Male fertility, strong association with manual labour

Physical tasks are associated with higher sperm concentrations

Men who regularly lifted heavy objects had higher sperm counts than those who did not. [사진=게티이미지뱅크]

Research has shown that physical activity at work can help men increase their reproductive potential. New research suggests that occupational factors, such as physical workload and work schedule, are associated with sperm concentration and serum testosterone.

A research team at Brigham and Women’s Hospital in Mass General Brigham in the United States found that men who regularly lifted heavy objects at work had higher sperm counts than those who did not. The study is part of the Environmental and Reproductive Health (EARTH) cohort of clinical studies examining how exposure to environmental chemicals and lifestyle choices affect reproductive health.

The researchers found that men who said they frequently lifted or moved heavy objects at work had a 46% higher sperm concentration and a 44% higher total sperm count than men who did less physical work. Men who reported more physical activity at work also had higher levels of the male hormone testosterone and the female hormone oestrogen.

Infertility is on the rise. Infertility can be caused by a number of complex factors, but it is estimated that around 40% of these are male factors such as sperm count, sperm quality and sexual function. In particular, sperm count and sperm quality are thought to be the main causes of more male infertility. An analysis led by the EARTH research team found that the sperm count and quality of men seeking fertility treatment fell by 42% between 2000 and 2017.

“We know that exercise is associated with a number of health benefits, including reproductive health, but few studies have been conducted on what occupational factors are,” said lead author Lydia Mingez-Alacon, a researcher. “Physical activity may be associated with significant improvements in male reproductive potential.”

“There is also increasing evidence that male infertility is associated with common chronic diseases, such as cardiovascular disease and autoimmune diseases, highlighting the importance of male reproductive health.”

The new study included some of these, including 377 men in couples seeking treatment at fertility centres.

“Reproductive health is important in its own right, but there is growing evidence that male infertility can provide insight into a wide range of public health issues, including the most common chronic disease,” said Mingez-Alacon. “Discovering possible measures will not only benefit couples who want to conceive, but society as a whole.”

The study was published in the Journal of Human Reproduction. The original title is ‘Occupational factors and markers of testicular function among men attending a fertility centre’.