men who regularly lift heavy objects at work or give weights in their day to day (without going too far) have a higher sperm count, which is one of the main indicators of the male fertility. This is suggested by a new study by researchers at Brigham and Women’s Hospital, an institution affiliated with Harvard.
It should be noted that 30% to 50% of men of childbearing age have a low quality semen, according to the World Health Organization. Toxics from the environment (plastics, pesticides, paints, detergents…), stress, being overweight, alcohol or tobacco are the main factors that deteriorate the quality of sperm.
The work, published in the prestigious magazine human reproductionis part of EARTH (Environment and Reproductive Health), a collaboration between the Harvard “TH Chan” School of Public Health and the Mass General Brigham Center that seeks to assess the effect of different environmental and lifestyle factors on fertility. The EARTH program has collected samples and survey data from more than 1,500 men and women. The current study also looked at a subset of these participants, which included 377 male partners seeking treatment at a fertility center.
The researchers discovered that men who reported lifting or moving heavy objects frequently at work had a sperm concentration a 46% older and a 44% higher total sperm count compared to those with less physical jobs. But there is one more finding in this research, which may come as a surprise: Men who reported being more physically active at work also had higher levels of the male sex hormone. (testosterone) and, contrary to what one might intuit, the female hormone (estrogen). And this, precisely, could explain the increased production of sperm.
“Contrary to what some remember from Biology class, the ‘male’ and ‘female’ hormones are found in both sexesbut in different amounts,” explains Lidia Mínguez-Alarcón, lead author of the study, a reproductive epidemiologist at Brigham’s Channing Division of Network Medicine and co-investigator at EARTH. The researchers hypothesize that physical exercise produces increased secretion of testosterone and the body converts the excess into estrogen to compensate for this imbalance in sex hormones. Put another way: “Excess testosterone is being converted into estrogen. Surprising as it may seem, this is a known way for the body to maintain normal levels of both hormones,” says Mínguez-Alarcón.
Infertility in men: what is the cause?
Male infertility is a growing problem, and can be caused by a wide variety of complex factors. However, around the 40% of infertility cases can be attributed to male factors. These are: sperm count, semen quality, and sexual function. In particular, the first two are believed to be the main drivers of the rising rates of infertility among men. An earlier analysis led by the EARTH study team found that, among men seeking fertility treatment, sperm count and quality decreased by up to 42%between 2000 and 2017.
While the current study found a relationship between physical activity and fertility in men seeking fertility treatment, more research will be needed to confirm whether these findings are valid for men in the general population. The researchers also hope that future studies will reveal the underlying biological mechanisms at play. “There is increasing evidence that male infertility is associated with common chronic diseases such as cardiovascular and autoimmune diseases, which highlights the general importance of male reproductive health,” says Mínguez-Alarcón. “Discovering practical steps people can take to improve their fertility benefits everyone, not just couples trying to conceive.”
How is it measured and how do you know if the sperm quality is good?
In approximately half of the couples who go to a reproduction clinic because they do not get pregnant, the infertility problem is the man’s. And in most cases, it happens as a result of poor semen or sperm quality. This is measured through a test called seminogram that analyzes these aspects:
- Semen volume: Normally, between 2 and 5 milliliters are produced per ejaculation. Bearing in mind that the number of ejaculations reduces the volume and this increases depending on the time of previous sexual abstinence, systematic values below and above those mentioned are indicative of problems that may affect fertility.
- Its viscosity: the way it thickens and then becomes liquid. Neither extreme means something good.
- Sperm concentration: normal is a concentration greater than 15 million spermatozoa per milliliter of sperm. The higher the concentration, the more likely the sperm to reach the egg to fertilize it.
- The amount of sperm: it is considered optimal that in each ejaculation about 39 million are expelled.
- The acidity: the pH and fructose content of the liquid are important. Citric acid and fructose indicate the secretory capacity of the prostate and seminal vesicles. Normal levels of both substances are above 52 and 13 micromoles, respectively.
- Its way: sperm morphology also matters. There must be at least 4% of them with a “normal” shape (taking into account head, neck and tail) so that they can fertilize the egg.
What can be done to improve semen quality?
As we have seen, semen quality can vary due to the influence of numerous factors. For this reason, on many occasions, doctors recommend repeating the semen study between 3 and 6 months after obtaining a poor spermiogram result. During this time, the physicians give instructions to the patient on healthy habits and recommendations you can follow to improve sperm quality.
Some of the most common advice is to follow a healthy diet. A diet rich in vegetables and fruit can help maintain healthy sperm parameters. The vitamins and antioxidants in these foods can help keep oxidative stress at bay, which damages sperm cells.
On the other hand, and as we have already seen, exercise or physical activity has been shown to be beneficial to improve the concentration and number of sperm in our body. First of all,
it keeps oxidative stress at low levels which is positive. In addition, it prevents obesity and therefore protects against diseases of the endocrine system. Paradoxically, intense physical exercise can produce the opposite effect: a drop in semen quality and an altered hormonal profile.
Finally, there are pills to improve sperm quality. These are vitamin-based food complexes and antioxidants that can help eliminate residues that cause oxidative stress and can impair semen quality. In any case, in this link you can read more recommendations to improve semen quality: How to improve my semen and its relationship with eating nuts.