How valid is a VO2 test and results?

VO2 max: is the value of the total amount of oxygen used by the body at maximal intensity. It is the oxygen used by the muscle, heart, respiratory system and the brain. The maximum amount of oxygen that the body can use is expressed as a VO2 value.

Traditionally VO2 is used as an assessment for training intensities of which percentage of VO2 Max is most commonly used. Which is based on the VO2 Max and give a performance ability to compare against other athletes.

There are two ways in which we can view VO2 max.

• The typical traditional view: VO2 is the limiting factor to human performance, to improve VO2 max we need to train at or near VO2 max. 

• The alternative view: The weakness of either the cardiac system, the respiratory system or the muscular system will limit the VO2 performance. Finding the weakest link and training the weakest system will improve the efficiency of VO2. 

If we then view VO2 max from the alternative view, then to have the highest VO2, if simplified we require the respiratory system to collect oxygen and transfer it to the blood stream, extract the CO2 from the blood and transport it back to the outside world. The body requires a efficient cardiac system to pump the oxygen and CO2 around the body to and away from the muscle, and finally the muscles require mitochondria which loves oxygen for energy.

Sport where more muscle is involved will have a higher VO2, e.g. cross country skiing versus cycling, as there is a greater requirement for blood getting delivered around the body etc. Assuming technique does not hinder performance (as the extra muscle required to compensate for balance and coordination in technique require more energy) then the harder you go, the greater the requirement for oxygen and VO2 will go up. The faster you go the more you will push one of the limitations in your body which will limit you from reaching a higher VO2 performance.

A higher VO2 means your body requires more oxygen, but is a higher VO2 value always a good thing? Retesting for VO2 max where your VO2 has decreased for the same speed or wattage is often looked at negatively, rather it should be seen as a good thing as the lower VO2 at the same LBP is now more efficient so in theory you should be able to push longer with a more efficient system.

Some problems with VO2 tests:

There are various protocols developed to test VO2 max and each will give a different VO2 value for the same athlete. The problem is that if a VO2 test was truly physiological then you should get the same VO2 value every time for that sport. Some individuals during supra maximal test reached higher VO2 max result than during a standard incremental one (Hawkins et al).

With the VO2 test you are really only getting feed back on the respiratory system and the amount of oxygen that the body can use, and one variable of the cardiac system, i.e. heart rate. The entire test is based on VO2 and at what heart rate this occurs, in some VO2 test (that has been done on me) lactate was not even taken so you do not even have the metabolic feed back. The main problem with only having heart rate for the cardiac system is you have one variable and only know how fast the heart is beating, there is absolutely no information on stroke volume or cardiac output! Yes we could use formulas to calculate Cardiac output (VO2 Max= CO x (a-v) O2 difference), but most VO2 tests last 6 to 12 min and with such a short test time the intensity steps may be to big, too quick and in this case we could miss physiological markers. FeO2, CO2, Lactate, SpO2 etc all have a lag time of about 30 seconds, which means we will miss certain bio markers! Using a device like a physioflow which is non invasive gives you live feed back on hemodynamics and gives a fuller picture of the whole body’s reaction. With live hemodynamics we have information on Left Ventricle function,, Ventricular Ejection time, Stroke volume etc.

More practical and useful information can be gained from a VO2 test by looking at changing body position, RPM, stride length, breathing patterns to see if this changes the O2 and CO2 relationship. How many athletes know their breathing rate at LBP or even race pace? Or their breathing Tidal Volume? Why is this important? This information can be used to plan breathing training with a SpiroTiger to improve core stability, breathing coordination, diaphragm strength, and if you want to explore breathing training further even gas exchange.

A VO2 max test looks for a plateau to find the VO2 max value, Tim Noakes, 2008, demonstrated that in most test this plateau does not occur. Knowing when a test will end, i.e., the length of the test also will effect the outcome value (Baden et al). The first time I do a new fitness test is always the hardest, (e.g. a 60 second jumps test measuring sustained power) because I don’t know what to expect, in a follow up test I know how to pace so I have changed the results with out likely actually really improving). Lactate threshold can be completely missed, probably overestimated during a VO2 max (even standard Lactate test the so called anaerobic point is over estimated in most cases). Athletes training at the same percentage of VO2 max with similar VO2 max values can have huge variants in training outcomes (Scharhag-Rosenberger et al). The entire VO2max protocol needs to be reviewed.

Once again with a training program where training zones are based on VO2 max percentages, we do not have a clue what we are training. What is the cardiac system doing? what system in the body are we stressing? At what point is the Left Ventricle function being challenged which will affect stroke volume? With out looking at the body as a whole we do not have a clue. Rethinking the VO2 protocol to follow physiological reactions would be one step in the right direction. A Lactate Balance Point or Zone test (LBP developed by FaCT) with lactate for metabolic changes combined with VO2 for pulmonary information and cardiac feed back on hemodynamics gives more information than a VO2 max test EVER will. Unfortunately our coaches and physiologist are traditionalist and follow what they were taught in University and these ideas will take time to be accepted until they look at how we can train the body as a whole and instead of training speed, power, endurance rather think train muscle, cardiac, respiratory and how these system react during speed, power, endurance and when they fatigue so that we understand how much overreaching is required.

The LBP idea and testing using respiratory and hemodynmic devices is part of FaCT's continued research. FaCT Canada is actively engaged in researching and continuously testing more reliable ways of assessing the body, currently they are looking how CO2 can be used as a biomarker by using a capnometer. To read more in depth discussions go to their site at FaCT. There is a in depth article on The Fallacy of Vo2max and %VO2max on the site Science of Running.

Drifting slightly off the VO2 subject, this is simply me thinking loud. We often wonder why we get different outcomes with research studies on training ideas and altitude training (or even VO2 training zones) etc where we have responders and non responders to the training load. If research really wanted to have a controlled group, they could simply do a full assessment where they find which people in a control group have what limitation. And when at the end of a study they have there responders and non responders they will more likely have a clearer picture of why certain subjects responded in certain ways because they were limited by there cardiac system or ability for muscle to utilize the fuel given to it etc. At least this is how I would do a controlled physiological study.

Lactate Balance Point – LBP

The majority of physiologist and athletes reading this article will think these ideas are crazy, if you think so come back in 10 or 15 years and read these ideas again. Read this article and the links, understand why, and you may have found a better tool for threshold testing.

DIFFERENCES BETWEEN A LT TEST AND LBP TEST: 

At first it may look similar to a normal Lactate Threshold (LT) test, ventilatory test or anaerobic threshold. But it is different. LBP is a assessment for fitness training levels. The LBP is simply lactate in balance at a certain level, there is no increase in the lactate level and no decrease. It is the area where the body if the ECGM (CGM) is correct reaches its weakest point. LBP, originally developed over 20 years ago has been researched and field tested over the last several years by FaCT with hundreds of repeatable results.

The LBP assessment is different, in that the bodies Lactate Balance Point is more easily and accurately found than using traditional sometimes misinterpreted Threshold Tests.

Diet influence on traditional LT test

Diet influence on LBP test

We need to look at lactate as a bio marker of fatigue and an indicator of energy stores. Lactate is highly influenced by what you eat, as lactate responds to glucose which will affect lactate levels. The LBP assesment is hardly affected by what is eaten but glycogen stores can mess up the traditional LT step test curve. This can be proven completing a traditional LT test carbo loaded and then repeated being carbo depleted (protein loaded). So the theory that (Mader) 4 mmol is anaerobic threshold is blown out of the water with this in mind. It would be like saying every person has a max heart rate of 220 minus their age. So looking for 4 mmol will not be accurate as there are other factors involved. Just because you had x mmol of lactate at x heart rate in a test does not mean that x mmol will always indicate threshold. 

The traditional LT test is based on a objective protocol based upon wattage normally 20 watt step increases, for some people 20 watts is to much at some point which will lead to a too big jump in heart rate which will mean a large part of the heart rate range may be missed, this big jump will also lead to a 'jump' in lactate which will falsely indicate threshold. Lactate is always present in the human body even at rest and will increase linear as heart rate increase (Connet et al circa 1984). The LBP assessment follows physiological parameters where heart rate is increases by 5 to 10 beat and the balance point is not missed. LBP will normally be lower than what you get from a LT test and this is because LBP test give you the point of the weakest link, with a LT test you are getting the point where the test has overstepped the bodies (weakest point) limit and the bodies ability to handle the metabolic process in the muscle.

Anaerobic threshold does not exist! There is no proof or evidence that muscle would go anaerobic during intense or max workouts. Research is showing that oxygen may actually be higher during all out exercise than lower intensity’s (Connett, Gayeski, Saltin). Lactate is used as a fuel and may especially at higher intensity be a preferred fuel source (Brooks and Dubouchaud).

The above were some of the reasons for the development of the Lactate Balance Point assessment.

THE LBP ASSESSMENT:

A brief explanation of the test. The body is warmed up gradually with a step increase of 10 to 20 watts every 3 minutes upto a perceived exertion (Pe) of 7 to 8 (about 15 min). No lactate is taken during the step test, only at the end of the 3 min where Pe 7/8 is found, SpO2 is also taken (oxymeter). This is the only part that resembles a traditional step test and is only done to warm the body up and get lactate raised, ready for the actual assessment. There is absolutely no need to take lactate before Pe 7/8 or any need to take the athlete to max which will tell you nothing about his LBP (or threshold if you really wanted to call it that).

Now drop the wattage by 50% and continue without rest. This is where protocol stops and physiology reaction assessment starts. Take lactate and SpO2 after 3 min at 50% wattage, continue at 50% until you have the lactate reading and decide if or how fast the lactate and heart rate has dropped from the Pe 8 reading, whether to continue on 50% for another minute.

LBP test with LBP at 155 bpm

If there was a big drop go to the next step immediately if a slow drop in lactate and heart rate stay another minute. To go to the next step increase wattage until HEART RATE increases by 5 to 10 beats, after 3 minutes take lactate and SpO2 again stay at the current HR and wait for the Lactate result, if not dropping wait another minute if lactate is dropping increase HR by 5 to 10 beat again, continue this until lactate stops dropping and there is a increase in lactate. When there is a increase you have your balance point.

Using this method less lactate strips are used. (to know how much to increase wattage for the 5 to 10 beat increase use the initial step test to Pe 8 as a guide on wattage/hr increases). What a lot of coaches and physiologist find hard to accept with this test is that there is no protocol, that steps can be be prolonged, and that the test follows physiological parameters, we have to look at how the body reacts and have to think during the test. Read the articles on FaCT test system and what is LBP test.

Instead of wattage perceived exertion or speed can be used as a guide for increasing HR.  The SpO2 reading is used to get information on the blood situation and can be used as a guide for finding LBP in combination with lactate. This is the basic assessment to find the LBP, for zoning a later article will be written.

Latest in fancy kit vs testing. Part 2

(This follows from Latest in fancy kit vs testing. Part 1) Testing is seen as a way to assess how good a athlete has become. If any improvements have been made, to see how long and hard a athlete can push themselves.  We are told we pushed a bigger wattage, we have a better power to weight ratio, we have reached a higher max heart rate, we need to improve on lactate threshold. Would it not be better to look at fitness testing to find a athletes weakest link in the trainable system (Physiology from a different angle) and if the weakest link has become stronger? Thus looking at the individual systems in the body.  To do this we have to change the philosophy, that power and speed and time are objective tools to see a result towards the physiology, that individual physiological reactions are the tool for success.

This idea and the tools used with it will be in another 10 - 15 years time when it is hopefully better accepted by Sport Science in general. We now have great physiological testing tools, NIRS, PhisioFlow, Polar Heart Rate Monitors, Suunto Heart Rate Monitors that give information on EPOC and BioHarness which measures through a heart rate strap body temperature, breathing rate, ECG and pulse. But due to the development of flashy and high tech gadgets like SRM (which undeniably has had its successes) we are taking a step backwards from physiological information. We have rowing machines and spinning bikes that have wattage information and everybody is pushing for a target wattage and forgets to listen to the bodies response. We have new training devices like the SpiroTiger which is a brilliant training tool when used correctly but due to our own competitiveness we will try to push the biggest bag size and breathing frequency with only short term if little improvement.

We have to wait until people can see and understand physiology from a different angle and that absolute values and graphs are great tools but give limited information for the deeper assessment to the working body.

Latest in fancy kit vs testing. Part 1

This article and much of this blog is inspired by the forward thinking of FaCT Canada. 


Look at any one of the recent Olympics or World Championships for most sports, and one will see the amount of money spent on sport equipment rather than the athlete centered ideas.  Agreeably some equipment is essential but I am talking more about the latest in aerodynamic helmets, swimsuits, clothing design because image is everything.  Or we see professional cycling teams with bigger budgets than some low key Olympic sports that spends huge sums of money on doctors and drugs (this is a generalisation) i.e. the Festina afair 1998.

But then one sees these same things in general public sport where we see riders rather buy the latest deep section aero wheels to be faster (modern bicycles and cycling speeds, any relation? ), rather than get properly assessed and tested so that they can have real performance improvements by searching for the weakest link and looking for bio-markers.

Swimming is a example that has not changed a lot in the way we coach and train athletes. Despite the fact that we have Heart Rate monitors now for water use (Hosand) and even intramuscular Oxygenation testing (NIRS), we still plan programs on amounts of fingers on your hand and length of the pool and turns on a clock. 

Have a think about it.


Latest in fancy kit vs testing part 2