Physically demanding work tied to higher male fertility, study suggests


Date:
February 22, 2023
Source:
Brigham and Women's Hospital
Summary:
A new study suggests that men who regularly lift heavy objects at
work have higher sperm counts.


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FULL STORY ==========================================================================
A new study from researchers from Brigham and Women's Hospital, a founding member of the Mass General Brigham healthcare system, suggests that men
who regularly lift heavy objects at work have higher sperm counts. The
study, published in Human Reproduction, is part of the Environment
and Reproductive Health (EARTH) cohort, a clinical study which aims to
explore how exposure to environmental chemicals and lifestyle choices
affect reproductive health.


==========================================================================
"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 first author Lidia Mi'nguez-Alarco'n, a
reproductive epidemiologist in Brigham's Channing Division of Network
Medicine and co-investigator of the EARTH study. "What these new findings suggest is that physical activity during work may also be associated with significant improvement in men's reproductive potential." Infertility is
a growing problem, and it can be caused by a wide variety of complex
factors. However, about 40% of infertility cases can be traced to male
factors, such as sperm count, semen quality and sexual function. In
particular, sperm count and semen quality are thought to be the major
drivers of growing infertility rates among males -- a previous analysis
led by the EARTH study team found that among men seeking fertility
treatment, sperm count and quality declined by as much as 42% between
2000 and 2017.

"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 Mi'nguez-Alarco'n.

The EARTH study is a collaboration between the Harvard T. Chan School
of Public Health and Mass General Brigham to evaluate the effect of
environment and lifestyle factors on fertility. EARTH has collected
samples and survey data from over 1,500 men and women, and the current
study focused on a subset of these participants, including 377 male
partners in couples seeking treatment at a fertility center.

The researchers found that men who reported often lifting or moving heavy objects at work had 46% higher sperm concentration and 44% higher total
sperm count compared to those with less physical jobs. Men who reported
more physical activity at work also had higher levels of the male sex
hormone testosterone and, counterintuitively, the female hormone estrogen.

"Contrary to what some people remember from biology class, 'male' and
'female' hormones are found in both sexes, but in different amounts,"
said Mi'nguez- Alarco'n. "In this case, we hypothesize that excess
testosterone is being converted into estrogen, which is a known way for
the body to keep normal levels of both hormones." While the current
study found a relationship between physical activity and fertility in men seeking fertility treatment, it will take further research to confirm
if these findings hold true for men from the general population. The researchers also hope that future studies will reveal the underlying
biological mechanisms at play.

"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 Mi'nguez-Alarco'n.

"Uncovering actionable steps people can take to improve their fertility
stands to benefit all of us, not just couples trying to conceive."
* RELATED_TOPICS
o Health_&_Medicine
# Fertility # Men's_Health # Prostate_Cancer #
Pregnancy_and_Childbirth # Fitness # Workplace_Health #
Diseases_and_Conditions # Women's_Health
* RELATED_TERMS
o Facial_rejuvenation o Heavy_metals o Fertility o
Molecular_biology o Somatic_cell o Inbreeding o Estrogen o
Functional_training

========================================================================== Story Source: Materials provided by Brigham_and_Women's_Hospital. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Lidia Mi'nguez-Alarco'n, Paige L Williams, Irene Souter, Jennifer
B Ford,
Ramy Abou Ghayda, Russ Hauser, Jorge E Chavarro. Occupational
factors and markers of testicular function among men attending a
fertility center.

Human Reproduction, 2023; DOI: 10.1093/humrep/dead027 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2023/02/230222141141.htm

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