Mental stress can take a toll on sperm and semen quality, affecting its fertility, a study by Columbia University's Mailman School of Public Health and Rutgers School of Public Health shows.
For the study, the researchers examined 193 men aged between 38 and 49. The participating men were enrolled in the Study of the Environment and Reproduction at the Kaiser Foundation Health Plan in Oakland, California, between 2005 and 2008.
The men were required to complete tests to measure work and life stress on a subjective scale (how they felt overall) and objective scale (life events behind the stress) and were told to submit semen samples.
The researchers found that mental stress lowered the quality of semen even after accounting for men's concerns about their fertility, their history of reproductive health problems or their other health issues.
The research team explained that stress at work was not a factor. But, it could still affect reproductive health as men with job strain had lowered levels of testosterone. Furthermore, men without any jobs had sperm of lower quality than employed men, no matter how stressed they were.
It remains unclear how stress affects semen, according to the researchers. It may activate the release of steroid hormones called glucocorticoids, which results in blunt levels of testosterone and sperm production. Oxidative stress can be another possibility behind the low quality sperm. It has been shown to affect semen quality and fertility.
"Men who feel stressed are more likely to have lower concentrations of sperm in their ejaculate, and the sperm they have are more likely to be misshapen or have impaired motility," senior author Pam Factor-Litvak, associate professor of Epidemiology at the Mailman School of Public Health said in a press release.
"These deficits could be associated with fertility problems," Factor-Litvak said.
"Stress has long been identified as having an influence on health. Our research suggests that men's reproductive health may also be affected by their social environment," said Teresa Janevic, the study's first author and an assistant professor at the Rutgers School of Public Health.
The study was published in the journal 'Fertility and Sterility'.