Aerobic vs Anaerobic

by in Beachbody, Fitness June 15, 2011

I am often asked the question, “What is the difference between aerobic and anaerobic training?”  or “At what point does your body switch from aerobic to anaerobic metabolism?”  Well, the simple answer is aerobic means “with oxygen” and anaerobic means “without oxygen.” The point during exercise that your body switches from one system to the other depends on the individual; based mainly on genetics and the individual’s level of aerobic fitness.  However, if it were only that simple!  Let me try to break it down a little further….

Adenosine triphosphate (ATP) is the body’s main source of fuel, manufactured by the cells in our bodies.  Just like a car needs gas to get from your house to the gym; our body needs ATP to produce energy and function.  ATP is what enables you to walk into the gym and get on that elliptical machine! Our muscle cells produce and replenish ATP by using 3 separate pathways: the aerobic system, anaerobic glycolysis, and the creatine phosphate system.

At rest and for carrying out most daily activities, the cells in your body use oxygen (aerobic) to meet energy production needs. This is the way your body produces the ATP it needs to get out of bed in the morning, walk to the kitchen and make that first cup of coffee. The aerobic system is also the predominant system that allows most people to participate in a kickboxing class or go for a jog. That is until you are gasping for air and asking to take a break (i.e. – if you are doing Insanity)! At that point (which ranges from 50-85% max effort, again based on genetics and athletic level), your body no longer can supply the muscles with the oxygen they need, so it calls in the reinforcements to produce ATP quickly. 

As you bend over with your hands on your knees and gasp for air, your body has hit its respiratory threshold and is now relying on anaerobic glycolysis to replenish ATP quickly, so that your muscles continue to work for you.  The foods that we eat and subsequently use for energy are broken down into glucose molecules and delivered to our cells for use through the bloodstream.  Glycogen (multiple glucose units) is stored in our liver and muscles and can quickly be broken down into glucose for short-high intensity activities ranging from 1-3 minutes.  Consequently, when you are lifting weights or Tony Horton tells you to do tuck jumps for 30 seconds; this is anaerobic exercise. 

Anaerobic exercise is also what is going to give you that burn and may make it hard to sit down on the toilet the next day.  Sports like soccer, tennis and football all involve aerobic and anaerobic systems. Unlike aerobic exercise which produces water and CO₂, the end products of anaerobic exercise are heat, lactic acid and hydrogen.  Lactic acid is the lovely little compound in your muscles that causes the pain and discomfort after a hard workout.

It is very important that you include both forms of exercise in your workout regimen.  We have all heard about the benefits of aerobic exercise; including improved cardiovascular health, increase metabolism, and stress reduction.  Additionally, anaerobic exercise will improve endurance, strengthen & build lean muscle, increase bone density, and make aerobic exercise easier to perform.

Did you get a workout in today??? If it was all cardio, pick up the weights tomorrow!  Remember it is extremely important to “switch it up” for maximum workout benefits!!

 Fit Envy Training & Fitness

“Life’s most important investment is in you and your health!”