The difference between a sauna and a steam room can be summed up simply -- dry vs. wet. Saunas provide dry heat, while steam rooms generate moist heat. Both can open up your pores, loosen up your muscles and help you relax. Which one is right for you? It's mostly a matter of personal preference.
Dry or Steamy?
The dry heat of a traditional sauna starts with a heater that heats up a stack of rocks. Those rocks radiate heat into the room. In most saunas, you can pour water over the heated rocks to generate some steam and boost the humidity a bit --although nowhere near the level of a steam room. Saunas have a vent, usually found near the floor by the heater, that continually brings in fresh air and limits the humidity buildup. Some saunas, however, use infrared light rather than radiant heat.
Inside a steam room, a device called a steam generator boils water into steam and releases it into the air. Unlike a sauna, a steam room is nearly airtight, so the humidity builds to 100 percent. The air is so damp that water condenses on the walls.
Saunas Are Hotter
Saunas run considerably hotter than steam rooms, although because of the variance in humidity, your body may not sense the difference. A typical sauna will be set between 160 and 200 degrees Fahrenheit, with a humidity level of 5 percent to 30 percent. Steam rooms top out at about 110 to 120 degrees, but the 100 percent humidity keeps your sweat from evaporating, making you feel much hotter. Whether dry or wet, hot air always rises. In both saunas and steam rooms, the higher up you sit, the hotter you'll get.
Have a Seat
Saunas are built of wood for a reason; metal benches or tiled walls inside the searing heat of a sauna would burn you. Plus, wood absorbs moisture, which not only keeps the surfaces cooler but also helps pull humidity out of the air. In steam rooms, however, the high humidity and constant condensation would cause wood to degrade fairly quickly. Steam rooms are surfaced with non-porous materials, such as tile, that can get wet without causing problems. Self-contained units, such as those for home use, are often plastic. Steam rooms usually have sloped ceilings, so that water will run down to the walls rather than drip all over the occupants.
Relax and Destress
Steam rooms and saunas share some therapeutic benefits. Above all, they both reduce muscle tension, promoting relaxation and general well-being. The heat helps improve circulation and, of course, promotes sweating, which opens up the pores and cleanses the skin. Steam rooms may be more comfortable for people with allergies or congestion in the chest or sinuses. Saunas are the better choice for people with conditions that can be aggravated by humidity, such as rheumatoid arthritis.
No Magic Effects
There's no evidence to support claims that "heat baths," a catch-all term for both saunas and steam rooms, detoxify the body. The heat will open up your pores, which may help your skin, but it doesn't draw toxins out of your organs through the skin. Similarly, the ability of saunas and steam baths to help you lose weight is greatly overstated. Spend a significant length of time in either environment and you'll sweat enough to make a difference on the scale -- but the loss is all water weight. When you replenish your body's fluids, you'll be back where you started.