Common Fitness Mistakes #4. Cardio vs. Weight Training to Lose Fat
When it comes time to lose weight, what do most people think of?
If you said “cardio” and you pictured in your head a row of people slaving away on a treadmill, you are not alone.
Why is this? Hmm, that question may be too broad for single blog post. America’s fixation on running may have started after our victory in the marathon at the 1972 Olympics. It was further exacerbated in 1977 by The Complete Book of Running by Jim Fixx. This was widely influential in getting everyday Americans out in their jogging shoes. I will be the first to agree that increased physical activity is a good thing. But, I do have my preferences and if I was going to pick an activity that has the greatest overall health benefits, it would not be running.
By the way, it should be mentioned that Jim Fixx died of atherosclerosis at the age of 52! So maybe, just maybe, there is more to health then lacing up your tennis shoes and going for a jog.
The 1980s didn’t help much either. The science was building (not good science by the way) in the late 1970s that fat was bad for you. This thought process continued into the 80s and through much of the 1990s. And while the substitutions suggested by researchers were not all bad (more fruits, vegetables and whole grains) the only thing Americans heard was “Fat bad, Carbs good.”
Why does that matter? Because if fat is the enemy, we must attack it from all angles, whether we are talking dietary fat or adipose tissue. And one of those angles was cardio. The science demonstrates that during a typical cardio session you will burn more total calories and fat than a comparable amount of time spent lifting weights.
Ding, ding, ding! Knockout right? Let’s spend all of our time jogging on the treadmill.
Wrong, not so fast. It turns out that looking only at the period of time you are exercising was a case of not seeing the forest for the trees. If you zoom out and look at longer periods of time. Let’s say the entire day or time between exercise sessions, it turns out that weight training can burn MORE calories and fat than a low to moderate intensity cardio session.
Without boring you with all of the details, there are many biological processes and corresponding chemical reactions which are occurring in your body that require oxygen. During normal activity or even during a cardio session, you are providing the body with the oxygen it needs during the activity. You are maintaining the status quo so to speak, or homeostasis in scientific terms. However, during weight training (or high intensity interval training, but that is for another blog) you are getting into debt. How American!
Except this debt is an oxygen debt, known as excess post-exercise oxygen consumption, or EPOC. It’s a good debt! It is the amount of oxygen required to restore your body to its normal resting metabolic function. Without turning this into a science lecture, there are three main ways for your body to produce the energy you need to function. Aerobic respiration, anaerobic respiration, and a third way which is best left for another blog. All of these energy systems ultimately produce Adenosine triphosphate (ATP). ATP is your body’s fuel, or energy source. Cardio places more of a demand on the aerobic system while weight training places more demand on the anaerobic system.
The chemical pathways which the anaerobic system is utilizing to create energy without oxygen DURING the workout, interestingly, create a large demand for oxygen AFTER the workout.
Here is a list of the functions that require oxygen post workout for your body to recover: [1]
Production of ATP to replace the ATP used during the workout.
Resynthesis of muscle glycogen (your body’s stored carbohydrates) from lactate
Restore oxygen levels in venous blood, skeletal muscle blood and myoglobin
Work with protein for the repair of muscle tissue damaged tissue during the workout
Restore body temperature to resting levels
Added bonus! If you make weight training a priority over cardio during fat loss, you are giving your body the signal it needs to maintain muscle. Guess what your body wants to get rid of when you are in a caloric deficit? Muscle. Muscle is expensive to maintain, fat is not. Muscle helps keep up your resting metabolism which over time increases the amount of calories and fat you are burning.
What type of weight do you want to lose? Do you merely want the scale to drop or do you want to keep your muscle and lose body fat?
Assuming you want to keep the muscle and shed the fat, keep training with weights. Do not abandon the weights to become the next Forrest Gump.
Reference:
1. https://www.acefitness.org/education-and-resources/professional/expert-articles/5008/7-things-to-know-about-excess-post-exercise-oxygen-consumption-epoc
