How to Do HIIT Cardio
The two main types of cardio are steady state and high intensity interval training. The biggest difference between the two is during steady state cardio, your heart rate will increase to a certain point and then level out. During HIIT, your heart rate increases towards your max HR and then comes back down while resting between your high intervals.
I use both types of cardio depending on the scenario, client, goals, etc. I do prefer HIIT cardio because it has a lot of positive effects compared to steady state, the main one being it's shorter, but it's much more intense. When HIIT is done properly you will get the advantages of EPOC, excess post oxygen consumption, which basically means your body is trying to erase its 'oxygen deficit' that was caused by the intensity of the HIIT being ramped up so quickly. EPOC will keep your metabolic rate elevated throughout the day, which results in burning more calories and this can lead to greater fat loss.
The issue that I see when people do HIIT is the intensity is not nearly high enough to reap the benefits. Most people are doing intervals, not high intensity intervals.
How do you know the difference? If you are performing HIIT and your 'high' interval lasts longer than 20-30 seconds, your intensity isn't high enough. If you can talk when the interval is over your intensity isn't high enough. If you feel sick, you're doing them right. In my experience, a typical HIIT session lasts anywhere from 3-20 intervals. Obviously, this varies, depending on the goal, person, metabolism etc.
I will show an example of a HIIT interval in the video below. What we are doing here is trying to mimic a Wingate, which we use in the Exercise Physiology lab.
5 minute warm up on level 1 resistance.
Once the exercise bike's timer reaches 5 minutes, pedal as fast as possible aiming to get the RPM's to about 180 (no resistance).
Once that is reached,we increase the resistance drastically, and the client continues to pedal as fast and hard as possible for 15-30 seconds.
Once you finish, you drop the resistance back to level 1. Rest for 60-90 seconds and repeat.