VO2max in fitness

It is the maximum oxygen consumption that a subject has during rhythmic, protracted and intense muscular activity, which engages large muscle masses (generally the lower limbs), breathing air, at sea level.
In practice it is the maximum quantity of O2 that can be captured - transported - used by the organism and represents the ability of an individual to produce and use energy, generated by the aerobic oxidative system.
These two not strictly scientific definitions help us understand the importance of VO2max as a parameter for evaluating an individual's cardiovascular fitness status.
The American Heart Association drew up a table in 1972 which classified the various levels of fitness as a function of age, sex and relative VO2max.

So let's start distinguishing between absolute and relative VO2max:

The first expresses the capacity to use oxygen in liters / minute, while the second also considers body weight in this ratio and the expression is transformed into ml / kg / min. The relative value is more suitable for evaluating individuals who do not have specific competitive or very high level needs (that is, all of us IC practitioners !!)
How to calculate the maximum oxygen consumption in your gym?

Let's start by saying that maximum and direct tests are the exclusive competence of medical personnel carried out in suitably equipped centers. We can only carry out submaximal and indirect tests, which use the heart rate as a reference parameter (there is a mathematical correlation between% HRM and% VO2max) and which in any case do not exceed 80% of HRM. it is the maximum that the current legislation allows in the presence of a medical certificate issued by the general practitioner. Everyone draw their own conclusions.
Personally I consider the Y.M.C.A bike protocol valid (Golding, Mavers, Sinning, 1989). This test uses only three or four phases with increasing intensity on a cycle ergometer and if during the execution the subject exceeds 85% of HRM the test is interrupted and only the data available are used. The first phase is the same for everyone, you start pedaling with a load of 25 watts, while the remaining loads vary according to the heart response.
C "it should be noted that in trained subjects the values will be overestimated, on the contrary in sedentary ones they will be underestimated.

It is useful to know that the MET or metabolic equivalent is directly correlated with the relative VO2max, which is defined as a multiple of the basal metabolic rate. The relationship can be expressed as follows:

1 MET = 3.5 mlO2 / Kg / min

This very important relationship, provided we know the basal metabolic rate of the subject in question, gives us the exact measure of the energy expenditure necessary to perform a certain work protracted for a certain time.
This notional list may leave us indifferent and perhaps a little confused. An example could perhaps awaken the attention and make the rapidly expressed concepts clearer.

Subject: Francesco Calise

age: 41 years

weight: 68kg

height: 174 cm
Fat mass: 6%

Fat mass: 4Kg (Jackson et al. Protocol)
MBR Reconstruction: 1996.8 Kcal / d (Keys and Grande protocol)
Absolute VO2max: 4.30 l / min

Relative VO2max: 63.2 ml / min / Kg
MET: 18.06 (= VO2max rel / 3.5)

Data in hand we assume that the indicated subject performs for 45 min. an "activity that engages him at an average of 70% of the maximum heart rate (HRM) (a type class of i.c.) here is what we can get:
We know that 70% of MHR corresponds to 56% of VO2max, so the average metabolic effort for the duration of the exercise will have been 56% of 18.06 or 10.41 Met.

Basically for 45 minutes I will have sustained an energy consumption about 10 times higher than my MBR (basal metabolism), so here is the simple calculation to do:

[(1996.8 / 24/60) x45] x10.41 = about 650 Kcal

of which 56% by sugar and the remaining 44% by fat (direct correlation with the average percentage of VO2max). Wanting to complicate life and going further with the calculations, we obtain the grams of fat used during exercise (without considering the work of our body to restore the hepatic and muscle glycogen stores)

(650x44%) / 9 (the Kcal contained in 1g of fat) = 31.8 g

At this point I would like to make two reflections.

The first is that the more you train (constancy pays much more than the one-off stoic suffering) the more you consume with the same intensity of work, the second is that with little knowledge you get data that are much more reliable in terms of fitness ( because they are really customized) than those indicated by very expensive heart rate monitors.

ESSENTIAL CLARIFICATION:

What is written is valid exclusively for healthy subjects and in the absence of pathologies in progress and assuming a non-protein respiratory quotient ....

... about this "last topic, have you ever heard phrases in the gym (often for the use of gentlemen) like:" Finally, after so many sacrifices I have lost X Kg but now I am obviously a little more flaccid, from tomorrow I will start to do something to firm up! ".
At this point the "devastation" has occurred !!

Training error plus power supply error, continue ...