date last edited 01/01/2006

What is VO2 max?

VO2 Max is the maximum amount of oxygen the body can take in and use per minute. VO2 max figures increase to a point with endurance training.

E.G. Lance Armstrong has a VO2 max value of about 84, top cross country skiers (very tough endurance event) are also around this value, sprinters have lower values 40-50. So endurance training increases the ability of the body to use oxygen efficiently.  More realistically my value when measured last summer was 64 and if you don’t know me, Eric’s at an educated guess will be around the same value.

What is Blood Lactate?

Blood lactate is lactic acid in the blood.  Lactic acid is found in the muscles and is a by-product of generating energy.  We all know the burning sensation when training (I hope) this is a build up of lactic acid.  More lactic acid is produced if the body is producing energy under anaerobic conditions (without oxygen) as opposed to aerobically (with oxygen).  Working at a low percentage of VO2 max sees most energy (but not all) produced aerobically.  As the work rate increases to a higher percentage of VO2 Max an increasing amount of energy (but not all) is produced anaerobically (without oxygen), which increases the amount of lactic acid being produced.  Lactic acid is removed and then broken down as fast as the body is able, so at a point the amount of lactic acid being produced becomes greater than the amount being broken down.  This is known as the anaerobic threshold (AT).  This point is at a higher percentage of VO2 max in well-trained endurance athletes.

E.G.:  Think of a bath, the plug-hole is empty, the tap (lactate production) is running slowly all the water drains out of the plug-hole (lactate removal). When water is going in at the same rate as it is leaving there is equilibrium.  If the tap is opened further there becomes a point when the water is going into the bath quicker than it is leaving, the bath fills up with water and eventually overflows (blood lactate production exceeds it’s removal so it accumulates).

Why are these important in racing?

The aim of racing is to perform just below your anaerobic threshold the point where you produce and remove lactate acid at the same rate, this would produce optimal performance.  Any faster and you produce too much lactate and you slow (the bath fills and overflows) any slower and you are under-performing.

Training at the right levels results in increasing the percentage of VO2 max at which AT occurs, your body can remove lactate quicker (the plug-hole becomes larger) and this means your body is allowed to go faster before the bath water begins to overflow.  The tap may run faster but as the plug-hole is also bigger and can remove the water quicker, this results in a quicker performance.

E.G.:  There are two athletes Andy and Eric.  Both have equal strength and have a VO2 max score of 64.  Andy can work at 70% of max before AT, Eric can work at 65% of max before AT, who is going to go faster?  (Ha Ha! But I hope you get the idea.  Working at the higher percentage will improve your performance).

How does this influence our training?

People who already train with a heart rate monitor will (should) train in zones.  E.G.: Easy 50-60% of Maximum heart rate (MHR) a recovery session. Steady 60-70% MHR, just under race pace.  Tempo 70%-75% MHR, a shorter, faster session.  Interval 75%-85% MHR, intermittent sprints with recovery.  Knowing the point at which AT occurs means a tempo session will be based at the heart rate which corresponds to this point.  Incorporating tempo sessions within your training results in your body getting used to removing the lactate quicker so you can work that bit harder before the burning sensation occurs and you slow.  Over a period this should in theory improve the percentage of VO2 max at which you can work and therefore performance.

I am already training using a heart rate monitor, what difference does this make?

Measuring blood lactate values will more accurately set the zones within which you should be training for your own body as opposed to using an approximated value for physical norms.

What do the tests involve?

The speed lactate test takes about twenty minutes (on a treadmill or a bike) with the speed increasing every three to four minutes, fingertip blood samples (similar to those taken by diabetics when testing blood sugar) are taken at the end of each period, just before the speed increases.  Samples of the air you breath out are taken during the last minute of each stage (by breathing into a tube).  Most people will not reach their maximum effort during this test but it will be quite hard work.

The VO2 Max test is a shorter test, but this time maximum effort is required.  Speed increases at the end of each three minutes stage until you think you can no longer go any faster, at which point you will be encouraged to continue for one more minute while the air you are breathing out is collected and analysed.  Some discomfort is felt at the end of the test but this is minimal and declines shortly after.  It is supposed to be a test measuring your maximum effort!!  Just think of it as that last effort towards the finish line.

What do we get as a result of the tests?

A full written report is given to you explaining the results and suggesting the optimal heart rates that you should train at.