VO2 Max & Blood Lactate

VO₂ max refers to how much oxygen your body can absorb and use during exercise 

When we exercise, we must have oxygen

​VO2 max is a popular testing measurement for athletes

​VO2 Max is the most accurate measure of cardio-respiratory fitness

Your VO2 Max decreases the less oxygen available to consume at higher altitudes

The greater your VO₂ max, the more oxygen your body can consume, and the more effectively your body can use that oxygen to generate the maximum amount of ATP energy. 

VO2 max is the maximum amount of oxygen the body can utilize during exercise. 

It's a combination of how much oxygen-rich blood your heart can pump, and the heart's efficiency in extracting and utilizing oxygen. 

Your VO2 max is made up of three main components:

• Lung capacity & heart volume. The greater your lung capacity, the more oxygenated blood your heart can pump, and the higher your VO2Max score.
• Capillary delivery. The more oxygenated blood that can reach your muscles, the higher your aerobic fitness score.
• Muscle efficiency. The better your muscles are at utilizing oxygen from your blood, the better your VO2 max reading.

How Is VO2max Measured?

VO2max is measured in ml/kg/min, 

Example: milliliters of oxygen per kilogram of body weight per minute, with essentially two determining factors:

• How much blood the heart pumps to the muscles each beat (cardiac output)
• How efficiently the muscles extract oxygen from the blood and utilize it

VO2 max can be measured through various methods of physical evaluations. These can be direct as in a lab or indirect, using submaximal tests outside of the lab setting.                          Lab tests are not easy to come by and can be expensive. 

Sub-max tests are used in Physical Education classes. Example: Beep-Test

The information in the tables are read by: Level / Shuttle Number

VO2max is only one half of the equation

The other includes: 

• skill training
• proper technique
• mental preparation
• psychological profile
• diet
• genetics
• age
• gender
• lactate threshold training
• location

HOW TO TRAIN YOUR VO2 MAX

According to research, high-Intensity Interval Training, or HIIT for short, is the ideal way of improving your V02 max, as it challenges your cardiovascular system to work to maximum effort.

HIIT workouts consist of performing intervals of intense aerobic exercise, like running, spinning, or swimming, taking a recovery break, then repeating the whole cycle for a specific amount of time.

Sample HIIT session for improving for your V02 max

• Warm-up for 10 to 15 minutes by jogging at a steady pace, then perform 8 to 10 dynamic exercises to get your body ready for intense exercise.
• Once you're warmed up, run as fast as you can for one minute.
• Take a one-minute break. Slow down and jog slowly.
• Repeat the on and off cycle for 15 to 20 minutes.
• End your session with a 5-minute cooldown jog.

The more you push yourself (the higher the RPE Scale), the better (within reason).

How can you increase the capacity of your lactic system?

You can enhance the capacity of the lactate producing system by performing repeated bouts of sustained 20 to 60 second supra-maximal exercise - exercise performed above 100 percent of your maximum fitness capacity. 

This maximally stimulates the glycolytic system and, in doing so, challenges the enzymes that limit glycolytic energy production.

Lactate

When we do strenuous exercise, we breathe faster in order to transfer more oxygen to the working muscles.

In most cases our bodies naturally prefer to generate energy using the aerobic system (meaning, "with oxygen"). 

When our bodies are under stress - trying to lift heavy weights or perform fast sprints - we switch to the anaerobic system ("without oxygen") to produce this energy.

When this happens, the body produces a substance called lactate which allows the breakdown of glucose - and the production of energy - to continue. 

Pyruvate, a byproduct of glucose breakdown, is converted to lactate, which accumulates in your muscles, especially during high-intensity exercise.

The higher the glucose flux into the cell, the higher the lactate production. 

MYTH #1

The first and most common misunderstanding of lactate is that it is only produced during intense exercise. This could not be further from the truth. It is being created within your body at all times, even while you are seated reading this post. As lactate is produced, it circulates in the blood as a valuable energy source and is preferred by various tissues. You don't notice lactate is being produced due to your body's ability to effectively move it around and use it before accumulation occurs.

By: Matt Van Dyke  

MYTH #2

The second common misunderstanding is that lactate is a cause of delayed muscle soreness. At high-intensity training, rapid lactate production has the ability to cause a burning feeling by activating free nerve endings. However, lactate is cleared from the muscle cell within two to four minutes post-training. This rate of clearance from the cell can also be improved with proper training. Lactate accumulation is cleared far too rapidly for it to be a cause of delayed muscle soreness.

By: Matt Van Dyke   

MYTH #3

The third misunderstanding is that increases in lactate accumulation causes the muscle cell to become more acidic, is quite possibly the most widely misunderstood aspect of lactate. The actual functional role of lactate is to work as an intracellular buffer and to prevent acidosis within the muscle cell. 

By preventing a large change in pH inside the cell, lactate has the ability to allow work to continue for a longer period of time before the effects of acidosis on muscle function, and thereby, performance is evident. 

During high intensity exercise, Type II-Fast Twitch muscle fibres are fully recruited, due to high contractile demands by skeletal muscle to produce energy (ATP). 

Type II muscle fibres are highly glycolytic (they use lots of glucose) which results in the production of high amounts of lactate. This production is a natural by-product of glucose utilization by skeletal muscle cells.

Lactate Threshold (LT)

Lactate threshold is defined as the intensity of exercise at which lactate begins to accumulate in the blood at a faster rate than it can be removed.

Unbuffered acid is added to the blood, a condition that makes you feel weak and like you have to vomit, lose control of bladder or bowels and you must stop right away.   

When we crank up the intensity, we need more ATP than ETC can produce at its maximal output. The only way to make up the difference is to rev up Glycolysis. In doing so, our cells make lots of lactate that spills into the blood

When the concentration of lactate in the blood starts to climb, our brain senses this and we start to feel nauseous. 

Within a few minutes we are forced to drop the intensity, ATP demand reduces, Glycolysis is slowed, lactate is cleared from the blood, and all is back to normal.

The advantage of having a high LT is that you can work at a higher intensity for a longer time before lactate levels become intolerable.

By Dr. Alexander Hutchison: https://www.active.com/triathlon/articles/lactate-threshold-and-v02-max-explained?page=2 

Higher blood lactate levels actually slow down the muscle's capacity for more work. 

If it seems counter-intuitive that the body would produce something that actually reduces its ability to perform, it's not. 

It turns out that lactic acid is a natural defense mechanism that prevents us from over-doing it and doing ourselves permanent damage.

ANDREW KILDING: The accumulation of lactic acid in the muscles has long been incorrectly associated with fatigue during exercise, as well being linked with delayed-onset muscle soreness (DOMS). 

Even today you'll hear sports commentators saying, "athlete X must be fatiguing/tiring because of lactic acid build up". We know now that this is not the case, as lactic acid has no direct role in causing these exercise-related symptoms.

The term "lactic acid" is often incorrectly interchanged with "lactate." Although they are used in the same context, they are two different substances due to a one proton difference between the two 

What are the benefits of lactic acid?

The production of lactate serves to reduce acidity in the blood and muscle in an attempt to maintain an optimal pH level in the muscle, and to allow the muscle to keep contracting at high rates. However, this "buffering" can't last forever, so when pH in the muscle starts to drop and hydrogen ions accumulate, this is when the sensation of "burning" is felt as the disruption to the muscle's ability to contract starts to occur.

Lactate also helps to preserve other fuel stores and is a direct source of energy for the muscles, heart and brain. The body is efficient at re-using lactate and can even "shuttle" lactate to different parts of the muscle and between tissues.

Most Lactic Acid can be cleared in about 1 hour and it is quicker if you do ACTIVE RECOVERY (aka movement)

LACTATE IS A BUFFER

Lactate has the ability to accept hydrogen ions, which contribute to a pH change in muscle, making it an important buffer. 

With muscular pH being an important limiting factor in repeat-sprint abilities, it is vital to train the body to buffer as effectively as possible. 

This means athletes involved in repeat-effort sprint bouts, such as many team sports, as well as athletes with multiple competitions within a short time period have the greatest potential to improve through lactate training.

The Cori cycle (also known as the Lactic acid cycle)

is the metabolic pathway where lactate produced by anaerobic glycolysis in the muscles moves to the liver and is converted to glucose, which then returns to the muscles and is used to make ATP.