A good rule of thumb: you should not be able to talk and work out simultaneously during a well-programmed HIIT workout. Here's an example of a basic HIIT rowing workout. Total time: 12 min.

Another awesome workout in the books! Take the rest of the day to recover, and when you're ready to move on to Day 5 of the Women’s Health+ Ultimate HIIT Challenge, click below to access the ...

HIIT WORKOUTS DEMAND that you give your all. You might find that you have a hard time pushing to your limits on your own—so you'll get closer to achieving your goals when you have a world class ...