what happens when you do HIIT

Get ready to burn! This video packs a punch, explaining what happens inside you during a HIIT workout. Heart pumping? We explain the body's response to intense exercise. Sugar rush? Discover how HIIT utilizes energy sources. Muscle burn? Learn how HIIT builds and repairs muscle. Plus: The secret to burning calories even after you stop and how HIIT can improve your overall fitness. Smash that subscribe button for more fitness breakdowns!