Closely Related to: What is the latest evidence on underwear affecting sperm count?
Elevated temperatures are thought to decrease sperm counts in males.
Elevated temperatures impair sperm production and function. Although
studies are limited and are inconclusive, frequent use of saunas or
hot tubs may temporarily impair your sperm count.
Sitting for long periods, wearing tight clothing or working on a
laptop computer for long stretches of time also may increase the
temperature in your scrotum and may slightly reduce sperm production.
Keep your scrotum cool, because heat slows down the making of sperm.
To do this, avoid hot baths, wear boxers instead of briefs, and try
not to wear tight pants.
Researchers have found that the reason why a man's testicles rest
outside the body in the scrotum rather than in the abdomen like the
ovaries is because the ideal temperature for sperm production is three
to four degrees below normal body temperature. Any warmer will affect
sperm count, slashing it by about 40 percent per one-degree rise.
Temporary overheating of the testicles can result from exposure to
things such as saunas, hot tubs, heating blankets, even waterbeds.
So opinions vary on the accountability of research, but are consistent with heat having a possible risk.