"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." First author Lidia Mínguez-Alarcón, a reproductive epidemiologist in Brigham's Channing Division of Network Medicine and co-investigator of the EARTH study, said in a release.
The research comes from the Environment and Reproductive Health (EARTH) study, a collaboration between the Harvard T. Chan School of Public Health and Mass General Brigham. Researchers have collected data from more than 1,500 men and women, all with a focus on the effect of environment and lifestyle factors on fertility.
The data revealed men who lifted or moved heavy objects at work on a regular basis, had 46 percent higher sperm concentration and 44 percent higher total sperm count, than those with less physically demanding professions. The same group also were found to have higher levels of testosterone and estrogen.
Infertility has been a growing problem across the country, with about 40 percent of cases linked to male components, specifically "sperm count, semen quality and sexual function." What's more, there is substantial evidence that male infertility correlates with common chronic diseases such as autoimmune disease and cardiovascular disease.
“Reproductive health is important in its own right, but more and more evidence suggests that male infertility can give us insight into broader public health issues, including the most common chronic diseases,” said Mínguez-Alarcón. “Uncovering actionable steps people can take to improve their fertility stands to benefit all of us, not just couples trying to conceive.”