Seahawks legend Marshawn Lynch may have hung up his cleats, but the Elevation Training Mask he made famous in pregame is still inspiring athletes who think it'll help them reap the same cardiovascular benefits as they would working up a sweat at 14,000 feet. (And, okay, it doesn't hurt that they get to look like a certain inmate at Arkham Asylum while they're doing it.) "They like the fact that it makes them look like Bane," says Shawn Arent, director of the Kinesiology and Applied Physiology graduate programs at Rutgers University, of athletes who come to school equipped with the mask.
Alex Viada, owner of Complete Human Performance, a training facility in Durham, North Carolina, also sees them on his trainees and their peers: "We've got some clients and coaches who do obstacle course races, Spartans, things like that, and I still see a lot of them around there."
Michael B. Jordan wore one last year in CREED, and Steelers running back DeAngelo Williams has posted pictures of himself training and warming up in a pink mask, pairing it with pink braids to look like a breast cancer awareness-spreading Predator.
Prolonged exposure to a high-altitude air, which has a lower concentration of oxygen when compared to air at lower altitudes, results in an increase in VO2 max, the body's ability to use oxygen. It also affects EPO, a hormone secreted from the kidneys that regulates red blood cell production. If you've heard "EPO" before, it's probably in relation to cycling and doping: Lance Armstrong's EPO injections were part of what got him banned from the sport for life. But hanging out at altitude can give you some of these red blood cell effects legally. More red blood cells means more oxygen carried to the muscles, which should translate to increased endurance.
But it's actually not from training at altitude that elite athletes increase EPO. Instead, they live at altitude, or spend long periods in low-oxygen environments to mimic altitude—like when British Olympian Mo Farah sleeps in a lower-oxygen tent. If the mask could mimic the lower concentration of oxygen of altitude, Viada says, it would actually be better for wearing to sleep than to the gym.
But here's the thing: "The adaptations you would get with altitude are not what you get with the mask," Arent says. "It doesn't increase red blood cell production. It doesn't increase your oxygen-carrying capacity." The mask doesn't actually lower the concentration of oxygen in the air, the way altitude does. It simply lowers the amount of air you can breathe. The mask feels kind of like training at altitude: By decreasing the volume of air you can breathe and by capturing expended air, making you re-breathe air that's richer in carbon dioxide, it makes exercise harder. The mask "does not appear to act as a simulator of altitude, but more like a respiratory muscle training device," according to a 2016 study.
Training Mask, one of the major manufacturers of these accessories, says it doesn't claim you'll get the systemic benefits of altitude by using its product. It claims that making your lungs stronger is the real reason to use the product. Wearing the mask has been shown to increase what's called ventilatory threshold, which is a measure of when your breathing gets too fast for your body to use the oxygen you're inhaling and exhaling.
"The essential point is that we think the importance of respiratory training is significantly overlooked in exercise science at present," the company said in an email. "Stamina and endurance are intimately tied to how well we can process oxygen during an activity. The best way to improve the availability of oxygen is to be able to breathe more powerfully and efficiently."
Studies of the masks have shown that the product does, in fact, strengthen the pulmonary muscles. But one such study, published in the Journal of Strength and Conditioning Research and provided by the company to substantiate its claims, concludes by saying "just because something can be used does not mean it should be … Clearly the training mask should not be adopted full-time. Reductions in sustained exercise tolerance and maximal exercise capacity would reduce training quality and negatively impact endurance exercise performance." That's right: Wearing a mask while exercising can reduce performance during a workout—by some estimates, by 20 percent.
The authors of that study suggest the mask be used "sometimes" as part of low-intensity training for collegiate endurance runners who are pounding the pavement for 10-15 hours per week—more than most recreational exercisers, who struggle to get 150 minutes per week. In other situations, Viada and Arent say, the reduction in training quality and performance could be a bigger detriment than the benefit of strengthening the lungs.
The jury's out on whether creating more stress on the pulmonary system is even a good thing at all. It may actually, in the long run, be detrimental—the more blood you're diverting to the pulmonary musculature, the less you're diverting to the skeletal muscle that's helping you move. "Whether [strengthening the diaphragm and pulmonary muscles] is a good thing is a big question, because the pulmonary system is rarely your limiting factor," Arent says. "At normal conditions, you tend to actually over-breathe at high intensities. We have a breathing reserve.
If you have to compete at altitude—say, you're a member of the Raiders preparing to go play the Broncos—this type of training would provide an advantage. Similarly, if you have to perform in situations where you can't get enough air, it would be beneficial: One study of firefighters found that training with the mask on helped them when they were wearing the full face masks they wear in an inferno, because those masks also impede their ability to breathe enough air. But if you're not Derek Carr or a member of the FDNY, it may just make your gym session harder. And, Viada says, just because something's harder doesn't mean it's better.
"Basically, it'd be like saying I want you to put tacks under your feet when you squat. It's going to hurt to squat a lot, but simply making an exercise more difficult for the sake of making it more difficult does not necessarily improve performance," Viada says. "In 99 percent of athletic activity, the feeling of shortness of breath is not that you're not getting enough air in your lungs. It's that your blood isn't getting enough oxygen to your working muscles, so you just feel like you can't breathe. It's got nothing to do with your breathing, though."
Wearing the training mask, in other words, is going to reduce your maximum exercise intensity. "It's going to reduce your pace. It's going to reduce the amount of time you can train. It's going to reduce all those other factors that are needed to make you a better athlete," Viada says.
If your goal is to increase the amount of oxygen your blood can deliver to your muscles, but you aren't able to invest in an altitude chamber and—we assume—don't want to dope with EPO, Arent suggests considering being tested for an iron deficiency: In his studies of biomarkers of college soccer players, iron levels fall over the course of a season. Supplementing iron, which is an important component of hemoglobin, can help the blood carry more oxygen, which might achieve a similar effect to having more red blood cells.
But the Rutgers scientist also says that instead of worrying about EPO levels, breathing, and altitude, most non-elite athletes would be "better off increasing the efficiency of the musculoskeletal system, so it can extract more oxygen off the air you carry in the first place," he says. We'll translate that for you: Get fitter.
Update 12/9/16: An earlier version of this story incorrectly described Marshawn Lynch's mask as "adorned with pot leaves and white knobs."