The answer is as simple as you may expect.  Saunas operate by dry heat; however, water can be poured onto heated sauna stones or rocks to produce steam.  Once this has occurred the environment of the sauna changes from a dry heat to a humid environment.

Every person is going to handle the heat and humidity differently.  Typical saunas can reach around 190 degrees in temperature if turned all the way up.  People will build up a tolerance to the heat if they use their sauna frequently.  It is recommended that you stay in 10-15 minutes with a cool down break afterwards.  The general rule of thumb is that once staying in the sauna becomes difficult or uncomfortable it is a good idea to take a break.

We recommend for hygiene and personal enjoyment that you take a quick shower afterwards to remove residues and salts from your skin.  Taking a quick rinse will also help close back up your pores, it is a great way to finish your session.

For the average person there are no direct health concerns with a short sauna or hot tub session.  You should always consult a physician before you begin treating with these products if you are elderly, have a history of heart problems or high blood pressure.  Stay aware of your body and how you are reacting the temperature and the humidity.

Overall relaxation is by far the most reported health benefit.  Sauna owners can enjoy their session by sitting on a bench, lying down, meditating, stretching and even practicing yoga.  Because you sweat in a sauna it is also a great way to detoxify, relieve pain, and remove lactic acid in your muscles after a workout.

It really depends on the size of the sauna and what heating mechanism you are using.  In general, heated rocks and wood burning heaters take around 30-45 minutes to reach full temperature.  Other technical heaters such as electric or infrared heaters tend to have a shorter warm-up time and can reach full temperature in as little as 10 minutes.