Eight weeks of HIIT increases both the number and efficiency of muscle mitochondria by expanding their energy-producing inner membranes.

Researchers from the University of Southern Denmark investigated how eight weeks of high-intensity interval training affect the structure of mitochondria—the parts of muscle cells that produce energy.

It involves running at a slower pace for a set period, then sprinting for another preset interval. One paper found that six sessions of sprint interval training improved the pace of seasoned athletes.

A new study suggests that HIIT workouts may help preserve lean mass in older adults compared to moderate exercise—but changes were small. Here's what to know.

High-intensity interval training, or HIIT, is a great way to torch calories, boost your metabolism and get a great workout in a shorter amount of time. And if you're a fan of hopping on the treadmill ...

Not all intervals are created equal, even if the average wattage is kept similar. Making intervals that vary in intensity can make them really different from constant wattage intervals. Tough short ...

High-intensity interval training, or HIIT, is the go-to workout modality for anyone who likes to get their heart rate up, strengthen their muscles, and then move on with their day. It focuses on quick ...

Every once in a while, I get a reminder that Twitter really can be useful. In this case, it was a tweet from Andy Jones pointing out an interesting detail in a new study that I might otherwise have ...