text: Sauna Science: At What Temperature Do Germs Die? – Scandia MFG
  Do Saunas Kill Germs?
  Most bacteria thrive at 40°F to 140 degrees°F, and dry saunas range from 176°F to 212°F with less than 20% humidity. This dry, oppressive environment is inhospitable for nearly all bacteria and viruses which thrive under cooler, more moist ecosystems. Infrared saunas are too cool (<130°F0) and steam rooms are equally cool and infinitely wet by comparison. Therefore, sauna bathing could be one of the cleanest spaces during an outbreak of a contagious illness.
  A whirlwind of scientific data backs various other health benefits from regular sauna usage. It holds particular power in illnesses that come naturally during aging, such as Alzheimer's and cardiovascular disease. Sauna bathing's ability to conquer some of these illnesses is due to its ability to stimulate the same response as moderate to vigorous exercise. Additionally, sauna bathing can strengthen the body's red blood cells, which boosts the immune system's ability to fight oncoming infection.
  Inside and out, sauna bathing is a safe and effective way to stem the tide of viral infection. Most medical research has proven that sauna bathing has a dose-dependent response to its health benefits. This means that more frequent sauna users experienced better results and reduced health risks, even more than their counterparts who used a sauna less often. Utilizing a local sauna or purchasing one for your own home might be the best investment you could make for your health.