Why did you do this study?
Infertility among couples is typically associated with the female in the partnership, but men can also be a significant causal factor. Infertility rates in women have been gradually declining, but the male rates have remained stable or perhaps increased slightly in recent years.
The influence of exercise on male reproductive function and health has been a focus of my research group for several decades. The work of my graduate students and myself has resulted in the identification of the “Exercise-Hypogonadal Male Condition”; i.e., the male corollary to the athletic amenorrhea female condition (see earlier EXSS Impact Blog: https://uncexss.wordpress.com/2014/02/14/dr-anthony-hackney-exss-faculty-friday/).
The development of the Exercise-Hypogonadal Male Condition (EHMC) is associated with chronic suppression of testosterone levels. Testosterone has many physiological roles; one critical role is related to fertility. The key element of fertility status in the male is sperm quality and quantity, which are both negatively influenced in men with EHMC. But, another aspect of testosterone is how it influences behavior relative to sexual desire – that is, libido – and male libido obviously also affects fertility rates. It seems like a logical conclusion, men involved in lots of intense exercise training might have lower libido due to residual fatigue from such training. Logically this makes sense, but this topic had not been scientifically studied in a systematic fashion. Only antidotal reports exist in the literature, therefore our group decided to study the topic.
What did you do and what did you find in this study?
My graduate students, Colin O’Leary and Amy Lane, and I designed an online questionnaire-based study that assessed exercise training history components as well as male androgenic sexual attributes related to libido. We chose to focus on men involved with endurance exercise training – marathoners, triathletes, criterion cyclist … etc. – because of the greater prevalence of EHMC in these individuals. We contacted approximately 300 different organizations and groups associated with endurance activities as well as posted announcements in major sports magazine websites. We had several thousand respondents to the questionnaire. After removing individuals who did not meet our qualification criteria or had not fully completed the questionnaire we had about 1100 viable subjects’ response sets to analyze. With the help of Dr. Johna Register-Mihalik of EXSS on the statistical analysis and Dr. Diane Vaamonde (fertility specialist at University of Cordoba, Spain), we sorted through a massive amount of information.
From this data we found that the greater the training volume (eg, hours of exercise per week) and, the greater the degree of training intensity (moderate vs. strenuous activity) the more reduced the level of libido was. Depending upon specifically which training parameter we examined, endurance-trained men were 3 to 6 times lower in their level of libido than control subjects. These levels of decrease in libido are substantial, and previous published evidence points to this leading to reduced desire to engage in sexual acts. Libido is affected by many different things, physiological and psychological, and this was a questionnaire based study in which we asked about these confounding and mitigating factors. Obviously, we have to rely on the truthfulness of our subjects in this regard. We felt, however, due to the sensitive nature of the question material that was being asked about doing the questionnaire online and in a private setting (not in an interview fashion) might actually allow for an increased validity in our outcome responds by the subjects.
Interestingly, this reduction of libido does not seem to be an “acute” phenomenon where the man is just tired from the exercise sessions they did that day or the previous day. It appears it is a chronic and persistent reduction in libido, which is in agreement with the finding of chronic suppression of testosterone found in EHMC men.
How do these findings impact the public?
Any exercise training man and woman in a partnership and who are deciding to conceive and have children will need to recognize that male sexual desire is going to be impacted by the degree of training being performed. The couple needs to take into account the training volume by the man and share that information with their healthcare provider. Their provider may in turn want to make medical recommendations and suggest adjustments to the couple’s lifestyle that may improve the likelihood of conception.
These results inevitably cause people to wonder about women, exercise training and their libido. Substantially more research has been done in this area, but results thus far are contradictory and no current consensus exists on the impact. This is therefore, an area ready for further future research concerning exercise and the reproductive system.