Exposure to hot environments like saunas, hot tubs, and steam rooms can temporarily impair sperm quality and production, but the effects are typically reversible after stopping the heat exposure.
Here are the key points:
High temperatures (over 100°F/38°C) can cause scrotal hyperthermia, leading to decreased sperm count, motility, and increased sperm DNA damage.
Regular sauna use (e.g. twice a week for 3 months) has been shown to reduce sperm concentration and motility by over 50%, as well as alter sperm DNA integrity. However, these effects were reversed 6 months after stopping sauna exposure.
Even a single 20-minute sauna session can temporarily decrease sperm count, though it returns to normal within 5 weeks.
Hot tub use above 102°F (39°C) for 30 minutes per week for 3 months has been linked to impaired sperm production and increased sperm cell death.
The negative impacts on sperm quality from heat exposure are usually temporary, with parameters returning to baseline several months after discontinuing the heat source.
So in summary, while saunas, hot tubs and steam rooms can adversely affect sperm in the short-term, the effects are reversible once the heat exposure stops, making it a temporary impairment rather than permanent infertility.