Why Being Aerobically Fit Is Important for Building Muscle

When we try to build more muscle mass or get stronger, we tend to only focus on the lifting and hopefully the nutrition aspects.  However, the aerobic portion is important as well, and it often gets left behind when we plan our workouts.  Why is the aerobic, or our VO2 Max, important?  Well it all boils down to lactic acid…

When we lift weights, lactic acid is produced as a by-product of the anaerobic metabolism of glucose.  During anaerobic exercise, our body breaks down glucose into pyruvic acid, which is later converted into lactate and a hydrogen ion (together called lactic acid). In other words, we use glucose, a sugar, for energy when we lift weights with high intensity.  When glucose is being used, lactic acid is produced as a waste product, much like carbon dioxide is a waste product when we use oxygen for energy.  So, the body has to clear out the lactic acid in order for the muscle to keep functioning.

This is when the aerobic system comes in:  If sufficient oxygen is present, then pyruvic acid would have been consumed aerobically by the mitochondria within the muscle cells, producing even more ATP through the krebs cycle.  Furthermore, Lactate Threshold is when the rate at which the body produces lactate is greater than the body’s ability to clear it.  This is the onset of blood lactate accumulation (OBLA). (Since mitochondria chew through lactate oxidatively as fuel, L.T. improves with increased mitochondrial density, which is accomplished by high volume lifting.)

In a nutshell:

  • The more muscular you are, the more lactate you will produce.
  • the better your cardiovascular base, the faster you will be able to clear the lactate!

If you train your cardiovascular system regularly and try to increase your VO2 Max, then your lifting workouts might also experience benefits such as recovering faster between sets and more energy during high rep training.  If you keep up with your cardiovascular training, you might be able to get more out of your lifting sessions in less time.

information from http://www.ironmagazine.com/article403.html