration, and percentage of morphologically normal spermatozoa. The other study did not find any association between stress and semen parameters, but found that fecundability decreased with increasing stress score in men with low semen quality.
In the Fertility and Sterility study, Teresa Janevic and colleagues from the Rutgers School of Public Health, New Brunswick, New Jersey assessed 193 men as part of the study of the environment and reproduction at the Kaiser Foundation health plan in the Oakland, California, area.
The authors found an inverse association between perceived stress score and sperm concentration. In addition, they report that men who experienced stressful life events in the past year had a lower percentage of motile sperm and a lower percentage of sperm of normal morphology.
This is first study of semen quality and male infertility using three dimensions of stress, and where life stress was measured both subjectively (Perceived Stress Scale) and objectively (Life Events Inventory). It appeared that the Perceived Stress Scale, not previously used in studies of semen quality, best captured the association between life stress and semen quality.
The authors suggest that stress may affect semen quality via neuroendocrine factors influencing spermatogenesis. Increased levels of glucocorticoids, associated with stress may contribute to decreased rates of testosterone excretion from Leydig cells, responsible for spermatogenesis. Glucocorticoids may also induce apoptosis of Leydig cells, thus reducing the total number of cells, and thus, affecting male infertility.
Source: Fertil Steril, 2014 Aug;102(2):530-8. doi: 10.1016/j.fertnstert.2014.04.021. Epub 2014 May 23. Read more: Fertility and Sterility