NEW YORK (Reuters Health) - Male fertility plunges with frequent dips into the hot tub but may recover when men stay away from long hot soaks, research suggests.

"The lore in our culture is that hot baths are bad for fertility," Dr. Paul J. Turek told Reuters Health. "But I was seeing so many couples who had never heard this that I decided to look and see what was actually published on this topic."

To his surprise, said Turek, from the University of California, San Francisco, he found "scarce data exists on this subject to support the lore, and so we chose to study it in our own practice."

Turek and his colleagues identified 11 infertile men, average age 36, who habitually used a hot tub, heated Jacuzzi or hot bath for at least 30 minutes per week. The investigators evaluated the men's semen quality before and after they stopped using hot tubs, etc., for 3 or more months.

After 3 to 6 months, five of the men had an average increase in total motile sperm counts of 491 percent.

"A large chunk of men who regularly take hot baths, sit in hot tubs or Jacuzzi's can improve their semen quality and possibly their fertility potential by simply discontinuing this activity," Turek said.

Five of the six men who did not see an increase in sperm count or quality were chronic cigarette smokers with a significant smoking history, whereas three of the men who had a good response were only occasional smokers.

"The message for men trying to conceive," Turek concluded, "is to take great care of yourself and treat your body like a temple, as sperm production in particular is very sensitive to overall male health. It makes sense, given that a normal healthy man makes 1,200 sperm per heartbeat. This is a fast running engine that needs a healthy body to keep up that pace."