VO2 Testing to Improve Fitness

As a Decatur Chiropractor focused on sports injuries, prevention and fitness, I am amazed at how how much triathlon training has changed in the past 10 years.  I remember the days when only the pros had tri-bikes and the amateurs were still riding aluminum frames. Today training for a sprint (the shortest distance triathlon) can require work 6 days a week. Running consists of long runs, speed workouts on the track and interval training.  A carbon fiber bike is the norm. In the pool, most competitors have joined a masters swim team and are doing intervals and speed sets in the pool. The training is much more sophisticated, even for the amateurs.

These training advances have resulted in a field that is fiercely competitive.  To remain competitive, many of you are familiar with and have incorporated target heart rate zones into your training.  You may own a GPS and/or a heart rate monitor.  These tools can help give you a ball-park value for which intensity zones you should be targeting during your workouts.

Unfortunately these devices and values can only create averages based on sex, age, and weight. Since they aren’t specific, they may actually prevent you from training as efficiently as you might desire. In this article I want to introduce you to the benefits of VO2 testing so you can see how this exact measurement can allow you to train even more efficiently and improve your performance.

In simplest terms, VO2 Max is the Volume of Oxygen the body consumes, or utilizes, in one minute of maximal exercise. VO2 Max testing, when done in a clinical or laboratory setting, gives you a value that is predictive of your fitness level and endurance ability.  It is the gold standard for fitness measurement and until recently, it was only available in a research or hospital setting.

During exercise, your body has multiple pathways to replenish the energy that is expended.  The most efficient method uses inhaled oxygen to convert glucose and fats into energy (adenosine triphosphate, or ATP).  The by-products of this process are CO2 and H20, which are very clean and can easily be removed from the body through breathing. As a result, training at a level that permits the body to remain in this state will allow the athlete to exercise for extremely long periods of time at a relatively slow pace. This is called aerobic respiration.

When exercise intensity increases, at some point the energy is consumed faster than it can be replaced through the aerobic system. At this point the anaerobic systems activate.  This “backup system” is less efficient, creates less energy (ATP) per cycle, and creates by-products such as lactic acid.  These by-products are the culprits that make it much more difficult and even painful to maintain high levels of intensity for long periods of time.

VO2 testing involves monitoring the changes that occur in the athletes body as the intensity of exercise is gradually increased.  The rate of oxygen consumed and the CO2 expired are precisely measured and recorded.  The athlete’s heart rate is measured and recorded as the exercise intensity increases.  Since there are various ways the tests can be administered, the athlete may chose the vehicle upon which they want to be tested. 

Most facilities will offer to test on:

  • Treadmill
  • Spin bike
  • The athlete’s own bike (on a trainer)

It is well understood that as the intensity of exercise increases, heart rate increases to compensate.  This response is the body’s attempt to pump additional oxygenated blood to the muscles and remove the CO2 and other by-products that are generated during muscle activity.  As intensity continues to increase, the body must incorporate anaerobic respiration to meet the additional energy requirements. 

During VO2 testing the same occurs. At some point during the test there will be a sudden spike in the levels of CO2 that are measured.  This is the point at which the body has reached the lactic threshold.  Lactic threshold is the point where the body is unable to remove the by-products of anaerobic respiration as fast as they are produced and they begin to accumulate.

The heart rate at which the athlete reaches lactic threshold is documented. For those only measuring the lactic threshold the test concludes at this point.  The athlete goes through a cool down period of two minutes during which their rate of recovery is measured.   

However if the athlete’s VO2 Max is being measured, the test continues.  Soon after lactic threshold is reached, the body will begin to have difficulty sustaining the gradually increasing intensity and the athlete will have to end the test.  This point is considered the athletes maximum VO2

Interestingly, maximum VO2 does not change with training.  However, the lactic threshold can be raised with specific types of training.  A higher lactic threshold allows the athlete to train more intensity and for longer periods of time. 

Ideally once an athlete has identified the heart rate at which they reach lactic threshold, and they know the rate at which they reach their maximum VO2, they can design a training program that will help improve their lactic threshold.  A higher lactic threshold means their body is more efficient at clearing out the products of anaerobic respiration so they can perform at a higher intensity longer and more comfortably.

For the serious triathlete it is recommended that the VO2 testing be performed at least twice during the season.  It is ideal to test early in the season, to make sure you know your heart zones that are most effective for training. Mid season is the other optimal time to have the test done to see if your training program is in fact improving your lactic threshold.  If for some reason it has not improved, then your training program should be altered to achieve the desired result. 

Accurately measuring fitness with VO2 testing will allow you to know your specific Heart Rate Training Zones for aerobic threshold, lactic threshold, and VO2 Maximum.  Armed with these facts, you and/or your coach will be able to design a training program that increases your endurance and speed, while decreasing your recovery time, injury risk, and ultimately giving you an edge on the competition. Our office owns a research grade machine that allows for extremely accurate test results. As athletes themselves, our doctors are highly qualified to help you interpret your results. Call 404-377-0011 for more info or to schedule your test.

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Dr. Niklaus DelFavero is one of the elite certified Georgia Sports Chiropractors with offices in Decatur and Johns Creeks.  His clinic, 1st Choice Sports Rehab Center features a multidisciplinary approach to rehab which includes physical therapy, chiropractic, and sports massage.  It has been named the Best Sports Rehab Center in the Southeast by Competitor Magazine and topped the 2015 list of Best Chiropractors by Kudzu.com.  They specialize in the treatment, rehab and prevention of sports injuries in athletes of all levels from beginners to elite and professional levels.  For more information or to schedule an appointment, call 404-377-0011.