HIRT

Here's a quick way to build the type of muscle that is like the lean striated muscle of leopards not plumped up chicken breasts filled with water.
Your feelings don't matter! The higher the intensity, the less likely it is to feel "good." It's smart training and did we mention, your feelings don't matter.
You've heard that working out can boost your metabolism for hours, even days after. But what kind of workout has the biggest impact? And is it actually a good thing to do regularly?