A sauna is a small room or structure designed to provide a dry or wet heat session for relaxation and well-being. The term “normal” temperature is not fixed, as the heat level varies significantly depending on the technology used. Understanding the difference between traditional high-temperature air heating and modern lower-temperature radiant heat is essential to determine a safe and effective session. This knowledge allows users to appropriately select the environment that best fits their personal comfort and health goals.
Standard Temperatures in Traditional Saunas
Traditional Finnish saunas operate by heating the air to create an intense environment, typically achieving temperatures between 170°F and 195°F (76°C to 90°C). This high heat is generated by an electric or wood-fired stove that warms a pile of rocks. The resulting heat is primarily dry, with low ambient humidity, allowing the body’s natural cooling mechanism of sweat evaporation to function effectively despite the high temperature.
Many users prefer to keep the temperature near the middle of this range, generally between 150°F and 175°F, for an optimal balance of heat stress and comfort. The heat is often most concentrated near the ceiling, so sitting on lower benches offers a milder experience. A burst of humid heat, known as löyly, is created when water is thrown onto the hot rocks, temporarily spiking the perceived heat.
Temperature Differences in Infrared Saunas
Infrared saunas represent a different heating technology, operating at significantly lower ambient air temperatures than their traditional counterparts. The typical operating range for an infrared sauna is between 120°F and 150°F (49°C to 66°C).
Instead of heating the air, infrared heaters emit radiant light waves that are absorbed directly by the body’s surface and penetrate the tissues. This process raises the body’s core temperature from within, achieving similar therapeutic effects to a traditional sauna. The lower ambient temperature makes infrared saunas a comfortable alternative for people who find the high heat of traditional saunas overwhelming.
The Role of Humidity and Perceived Heat
The amount of moisture in the air is a factor in how hot a sauna or heat-therapy room feels, which is known as perceived heat. In a traditional dry sauna, the low humidity level, often between 5% and 20%, allows sweat to evaporate quickly. This rapid evaporation is an efficient cooling process for the body, enabling a person to tolerate the high air temperatures.
In contrast, a steam room operates at nearly 100% humidity with a much lower air temperature, typically around 110°F to 120°F (43°C to 49°C). The saturated air prevents sweat from evaporating, which blocks the body’s primary cooling mechanism. This lack of evaporative cooling means the lower temperature feels intensely hot and causes the core body temperature to rise more rapidly than in a dry sauna. Although often conflated, steam rooms are not saunas but illustrate how a lower temperature can feel much hotter due to high humidity.
Safe Usage Guidelines and Exposure Limits
Regardless of the sauna type, adhering to safe exposure limits is necessary for a beneficial experience. For beginners, sessions should start conservatively, typically lasting only 5 to 10 minutes, with gradual increases as tolerance improves. For most healthy adults, the optimal session duration is 15 to 20 minutes.
Maximum session duration should not exceed 30 minutes in high-heat traditional saunas, while the lower temperatures of infrared saunas may allow for slightly longer sessions. Proper hydration is necessary, requiring the intake of water before and after the session to replace fluids lost through sweating.
Individuals with certain conditions, such as recent heart attacks, low blood pressure, or pregnancy, should consult a doctor before using a sauna to ensure the heat exposure is safe.