Mix It Up
Need to burn off a few holiday pounds? Keep your body guessing. A recent Japanese study found that resting for 20 minutes between two 30-minute workouts burns more fat than a straight 60-minute workout. And a College of New Jersey study found that mixing high- and low-intensity intervals into workouts speeds up post-exercise metabolism, compared with sessions done at an even pace.
Living at altitude is great for training but not for, say, having a job. But breathe through the portable AltoLab intermittently for an hour a day and your body will think it's at 20,000 feet. Testing on cyclists showed performance gains of 3 percent. $579; altolab-usa.com
The percentage of people worldwide carrying a recently discovered genetic mutation that predisposes them to excel at endurance sports, according to a recent Australian study in Nature Genetics. The 33,000-year-old mutation, most common in people of European or Asian descent, causes fast-twitch muscle fibers to behave like more efficient slow-twitch fibers—better for long hauls like Ice Age migrations or the Leadville 100.