What It Means to Be Anaerobic?

I subscribe to several of the popular fitness magazines just to keep up to date on what seem to be the popular trends in health and fitness, and I am often amazed at the amount of confusing information that there is in print pertaining to VO2 and heart rate topics.  Over the past several months, the words aerobic and anaerobic keep catching my eye so I thought I would address a few of the questions that I am often asked about these terms as painlessly as I can.

Before we go on, lets take a little side trip and talk about oxygen itself.  It is important to understand what the basic function of oxygen is in metabolism.  In short, as you breathe oxygen into your lungs, the oxygen is attached to a carrier (Hemoglobin) in your red blood cells that delivers it to the cells, making oxygen available for energy metabolism. 

Now that we have the oxygen basics out of the way, let’s get down to business.  Aerobic activity simply means “Involving or improving oxygen consumption by the body”:  i.e. aerobic exercise. Anaerobic exercise is defined as “Activity in which the body incurs an oxygen debt.”  To simplify this we can compare these terms to spending money.  Let’s say we spend less money than we are making each day; we could most likely sustain this type of spending for an indefinite period.  This would be aerobic spending.  Now let’s say that we spend more money than we are making each day and go into financial debt which we obviously cannot continue forever without complete financial failure.  This would be a fine example of anaerobic spending. 

In a nutshell, aerobic exercise is any activity that uses up oxygen and anaerobic exercise is reached when we just cannot supply enough oxygen to the system to meet the demands of the output we are trying to maintain.  So we are primarily aerobic much of the time until we increase our output to the degree that we require more oxygen then we can provide given the current level of conditioning and physical limits of our body.  When we perform in an anaerobic environment our breathing rate dramatically increases, we begin to feel the increased lactic acid, or “the burn”, in our muscles, and very frequently our bio-mechanics (form) during exercise rapidly deteriorates until we either finish the event or become incapable of maintaining the increased output and we slow or discontinue performance altogether.  Notice that I use the word primarily above as I will quite often.  There are very few absolutes in the human body and as long as we live, there are aerobic and anaerobic processes occurring simultaneously.  It would typically be an error to assume that our metabolism is ever in a constant state or that we could completely ignore or stop certain natural processes.

You might be asking yourself, “Why should we care whether we are aerobic or anaerobic. Isn’t any exercise good for me?”  While there are countless responses to this question, I will sum it up by saying that raising your anaerobic threshold is simply going to make your life easier, more efficient, and less stressful. 

That is a big statement I know, but let me try to explain what is happening inside that body of yours in as few words as possible.  Anaerobic threshold is the heart beats per minute point where you cross from primarily aerobic to an anaerobic state.  This again is achieved when the demand for oxygen in the system has exceeded that ability to supply it.  We simply cannot take in enough air to sustain our output and this creates a problem.  Your fatigue level begins to increase and the adrenaline and cortisol levels that lead to slower fat burning and the need for more recovery time rise dramatically while we are performing at sustained anaerobic levels.  Imagine for just a moment that you elevated you anaerobic threshold as little as 10 beats per minute; you would be more fit because you could work out harder and stay aerobic longer during that sustained acitivity. This would allow your body a much greater available output with much less stress on the system.  Going back to the shopping metaphor that we used above, you would be able to shop more often and spend more each time without going into debt at all.  Now doesn’t that sound wonderful to have more money to spend with less debt as a result!  The best part is that anaerobic threshold relates to our daily activities as well, walking up the same flight of steps at home would be easier on your system with less fatigue as a result. Walking down the street or sitting at your computer would both be less stressful chemically and even emotionally by simply elevating your anaerobic threshold.

The obvious question that remains is: How do I increase my anaerobic threshold?  This is the million dollar question whether you are an athlete or a homemaker.  I ask two questions of clients when designing a program with one of the end goals being the elevation of anaerobic threshold.  Note:  This is always one of the end goals.

1. Are you physically capable of safely entering into an exercise program?  This simply means are they a cardiac risk or do they have other considerations what would keep them from performing physical activity.   

2. Are you strong enough to embark on a cardiovascular fitness program?  I cannot emphasize enough that if your knees hurt or your back hurts or you develop various aches and pains from the most regular activities such as sitting, walking, running short distances, or standing, you do NOT want to be starting a cardiovascular program prior to beginning an isolated, linear resistance training program.  I meet more rehab. clients due to this error than almost any other.   

If the response to either of the questions above was no then it might serve you best to begin a very slow and consistent resistance training program which will increase your anaerobic threshold anyway and consult with your medical professional. 

If the response to both of these questions is yes, it is time to begin your quest for a higher anaerobic threshold.  The high point of this whole article is that developing a higher anaerobic threshold is often easier than the cardio program we are used to.  Begin with several weeks of training near but below your current anaerobic threshold.  This will train your body to be more efficient at the aerobic level and typically will begin to elevate your anaerobic threshold at the same time.  If you do not know what your current threshold is then utilize 180-age=BPM and use that figure as your heart rate during cardio vascular exercise for 4-6 weeks.  This is a rough figure but helpful for this type of training.  For most of us, this output level is much lower than we are capable of and that is the point.  If you are training primarily above your anaerobic threshold, it will slow your athletic progress after a time due to the chemical stress of training at that level.  You will progress faster by training for some time at a lower heart rate and sporadically utilizing sprint or lactate threshold training.  This is like cross training for your cardio and I think we all agree that cross training creates a better athlete and a stronger more capable body. 

The ability of a heart to maintain a lower rate while the body exerts a greater effort is one of the most important aspects of training.  Simply put, the daily stress on the human body during exercise and at rest can be greatly reduced by having a more efficient heart rate and a higher anaerobic threshold.  In the fitness world, information is the key to success.  I suggest that you find out what your anaerobic threshold is currently and work from there.  Do this by contacting a fitness facility or athletic department in your area to schedule a test. If you are local to us, then call us and we can schedule a test for you at our facility.  If you are not local and cannot find a facility near you, then write me and I will assist you with some less accurate but still beneficial testing that you can do yourself on a treadmill or stationary bike.