What is VO2 max?
VO2 is the volume of oxygen measured over time and is typically expressed in ml/kg/min relative to body weight. VO2 max is the maximum amount of oxygen utilized by the body in one minute during exercise. It is one of many tests used to determine an athletes cardiovascular fitness and performance capacity.
VO2 was once considered the goal standard of measuring endurance performance until recently when measuring blood lactate became a better indicator. Other factors such as mechanical efficiency, anaerobic capacity and motivation can better be used to predict race performance.
There is typically a gradual decline in VO2 max of approx. 9% decrease per decade after the age of 25 in healthy but inactive people. A study by Jackson et al. (1995) found the average decrease was 0.46 ml/kg/min per year for men (1.2%) and 0.54 ml/kg/min for women (1.7%).
The American College Of Sports Medicine (ACSM) attributes these changes to lower maximal heart rate, lower stroke volume, lower contractility of the left ventricle, decreased vascular efficiency and alterations in muscle mitochondria. How much of this change is due strictly to age and how much is a product of lifestyle is not clear. However you can help to slow this process down with plenty of aerobic training each week.
The ACSM finds older adults to be just as responsive to training as younger adults, realizing a 10 to 30 percent improvement in VO2 Max in response to endurance exercise training. Losing weight is another way to increase your VO2 max along with plenty of training in the aerobic training zone working at higher percentages of your VO2 max (90-100%).
The highest VO2max recorded for a man was that of a champion Norwegian cross country skier who had a VO2max of 94ml/kg/min. The highest for a woman was 77ml/kg.min for a Russian cross country skier. Women typically have lower VO2max values than men due to their higher percentage of body fat, smaller muscle mass and weaker muscles. Someone who is deconditioned would have VO2 values below 30ml/kg/min to put things in perspective.
Figure 1. Normative values for VO2 depending on gender and age group. (ml/kg/min)
VO2 max can be improved with the correct type of training by as much as 60% but the average improvements after cardiovascular endurance type training vary between 5 and 15%. Studies have shown increases in VO2 max by more than 40% in normal sedentary individuals with very vigorous and/or prolonged training. These improvements are not influenced by age with the same increases in young and old. Genetics plays an important role in VO2max variations as much as 30-50% according to Bouchard et al (1998).
Altitude is another important factor affecting your VO2max due to a decrease in barometric pressure with increasing altitude which decreases the partial pressure of oxygen in the air, the lungs, and blood resulting in a decrease in blood oxygen saturation, cardiac output and VO2max. This is why some endurance athletes use the live high train low strategy to boost red blood cell production and increase the body’s ability to utilize and transport oxygen to the muscles. This increased oxygen levels can enhance the athletes endurance during training and competition.
Why should I get min tested?
If you want to know how efficient your body is at utilizing oxygen and are serious about dialing in your training zones then it’s worth getting yours measured in a lab. You will learn your aerobic and anaerobic zones and what heart rate and running velocity or power on the bike (wattage) that represents. You typically will get more accurate heart rate zones and learn your true max heart rate which is valuable if you use heart rate during training. If you are serious about training and improving your performance then it’s important to know your individual numbers so you can target weakpoints, dial in your training zones and train smarter.
Where can I get it tested?
Certain gyms, independent coaches, exercise physiology labs, sports medicine facilities, universities or hospitals. It is easier to measure if you are a runner or cyclist however it proves more difficult to measure accurately in other sports such as swimming or rowing. Recent developments in metabolic measurement technology allow portable devices to be used in the field rather than the confines of a lab however they are cost prohibitive for most people.
What does VO2 max testing involve?
Depending on your sport you can have it measured on the treadmill or on the bike using an indoor trainer specifically designed for this type of testing. You typically wear a mask connected to a metabolic measurement device to measure your oxygen consumption and calories burned during exercise.
Using a treadmill as an example for runners the test typically involves 4 to 5 submaximal stages between 3 or 4 minutes depending on the protocol and the level of athlete. The final stage is usually to exhaustion where the athlete will be running at or close to their top speed until exhaustion. There may be further increments in speed or elevation depending on the athletes performance and protocol.
A typical VO2 max test can take anywhere between 10-15 minutes or longer depending on performance. For cyclists they can use their own bike connected to an indoor trainer that allows the ability to control resistance (watts). Watts are increased each stage by different increments or so depending on the level of athlete until exhaustion.
What does VO2 max testing tell you?
It tells you the maximum amount of oxygen your body can utilize in 1 minute and you can compare the results to normative values of similar athletes in your age group. If you track your progress by getting a baseline test and retesting in 3 months after dialing in your training you should see improvements in VO2 values and be able to work at higher percentages of your max without fatigue. With certain metabolic devices you can also learn whether your body burns predominately fats or carbs and what heart rate/running velocity/cycling wattage that corresponds to. This will help you know how many calories to consume before and after training to ensure you are eating for sufficient energy demands. It’s more valuable if you get a baseline and retest throughout the season to ensure you are making improvements and targeting the correct energy systems.
Contact me if you have any questions about VO2 max testing for your individual needs or what you should do to prepare for a VO2 max test. I offer VO2 max and lactate testing for runners on the treadmill or for triathletes on your own road or tri bike using an indoor trainer.