Answer to Question #10677 Submitted to "Ask the Experts"

Category: Lasers, Infrared, and Ultraviolet Radiation — Infrared

The following question was answered by an expert in the appropriate field:


Are there any harmful side effects of regular infrared sauna use?


The International Commission on Non-Ionizing Radiation Protection (ICNIRP) released a statement on Far Infrared Exposure in 2006. The ICNIRP statement on the biological effects of infrared radiation (IR) indicates that thermal injury (heat) is the dominant risk. Thermal (heat) injuries will depend on the wavelength (or color, if it could be seen) of the IR lights. IR light may cause thermal injury even if you do not feel pain for certain types of IR light exposure.

Hyperpigmentation, scaling, and telangiectasias (erythema ab igne) may occur from repeated IR exposures of elevated temperatures, even if the skin is not burned. Skin cancer is not expected from exposure to IR. However, increased skin temperature can reduce DNA repair efficiency, and promote skin cancer that is initiated by other agents. Skin thickness may also increase due to repeated IR exposures. Ultraviolet light is associated with photo aging of skin, and it is not specifically reported in association with IR light.

If the IR light is >1,500 nm, it is unlikely there will be any effects on the retina but damage to the cornea due to thermal heating could occur. The lens of the eye could possibly accrue damage due to elevated temperatures, leading to cataracts.

Additionally, one must be careful to not overcome the thermoregulatory mechanism of your body. It is possible to cause serious injury to a person by overheating when exposed to IR.

The ICNIRP does not address “IR saunas” but does address IR cabins. They note that there have been no reported cases of erythema ab igne from typical use, but cautions that there have been no controlled studies of saunas or IR cabins.

Overall, if the facility complies with ICNIRP limits, one would expect that no injuries would occur. The ICNIRP recommendations are rather complex to those unfamiliar with nonionizing radiation, and a person with expertise in this field should be consulted for compliance. 

Thomas E. Johnson, Associate Professor
Colorado State University

International Commission on Non-Ionizing Radiation Protection. ICNIRP statement on far infrared radiation exposure. Health Phys Journal 91(6):630-645; 2006.

Ask the Experts is posting answers using only SI (the International System of Units) in accordance with international practice. To convert these to traditional units we have prepared a conversion table. You can also view a diagram to help put the radiation information presented in this question and answer in perspective. Explanations of radiation terms can be found here.
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