Ask Me Anything: Cardio Confusion

Dear Doug

Q:  When doing cardio I have been putting time in on the treadmill. I try to do at least 45 minutes or an hour on a progressive incline because I figure the longer I spend on the machine, the more calories I’ll burn. Someone suggested I’m wasting a good portion of that time and could actually get a more effective workout in a shorter amount of time by applying interval training techniques. Is this accurate? What is interval training? How does it work and I can apply to more than one type of exercise?

Cardio Confused-

A:  Thanks for your question.  First off interval training is performing cardio vascular exercise at various speeds, intensities and even environments (incline, decline etc.) during your session.  Compare 40 min. of treadmill running where the speed and the incline stay the same during the entire session (steady-state cardio) versus the same 40 min. of treadmill running where the speed and/or incline is changed frequently fast/slow and high/low during the session (interval training).  Both sessions were the same amount of time but chances are the interval training will seem much more difficult to complete because of the way it shifts your heart rate and the speed your muscles perform at.

Which is better to do?  I know I say this a lot but it depends on your goals.  If you are training to be the next Lance Armstrong then you have to put your time doing long duration cardio.  If you fall in under the blanket of “most of us” where you want to keep or build muscle and loose a little body fat then the long cardio bouts are probably not the best for you.

I use this analogy quite often; think of two types of runners, the 100m sprinter and the Marathon Runner; which one would you rather look like?  If you want the minimal muscle, skinny look then train more like a marathoner.  If you want more muscle then be more like a sprinter.  The sprinter never spends 30min. on a treadmill yet they have a ton of muscle and very low body fat.

Would you burn more calories and potentially more body fat if you just sat on a treadmill for 1 hour non-stop versus doing 5 x 60 meter sprints?  The answer is no and it is due to EPOC (Excess Post-exercise Oxygen Consumption).

Without getting too nerdy, EPOC is an increased rate of oxygen intake following strenuous activity intended to erase the body’s “oxygen debt.” Oxygen (EPOC) is used to restore the body to a resting state and adapt it to the exercise just performed. These restoration processes include: hormone balancing, replenishment of fuel stores, cellular repair, and anabolism (muscle growth).

During these restoration processes EPOC is accompanied by an elevated consumption of fuel.  After strenuous exercise, fat stores are broken down and free fatty acids (FFA) are released into the blood for fuel to aid in recovery.

In short, with interval training being more strenuous in a shorter amount of time, you may burn fewer calories during the workout but you will burn more fat AFTER the workout when the body is recovering.  If you want more muscle, less body fat, and you don’t need to run marathons; then interval training is the way to go.