One of the hottest pieces of sporting equipment this new year is a mask that makes you it harder to breathe. It's designed to simulate what it's like to exercise at a high altitude. And while it might make you look a little bit like Hannibal Lecter in "Silence of the Lambs," some users swear by it.
Justin Wesley says it enhances his workout. "You're sucking for air and it's not coming in because it's holding back the air," he told CBS News' Kris Van Cleave.
Manufacturers say the masks limit oxygen intake, strengthening lung capacity and building the diaphragm.
"You're going to take less breaths per minute but you're going to take breaths that count for more," said Michael Gennusa, the chief operating officer of Training Mask, which makes and sells the product.
Users can vary the intensity of their workouts by swapping out plastic disks to simulate different elevations. The disk for 3,000 feet has three holes in it to let in more oxygen, compared with the disk for 9,000 feet, which only has one hole.
Some professional athletes are using the masks during training to try to gain an edge in competition.
But does lower oxygen really equal a better workout?
Dr. Benjamin Levine of Texas Health Presbyterian Hospital Dallas specializes in exercise physiology and has studied the impact of high altitude training. He says that while it may have advantages for athletes who sprint a lot, for most people the mask likely does not provide signifiant health benefits.
"You're only spending a few minutes at altitude and that's not enough to induce any major productive changes," he said.
But Wesley says it's worked for him. After using the mask for 18 months, he says he's "shaved a minute off of my run time," and has lost 80 pounds.
The training masks sell for around $80 at sporting goods stores.