Steam and hot rock saunas utilize the principle of Convection Heat. Convection heaters simply heat the air inside the sauna cabin and then the hot air heats the skin. Your kitchen oven is an example of a convection heater. Temperatures inside traditional saunas may reach 160 - 200 degrees Fahrenheit.
High air temperatures above 160 degrees Fahrenheit present a number of sauna user issues:
High air temperatures in sauna cabins are often overwhelming to the sauna user and produce an unpleasant experience. Many people report feeling lightheaded, claustrophobic, or experience difficulty breathing. In this muggy environment, the sauna user is neither comfortable nor fully relaxed.
Hot air convection heat overheats the surface of the skin and does not actually soak into the human body very deeply. Limited heat penetrates into the body severely limits the detoxification ability of steam and hot rock saunas; only a small percentage of your sweat actually contains expelled acids, toxins, carcinogens, and heavy metals.
Caution: High air temperatures in sauna cabins can be harmful to the viscous membrane tissue of your eyes, irritate nasal and throat passages, and cause rashes and itching in other skin sensitive body areas.
Also, the very high temperature used by traditional saunas can get to become very uncomfortable for people. The experience can then push your threshold and many users will not be able to reap all of the benefits of heat therapy because the air temperature has to get so high.
Heating: When it comes to heating a traditional sauna, you should allow anywhere from 30-40 minutes to achieve the desired temperature and to properly pre-heat the rocks. Of course, this heating time depends on the temperature from which the room is when you begin to heat the unit, also the amount of insulation in the walls of the unit, and the ventilation provided in the sauna. A well-constructed sauna will typically reach a temperature of 170-190º F in about 40-60 minutes.
The hot air heating technology in conventional saunas is rapidly becoming obsolete due to the lack of direct health benefits, oppressive user environment, and undesirable side effects...