Fitness: Try a VO2 max and lactate threshold assessment

Credit: Gary M. Prior/Allsport
If youre an endurance athlete and ever wondered how fit you are, consider putting yourself to the test with a VO2 max and lactate threshold assessment.

According to Paul Kammermeier, M.S., exercise physiologist at the Boulder Center for Sports Medicine, nows a good time for cyclists and runners to test themselves in preparation for the upcoming season.

The VO2 and lactate threshold tests help endurance athletes assess how their bodies handle different exercise intensities the athletes can then use the test data to help set training program zones and intensities for the upcoming season.

As a cyclist with an eye on a few mountain bike races this season, I thought it would be helpful to see where I stood fitness-wise. Over the winter, Id been doing some snowshoeing and Nordic skiing, but mostly alpine skiing where gravity did much of the work.

I arrived at the Center dressed to ride and Kammermeier started out by preparing me for an EKG, placing sticky electrodes on my front and back where wires would attach.

When youre exerting yourself and we dont know your history (and sometimes you dont either) it helps us to monitor your heart rate throughout the tests for any irregularities, Kammermeier says.

He notes that in the past, the EKG and stress test found some abnormal heart rhythms in unsuspecting patients.

That detection can literally be a life-saver, he says

. I was also outfitted with a snug facemask that I would wear throughout both tests. While the mask made me feel a bit claustrophobic at first, I adjusted quickly once the air got flowing and I started to pedal.

I decided to take the tests on a stationary bike, but they can also be done on a treadmill. It just depends on your sport of choice.

We started with the lactate-threshold test, which is broken down into several three-minute stages during which heart rate and rate of perceived exertion are measured; Kammermeier then drew a few drops of blood at the end of each stage to measure my lactate levels.

As the intensity of each stage increased, Kammermeier asked me what my exertion level was on a scale from 1 to 10, and conducted readings from my blood samples to look for when my lactate took a big jump, i.e., my threshold.

So whats the significance of a threshold? Kammermeier explains that our bodies are always producing lactic acid and, in turn, always clearing it. But as we exercise more intensely, we produce an increasing amount of acid that does not clear as quickly and accumulates in the blood. The threshold is where the balance of producing and clearing falls apart.

A persons power output or speed at lactate threshold is one of the major determinants of endurance performance, he says, because it pinpoints the intensity which you can maintain for a certain amount of time.

Next up was the V02 max test, which is a measure of the fastest rate your body can consume oxygen to make energy. For this test, I established a comfortable RPM to pedal at and then tried to maintain it while Kammermeier gradually increased the intensity in one-minute intervals. For runners, this would be an increase in the speed and grade of the treadmill.

I pedaled for as long as I could endure while my oxygen intake was measured. The results would indicate my level of cardiorespiratory fitness and my potential for endurance performance.

V02 max is measured in milliliters of oxygen/kilogram/minute, or also liters/minute. Kammermeier says that runners are likely to be more concerned with the first method of measure due to the fact that running is a weight-bearing exercise thus ones body weight comes into play more. But both measures are provided in the final assessment.

Most elite endurance athletes range from 60-90 ml/kg/min while recreational athletes can vary from 40-60 ml/kg/min. Lactate, on the other hand, is measured in millimoles of lactate per liter of blood and theres no set range of levels due to the fact that were all different. The assessment also determines ones heart rate, running speed, and/or power output at LT.

Its important to realize that to improve endurance performance, you need to have variety in your training: long, slow distance, speed work, etc., Kammermeier notes. Moreover, the correct intensities for each type of training session are different between people. The tests we do determine the right intensity for each individual. Done correctly, the training will improve your speed at LT, as well as your efficiency and aerobic capacity (VO2max). These are the three major physiological determinants of endurance performance.

The higher a persons VO2max, the higher their potential to do well in endurance events.

The major limiting factor of V02 is genetics, Kammermeier explains. Usually it can be improved, but we all have a genetically pre-determined ceiling for VO2max.

While V02 is an important measure, Kammermeier notes that within a more homogenous group of people, its not the best predictor of performance as a single test. Thus its best to have both tests conducted.

I may have the same V02 max as you, but if I run a 6-minute mile in a 10K race while youre at a 6:30, its probably because I have a higher LT speed and am running with a more efficient stride. By the same token, if were running at the same pace, if it happens to be equal to your LT speed but below mine, the running will be easier for me than for you.

My numbers came out as I expected in the recreational athlete range for V02 and on the low end for LT due to my lack of endurance exercise over the winter.

So what can one do to improve? To increase your LT, one thing Kammermeier suggests is to do interval training at your LT heart rate combined with putting in a lot of miles.

A combination of endurance riding (or running) and speedwork at different intensities will help you psychologically and physiologically as you train, as well as recruit and train the muscles you need to ride or run longer and faster, he says.

Translation: faster speed through improved fitness and better efficiency.

If youre looking to enhance and measure your performance and training programs throughout the season, consider taking these tests two to three times.

The best time to take the tests is every 10-12 weeks during the season at stages where you feel youve adapted to your training load and could go higher, Kammermeier says. He notes that the tests should be taken during a period of rest or recovery.

So if youre looking to make some changes and improvements this season, and get a sense of where youre at fitness-wise, give these tests a try.

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