There comes a time in every runner’s life when it’s time to kick things up a notch. That means one thing and one thing only: interval training. There’s a reason loads of runners don’t like intervals.

Want an exercise program that helps you work out smarter, not harder? You've found it. The Women's Health+ Ultimate HIIT Challenge is a week-long program that combines high intensity interval training ...

Here’s a graph showing the fraction of workout time spent at above 90 percent of max heart rate (black bars) and above 90 ...

Runners can easily fall into a basic routine for their workouts: Lace up, hit the pavement, then cruise at a comfortable pace for as many miles as planned. This might feel good, but it’s not always ...

A tool that can make run/walking even more effective, especially for athletes ready to get faster? The treadmill. Pairing ...

You’ve probably heard of HIIT—high-intensity interval training. You may even make a habit of doing the workouts yourself. And there are a lot of seriously impressive advantages of turning up the dial ...

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

In order to get faster, you have to practice running fast. Of course, this isn’t as simple as tackling all your miles at a higher pace. Instead, you need to incorporate running speed workouts into ...

Interval training doesn't always need to be complicated. Sure, it's cool to vary your rest ratios, or mix in a variety of equipment, or try an EMOM (every minute on the minute) or carefully build ...