Results from a three-year study analyzing data from infertile men who had been repeatedly exposed to high water temperatures through hot tubs, Jacuzzis or hot baths are reported in the March-April 2007 issue of "International Braz J Urol," the official journal of the Brazilian Society of Urology. Study findings will be available online at www.brazjurol.com.br.
"It has been believed for decades that wet heat exposure is bad for fertility, as an old wives’ tale, but this effect has rarely been documented," said Paul J. Turek, MD, lead investigator who is a professor in the UCSF Department of Urology and director of the UCSF Male Reproductive Health Center. "We now have actual evidence to show patients that these recreational activities are a real risk factor for male infertility."
Although this was only a pilot study, Turek said, "these activities can be comfortably added to that list of lifestyle recommendations and ‘things to avoid’ as men attempt to conceive."
Dry heat exposure, for instance, as presented with fevers or through applied external heat, is a well-documented cause of impaired sperm production in both animals and humans, according to Turek. This is the first published study to show that total body exposure to wet heat can also impair both sperm production and motility. Study findings also showed that the negative effect of this exposure was reversible in nearly half of the infertile men who discontinued the practice.
An estimated 7 percent of American couples report that they are unable to conceive a child naturally within one year, according to the 2002 National Survey of Family Growth, the latest data available to the Centers for Disease Control and Prevention.
Of those, 30 percent are attributed to the male partner, 30 percent to the female and the remainder to either both partners or to unknown causes, according to the American Society for Reproductive Medicine.
The ASRM estimates that 85 percent to 90 percent of infertility cases can be effectively treated with drug therapy or surgical procedures. Less than 3 percent require advanced reproductive technologies, such as in vitro fertilization, but those techniques can be costly. The ASRM cites an average IVF cost of $12,400 per cycle in the United States.
"One implication of this work is that a simple lifestyle maneuver could ‘shift the care’ from high-tech intervention to low-tech or no-tech," Turek said. "Couples really prefer having kids at home and not with technology. This is a way to help them do that." Turek advises men who would like to conceive a child to "treat your body like a temple: Eat well, sleep well and take good care of yourself."
The study’s 11 patients were identified on the basis of repeated exposure to wet heat and were asked to cease that exposure for three or more months. Five of the patients (45 percent) responded favorably to the cessation of heat exposure and had a mean increase in total motile sperm counts of 491 percent after three to six months. This increase was largely driven by a statistically significant increase in sperm motility among responders, from a mean of 12 percent at the start of the study to 34 percent post-intervention.
Of the six patients who did not see an increase in sperm count or motility, tobacco use emerged as a possible differentiating factor. Five of those patients were chronic tobacco users with a significant smoking history, in contrast to only three occasional smokers in the responder group. No other potential gonadotoxic factors – harmful to the male gonad – were identified.
For the purposes of this study, wet heat exposure was defined as the immersion of the body in a hot tub, heated Jacuzzi or bath at a temperature warmer than body temperature for 30 minutes or more per week for at least three months prior to participation in the study. Patients were excluded from the study if they had received infertility treatments in the previous year, or if female infertility was a co-existing factor.
The only previously published study to examine this link was performed in 1965, according to the research paper. In that study, 20 men were exposed to direct scrotal wet heat for 30 minutes on six alternating days. The findings showed a temporary decline in sperm production during the treatments, but there were no details of semen quality before and after the study. An unpublished Swiss study in the 1940s had also linked wet heat to temporary male infertility.
Concern about wet heat effects on infertility crosses many cultures, Turek said, citing a centuries-old practice in Japan of barring childless men from conducting business deals in hot tubs, due to its believed effect on fertility.
Kristen Bole | EurekAlert!
Rutgers-led innovation could spur faster, cheaper, nano-based manufacturing
14.02.2018 | Rutgers University
New study from the University of Halle: How climate change alters plant growth
12.01.2018 | Martin-Luther-Universität Halle-Wittenberg
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.
But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...
Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.
The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...
Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters
Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...
Let’s say the armrest is broken in your vintage car. As things stand, you would need a lot of luck and persistence to find the right spare part. But in the world of Industrie 4.0 and production with batch sizes of one, you can simply scan the armrest and print it out. This is made possible by the first ever 3D scanner capable of working autonomously and in real time. The autonomous scanning system will be on display at the Hannover Messe Preview on February 6 and at the Hannover Messe proper from April 23 to 27, 2018 (Hall 6, Booth A30).
Part of the charm of vintage cars is that they stopped making them long ago, so it is special when you do see one out on the roads. If something breaks or...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
16.02.2018 | Information Technology
16.02.2018 | Health and Medicine
16.02.2018 | Physics and Astronomy