This is the second part (the first was about VO2max) of a journey into the evaluation of the runner's performance, made possible with the big support of Mark Henninger (himaxx Centre for Altitude Training - Berlin, Germany), that provided the ergospirometer, the treadmill, the hypoxic chamber and his knowledge for the tests. Thanks Mark!
During exercise the whole-body energy requirement increases 20 to 30 times above resting levels, but what are the relative contribution of Carbohydrates, Lipids and Proteins in the different energy transfer systems?
First of all, we need to define the above-mentioned "resting levels": the BMR (Basal Metabolic Rate) is the amount of energy expended daily by humans and other animals to sustain vital functions in the waking state. Under controlled laboratory conditions, after at least 3 hours from the last light meal and without prior physical activity, the RMR (Resting Metabolic Rate) can be measured. The TDEE (Total Daily Energy Expenditure) can be divided as follows:
RMR accounts for 60 to 75% of TDEE;
thermic effects of eating account for around 10%;
physical activity accounts for the remaining 15 to 30%.
The first part of the ergospirometry is exactly the measurement of the RMR: without taking into account the Proteins' contribution (being far enough from the last meal and without doing any prior physical activity allow this approximation), the machine can split the energy expenditure between Carbohydrates and Lipids measuring ventilation and oxygen and carbon dioxide concentration of the inhaled and exhaled air. There are some generalized equations to predict the Resting Daily Energy Expenditure (if anyone is interested, please contact me and I will write something more specific), but the direct measurement is always the most accurate solution.
As an example, in the Table presented below a set of typical data resulting from the RMR analysis with the ergospirometer is shown.
Table 1 - RMR analysis data.
The third part will be about the energy expenditure during exercise. Meanwhile...keep on training, people!
Here you can find a list of my running-related posts. Now shut down the notebook and have a run!