We've seen some pretty questionable fitness trends out there, but the latest favorite among the likes of Selena Gomez and the Kardashian krew is one for the books. L.A.'s Shape House calls itself an "urban sweat lodge" which promises to get you a total body workout while you sweat it out to your latest Netfix obsession. Shape House claims that after an hour long session, you'll get the cardio equivalent of going on a 10-mile run, you'll burn anywhere from 800 to 1,600 calories, your body will detox as much as if you'd just run a marathon, and you'll also get tons of sleep, skin and endorphin benefits. (Related: Top 10 Celeb Workouts for a Killer Body)
Sounds great, right? The catch: You're not actually doing anything. Shape House cocoons you in a 160-degree blanket armed with detoxing infrared light and leaves you to sweat without moving a muscle.
If you think that sounds too good to be true, that's because it is. According to Edward Coyle, Ph.D., director of the Human Performance Laboratory at The University of Texas at Austin, the calorie-burning, marathon level-claims Sweat House makes are literally impossible. And the cardio claims are doubtful at best. Even if the heat does up your heart rate, the amount of blood your heart is pumping while you sweat it out to the new season of OITNB is only a quarter of what it would be if you were actually running, he says. (Other bogus ways to work out? These Exercises and Gym Machine to Skip.)
"Your body also doesn't improve its strength or muscular endurance this way," adds Noam Tamir, C.S.C.S, co-founder of TS Fitness in New York. "The heart rate goes up but it won't challenge your respiratory system or your VO2 max like a run will."
There are some benefits to simply sweating, though they're not on the level of the kind you get from actually exercising. Sweating does flush out your pores, and lounging while your body sweats out toxins can serve as a stress reliever. Think of it like the spa version of a desperately needed Netflix binge after a long week—but please don't think of it as a workout.
As for your heart health, it's true that overheating does get the blood pumping, but not enough to replace real exercise. "Boosts in blood volume and other factors can improve exercise performance, but this is typically in fitter populations who are training," says Matt Dixon, an exercise physiologist and head coach and CEO of purplepatch fitness. "It does not represent a similar set of physiological stressors that cause improved fitness and adaptations as developed through exercise."
Basically, sitting in a blanket in front of a TV is in no way a valid replacement for an actual workout. "There's no substitute for good eating and exercise, says Tamir. "Humans were made to move." Aside from the dubious calorie and cardio claims, simply sitting and sweating won't get you the balance, bone density, muscular skeletal, mobility and strength benefits you get from hitting the gym. You can watch Netflix however you like, but we're sorry to say sweat lodges won't be replacing your spin class anytime soon.