The science behind infrared saunas

The days of detoxing with a five-day juice cleanse are long gone.

Infrared saunas have been popping up across the country—like HigherDOSE, DTX Cellular Evolution, and Gravity in New York City and SaunaBar and sweatheory in Los Angeles—promising to help you burn calories, boost your mood, improve muscle relaxation, and more. Lady Gaga swears by the hot treatment to help with her chronic pain, Jennifer Aniston likes hitting the sauna after a workout, and others are addicted to the glowing skin a 30-minute session seems to elicit.

While all the claims behind infrared sauna as a miracle experience certainly don’t hold up, a surprising number of them do.

What Is an Infrared Sauna?

Traditional saunas (the kind with a stack of wood, charcoal, or stones steaming in the corner) use heat to warm the air, thereby warming your body from the outside in. Far-infrared saunas (FIRS), as they're technically called, use infrared light (that’s the one between visible light and radio waves on the electromagnetic spectrum) to create heat in your body from the inside out.

Because of this, one of the main perks is infrared saunas are not as hot as conventional rooms—around 120 to 150 degrees fahrenheit compared to the traditional 185 to 195 degrees. This makes the experience easier on your body, particularly for people who don’t tolerate heat well, while delivering similar benefits.

“Once you heat the body on a cellular level and bring up your core temperature, your heart rate increases, blood circulation increases, and more oxygen is delivered to the cells, muscles, and joints,” says Jourdan Rystrom, director of SaunaBar in Los Angeles. The idea is that with blood moving and sweat excreting, your body is releasing toxins at a high rate, confirms Svetlana Kogan, M.D., a holistic internist based in New York City who has been using infrared saunas in her practice for the past 15 years.

Rystrom recommends people hit FIRS for 30 to 40 minutes three times a week. There are many types of infrared saunas out there, though. Some use far-infrared light, some only near-infrared light (most people agree far-infrared is better); some keep your head outside, others enclose your whole body (which some may find uncomfortable for tolerating the heat); some saunas have you stand, while others have you sit or even lie down on top of jade stones, but it’s really a matter of preference.

What the Science Says

As soon as words like “toxins” start getting thrown around, it's wise to get a little skeptical. Here, the research and expert opinions on five common claims:

The claim:It will leave you with glowing skin.
The science: No studies support this one.
The expert opinion: Definitely holds up: “The healthy glow is from the opening of the blood vessels which makes the skin look more rosy, rather than pale or bluish which can look less healthy,” explains Zakia Rahman, MD, clinical associate professor of dermatology at Stanford University. Light reflects differently off your skin when the blood vessels are open, she explains. In fact, studies have shown people with flushed faces look healthier. “That is why we use blush as part of our makeup,” she adds.

The claim:It relieves post-workout muscle soreness.
The science:Spending time in a FIRS can help reduce aches and stiffness in people suffering from arthritis and alleviate chronic pain. For athletes, though, we only have one small study in SpringerPlus to consult, but it did find that the deep penetration of infrared heat, low temperature, and light humidity all made FIRS at least slightly beneficial for helping men relax and their muscles recover after endurance training.
The expert opinion: Rystrom says since FIRS increases blood circulation, it could help alleviate muscle soreness in athletes.

The claim: It’ll make you more fit and burn calories.
The science: The same small study in SpringerPlus found found sitting in a FIRS wasn't any more helpful in improving oxygen uptake, heart rate, or lactate concentration compared to endurance athletes who recovered without any sauna use at all.
The expert opinion: It probably won’t make you more fit or help you lose weight, but you are burning calories. You’re achieving the same increase in heart rate, circulation, and sweating as if you were in the gym doing moderate cardio for the same amount of time, says Kogan. While you are burning calories, most of the weight you’re actually losing, were you to weigh yourself right after, is water-weight, she adds.

The claim: It’ll give you energy.
The science:No studies support this one.
The expert opinion:Kogan says that in her clinical experience, FIRS are a great way to treat common fatigue in exhausted, but otherwise healthy, folks, since it improves circulation and cardiac output. Additionally, time in a FIRS might actually improve mitochondrial function, Rahman says. “Mitochondria are the engines of each of our cells and this infrared light provides them with extra energy.” Our mitochondria are similar in a way to the chloroplasts of plants, she says: They convert light energy to chemical energy. “Trees gain energy from light and our mitochondria do as well. This emerging field of light science is called photobiomodulation (PBM),” she explains. But every FIRS might not dose you with energy. Not only do different infrared saunas deliver light at various energies and wavelengths, but also the science of PBM is rather new, so we need more clinical studies to determine the best type of light to use and how long to use it to deliver the effect, she adds.

The bottom line:
Give it a try. Across the board, most experts and studies seem to conclude that using a far-infrared sauna certainly won’t hurt your recovery or health (unless you are pregnant, lactating, have unstable hypertension, or have an electric device like a pacemaker, in which case you should talk to your doc before trying it out).

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