Eavesdrop on the conversations of endurance athletes and the discussion will be all about VO2 max.
What is VO2 max? And how can you increase your VO2 max?
Firstly, VO2 max It is a measure of the maximum volume of oxygen that a person can use under intense exercise.
It is useful to measure because it gives an indication of a persons ability to provide essential fuel (oxygen) to working muscles, AND the efficiency with which the muscles use this fuel to create movement. It is basically how well a person utilises oxygen to create movement.
Better breathing is the key in endurance events to go faster and for longer.
In my last post I introduced the idea of oxygen consumption being an accurate measure of the amount of energy you expend, and therefore the number of calories you burn. What VO2 max does is basically put a value to this rate of energy expenditure. VO2 max represents the maximum value of energy expenditure you can reach at full-out effort. And it follows that the higher your VO2 max, the greater you oxygen consumption across all levels of effort.
What is a good value?
Lance Armstrong has been measured at 85 millilitres of oxygen per kilogram of body weight per minute. That's good. An average untrained person has a VO2 max of 40, and with years of training can get it to around 50 or 60.
Here are the values for some other athletes you might know (ml/kg/min):
Bjorn Daehlie, cross country skier: 90
Miguel Indurain, cyclist (winner of Tour de France): 88
John Ngugi, 5 times world cross country champ: 85
Dave Bedford, 10km World Record holder: 85
Sebastian Coe, middle distance (1 mile WR): 77
Just to put things in perspective, other VO2 max figures:
A typical thoroughbred horse can reach 180 ml/kg/min (consuming 600 litres of oxygen per minute!)
Sled-dog huskies have been recorded at 240 ml/kg/min! Quite incredible. That’s why these dogs can literally run all day – and through snow and in icy winds pulling a heavy load. 2 minute video of the view from a husky sled being pulled by 18 huskies at 30 km/hr.
Athletes have high VO2 max value.......horses have double........husky sled-dogs have three times the capacity
What is yours?
Using a simple 12 minute test - you can find out your VO2 max. Simply run as fast as you can for 12 minutes, and record the distance you have run. Convert that distance into VO2 max using the application on this website.
Can you increase your VO2 max?
When I was growing up my Mum said I could be anything I wanted. Which was very kind of her, but not exactly true. You see, try as I might, it's very unlikely I would ever be able to increase my VO2 max to a level that would make me competitive as a representative endurance athlete.
Why? It's not really something I can influence. Let me explain...
Firstly, here is the process of how oxygen is used for energy:
(Diagram courtesy of Prof. Frank Katch)
It is basically air in - oxygen enters blood stream via lungs - heart pumps blood (with oxygen) to muscles - muscles extract oxygen from blood to fuel mitochondria and create ATP for energy - waste blood (with CO2) goes back to lunges where CO2 gets exhaled.
VO2 max is determined by two factors:
1. The amount of oxygen you can deliver to your muscles from outside air (via your lungs and bloodstream)
2. The efficiency with which your individual muscle cells convert food plus oxygen into muscle energy (ATP)
Two steps then. Get the air in - and then use it as well as you can.
Top athletes therefore have a very good cardiovascular system for step 1, and then very well adapted oxidation capacity in their skeletal muscles.
Don't feel down if you don't have this - these abilities are determined genetically.
Of course, every single person on the planet is able to improve both of these two abilities. With basic training, you can increase your cardiovascular capacity and oxidative capacity....but there is a but…
Your rate of improvement will be much slower than that of the naturally gifted athlete. So try as I might, with all the training and effort in the world, it is unlikely I could have increased my genetically-typical initial attributes such that I would be competitive at endurance events.
And it’s not just me. If an adult male with initial VO2 max of 45 ml/min/kg trains consistently for 5 years, they could see their VO2 max climb to around 60-65 ml/min/kg. This is a huge improvement. Yet, the best athletes have a VO2 max of 75 to 85 ml/kg, so our hard training normal guy is still going to come up way short against the likes of these guys. And, if the athletes were to stop training for a year, their VO2 max might fall to about where the average guy’s topped out after years of training.
There is a big difference between these two guys...
The bottom line is that Olympic champions are born with unique genetic potential, AND potential to get much better. To be a champion they of course must realise that potential through years of training.
So what limits VO2 max? Can it keep increasing?
Again, it depends who you are:
For athletes, oxygen delivery limits VO2 max
Experiments have concluded that for athletes it's oxygen delivery, not oxygen utilization, that limits VO2 max.
By analysing one-leg exercises (to isolate a small muscle for measurement) and directly measuring muscle oxygen consumption it has been shown that the capacity of skeletal muscle to use oxygen more often exceeds the heart's capacity for delivery. It seems that in athletes the heart can't deliver as much blood as muscles can actually handle. The heart could provide as much blood as the muscle could use, but central blood pressure, and blood to the brain, would be compromised. Therefore, the solution for increasing VO2 max for athletes appears to be in the capacity and performance of their heart.
For non-athletes, skeletal muscle capacity is the limiting factor
Untrained individuals lack the oxygen-extraction ability in their muscles. Even if the delivery of oxygen is very high, the cells of untrained muscles have a lower oxygen consumption rate, and so often don't get to use all of the oxygen they are given. VO2 max tests on untrained persons illustrate this when the subject stops moving even while VO2 max readings are increasing: their muscles simply become fatigued too early - much sooner than their cardiovascular capacity is reached. In contrast, athletes can keep increasing their VO2 max right up until their heart rate peaks out. It's when your heart rate peaks out that you are at maximum effort - a place you can't stay for long.
Try the 12 minute test to see what your VO2 max is. And see how you compare with mean values for your age.
And for an even faster way to experience VO2 max, try a 1km sprint. Half-way through you may feel your aerobic capacity top-out as you reach your maximum oxygen capacity. It’s an interesting ride.