The Infrared Sauna Is Not a Weight Loss Tool

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In recent years, infrared saunas have become a hot wellness trend (Kendall Jenner even got one for her birthday, courtesy of the Kardashian sisters), reportedly offering a laundry list of benefits like “detoxification” (note: that's not a thing) and even weight loss.

Infrared saunas differ from regular saunas in that they aim to raise your body’s core temperature via light waves, whereas traditional saunas work by heating the room you’re in, says Nikki Ostrower, founder of Nao Wellness, a New York City wellness center that provides infrared sauna sessions. Her take (which aligns with most of the wellness industry's) is that as the body absorbs the infrared heat, it boosts your cardiovascular and lymphatic temperature. Theoretically, infrared saunas are meant to penetrate the skin and burn fat, heating you up so that your body has to work harder to cool off—which people have associated with weight loss.

“The idea is that [infrared saunas] can increase the metabolic demands of the body just by increasing temperature through these long infrared waves,” says Ian Nelligan, a primary care physician and clinical assistant professor in the department of medicine at Stanford University School of Medicine. “And the idea is that if you’re increasing metabolic demands, you’re going to burn more calories.

Nelligan says the effect is meant to simulate the benefits you’d get from, say, a power walk, but while resting in a nice sauna instead.

It’s unlikely that you’ll lose weight (save for maybe a little water weight) by sitting in any type of sauna. Infrared sauna spas point to one study from Binghamton University in New York that exposed people to an infrared sauna three times per week for 45 minutes, and found that after four months, those who used the sauna had up to a 4 percent drop in body fat compared to the control group, whose body fat did not change. However, the researchers did not control participants' exercise or diet outside of the experiment, making it hard to say for sure what really caused their weight loss. Nelligan says the evidence is shaky at best.

“If someone has really bad arthritis or chronic medical conditions that prevent them from being physically active, [these saunas] theoretically simulate the effects of exercise and help them be healthier through this technology,” he says. “But unfortunately, to the best of my knowledge, there are no studies that have actually validated that in humans, and so it’s not something that we can really recommend [for weight loss].”

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Though many claims about infrared saunas say that they target fat cells, Nelligan says the only weight you would lose really is water weight that you’re sweating out. Even then, that’s only a short term loss that goes away as soon as you hydrate. “Short-term weight loss [from infrared saunas] is very possible and almost entirely due to water loss,” says Brent A. Bauer, research director at Mayo Clinic Complementary and Integrative Medicine Program. “Long-term weight loss has yet to be proven.” This might be appealing if you'll be on the beach in a couple of days and want to drop a quick five, but it doesn't go much further than that.

"Some manufacturers claim that the infrared radiation ‘melts’ fat cells—but the evidence for this is nil," Bauer adds. Basically, if you want to try out an infrared sauna, you probably don’t have a lot to lose—and you might gain something in the way of relaxation, at the very least. But if you just want to lose weight, you might not want to put all your eggs in this basket.

There may not be any research proving that infrared saunas can aid weight loss, nor can doctors recommend them explicitly for that purpose, but that doesn’t mean saunas—infrared or not—are a complete sham. Ostrower says that people come into Nao Wellness for the "holistic benefits" these saunas can provide. “People who use traditional saunas long-term do appear to gain some health benefits, such as improved cardiovascular outcomes, ” Bauer says.

One small study published in Springer Plus suggested that the heat from infrared saunas can improve exercise recovery—so if the kickboxing class you took up has left you sore for days, sitting in a sauna could help you feel better. Plus, in a study published in JAMA Psychiatry, researchers looked at the effects of infrared light on mental health, with findings that suggested that exposing skin to the heat from infrared lamps could simulate the effect of antidepressants by stimulating serotonin production.

“There is a lot of evidence that traditional saunas can have a number of health benefits, and there is a smaller body of literature that suggests infrared saunas may also provide some modest health benefits,” Bauer says. “So we don’t want to throw the baby out with the bathwater."

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