Physically Demanding Work Linked to Higher Male Fertility

A new study has been released with findings suggesting that males who often move heavy things at work may have greater sperm counts. The study was conducted by researchers at Brigham and Women’s Hospital.

The article, which was written as a part of the Environment and Reproductive Health (EARTH) cohort research and published in the Journal of Human Reproduction, focuses on the relationship between the environment and reproductive health.

The EARTH cohort is clinical research that aims to examine the influence on the reproductive health of environmental pollutants as well as the decisions people make about their lifestyles.

According to the data, it seems that the quality of sperm produced by men who engage in physical labor that involves heavy lifting is higher than that of those who do not engage in such work.

“We already know that exercise is associated with multiple health benefits in humans, including those observed on reproductive health, but few studies have looked at how occupational factors can contribute to these benefits,” said the author of the study Lidia Mínguez-Alarcon, a reproductive epidemiologist in Brigham’s Channing Division of Network Medicine and co-investigator of the EARTH study.

She further said, “What these new findings suggest is that physical activity during work may also be associated with significant improvement in men’s reproductive potential.”

Growing Concern of Infertility

According to experts, male factors account for about 40% of infertility cases, which may include sperm count, semen quality, and sexual function. Of these factors, sperm count and quality are believed to be the primary culprits behind the rising rates of male infertility.

In a previous study, the EARTH research team found that between 2000 and 2017, the sperm count and quality of men seeking fertility treatment declined by up to 42%. Therefore understanding the environmental and lifestyle factors that influence male reproductive health is of critical importance.

“Further, there is increasing evidence that male infertility is associated with common chronic diseases such as cardiovascular disease and autoimmune disease, highlighting the broader importance of male reproductive health,” said Lidia.

Study Design and Sampling

The EARTH study, a joint effort between the Harvard T. Chan School of Public Health and Mass General Brigham, aimed to investigate the impact of environmental and lifestyle factors on fertility.

The study has collected samples and survey data from over 1,500 men and women, with a particular focus on 377 male partners in couples seeking fertility treatment.

The recent findings from this subset of participants revealed that men who frequently lift or move heavy objects at work had a significantly higher sperm concentration and total sperm count, with a 46% and 44% increase respectively, compared to those in less physically demanding occupations.

Additionally, men with more physical jobs showed higher levels of testosterone and, surprisingly, estrogen, a female hormone. These results suggest that physical activity at work may positively impact male reproductive health, and further studies are required to understand the mechanisms behind these findings.

Further Studies

Although a recent study found a link between physical activity and fertility in men undergoing fertility treatment, further research is necessary to determine if these findings apply to the general population.

The research team hopes that future studies will elucidate the underlying biological processes behind the relationship between physical activity and male fertility.