1. Have you ever seen a fat jogger?
2. Have you ever seen a fat sprinter?
OK, now let's get into it.
We'll start with the obvious and not so obvious, move into the science and then finish with the practical. I'll also share my training program schedule with you.
The Obvious & Not So Obvious
Given an equal duration of time, the harder/faster you work the more calories you're going to burn. Even with the "rest" intervals of a sprint workout you're going to burn the same number of calories, if not more, as jogging. HOWEVER, you will burn a ton more calories AFTER the workout from the sprint workout. This is due to an effect called Post-Exercise Oxygen Consumption (EPOC), which essentially boosts your metabolism and fat burning ability for the next 24 - 48 hours - see The Science.
I actually talked about this in Monday's blog post - How to Train for Rapid Fat Loss & Fitness
In 1994, researchers for the Metabolism Journal discovered that each calorie you expend during high-intensity exercise (like sprints) burns nine times more fat than the same calorie expended during steady state aerobic exercise! HIIT accomplishes this in the following ways:
* Creates the Optimal Hormonal Environment for Fat Loss: HIIT puts your body in a "fight or flight" mode. As a result, your body releases certain hormones that directly mobilize stored fat to be burned off as energy during exercise.
* Burn a TON of calories both during and after exercise: Excess Post-exercise Oxygen Consumption (EPOC), otherwise known as post-workout "AFTER-BURN" is a measurably increased rate of oxygen intake after strenuous activity. This after-burn creates an elevated metabolic rate for 24-48 hours after exercise where fat is the primary fuel source. In other words, you burn more fat while you're resting!
* Increased glycogen storage: HIIT training rapidly reduces glycogen (stored sugar in the muscle cells) during training. With proper post-workout refueling your muscle cells "learn" to store more sugar, thus preventing that unwanted sugar-to-fat conversion. Carbs aren't the enemy when they have a place to go other than your butt and gut.
Many people, especially beginners, simply just aren't ready for the stresses (heart, muscles, joints, and even mental/emotional) that sprint work puts on their bodies. My suggestion for beginners is to start off slow and focus more on building an Aerobic Base. That may mean just walking for 20 - 30 minutes. Keep in mind that going from nothing to something will cause a positive change. From there, you may choose to make every other workout an interval training session where you jog for 30 - 60 seconds and then walk for 1 - 3 minutes for a total of 20 - 30 minutes. As you become more conditioned you can go from jogging to running to sprinting.
Here's what my program looks like:
Monday/Wednesday/Friday - HIIT Strength/Cardio (20-30 minutes*)
Tuesday/Thursday - HIIT Sprints (20-minutes*)
Saturday - Long Endurance Jog or Bike (1-hour jog or 1-2 hour bike*)
Sunday - Short Slow Jog (30 minutes*)
*I also do a 5-minute warm-up and a 5 - 20 minute flexibility program.
I hope that gives you a good understanding of what you should do for your cardio program.
Have Faith & Take Action! Justin Yule