HIIT stands for High Intensity Interval Training. It has become pretty popular these days because it is effective. Most people, when deciding they want to lose weight, jump on a treadmill or elliptical and go for a looooong time. There's nothing wrong with that, but it is not the most effective for fat loss. When you do regular cardio for an extended period of time, your body starts saving the fat for later energy, and will burn muscle. Muscle has a high calorie demand, so your body wants to get rid of that to save energy. Burning through muscle is the WORST thing because muscle boosts your metabolism! Usually, the lower your muscle mass is, the higher your body fat percentage increases, so we want muscle!
HIIT workouts are very short, but again they're effective! You get more out of a HIIT workout (as far as fat loss and boosting metabolism), then you would get from running on a treadmill for 60 minutes. Of course, I'm not saying long distance running, or types of endurance cardio, are bad! There is a time and a place for everything. But I'm talking about the BEST type of exercise for losing fat and getting the MOST out of the time you put in.
HIIT workouts are short intervals. There are many different types of HIIT workouts, but the ultimate goal is to get your heart rate up and reaaaally push yourself for a short period of time, and then have a recovery/rest period to let your heart rate come done a little bit. THEN you bring it right back up and repeat those intervals!
You can do this to a song by pushing it hard during the fast chorus, and bringing it down during the slower parts. You can do it a little more structured, like 20 seconds of hard work, 10 seconds rest. Or 30 seconds of hard work, 30 seconds rest. Or 40 seconds of hard work, 20 second rest. As long as you're switching back and forth, and pushing HARD during that intense part, you'll get the benefits!
You can do this with running (run/jog or jog/walk), swimming, bicycling, or with plyometric exercises such as burpees for 30 seconds, then taking a break, and repeating.
This is my favourite, FAVOURITE type of workout because, with a new baby, I don't have a lot of time to exercise. I do HIIT's for about 15-30 minutes, depending on how much time I have available. If I'm going to put in time to exercise, I want to make sure I'm getting the very most out of it!
You can easily make up your own and continually switch things up! If you're new to exercising, HIIT's are AWESOME! You can start with brisk walking for the "high intensity" part and slowly build your stamina to running for the "high intensity" part! HOLLA!