Modern life carries bad habits that can put at risk people's health, but human beings are made to move. It is true that technology (smartphones, tablets, etc.) continues to advance and offer unique communication opportunities. However, it is also true that it represents a huge risk world’s population at large, encouraging a greater degree of sedentariness than in the past.
To that extent, Technogym has launched Let's Move for a Better World, the largest social campaign in the fitness and wellness sector with the aim to share with operators both a business opportunity to attract more members, and a social opportunity to promote health and wellness in their local communities.
With that said, what happens instead to our body when we do physical activity? In this article, we will talk about how our body burns oxygen (among other things) and the value of the metabolimeter, a medical device with which you can analyse the energy burned by your body.
VO2 measurement
Every time we do a physical activity, our body "burns" energy deriving mainly from the food we eat and from our body's reserves: adipose tissue and muscle glycogen. The conversion of these reserves into energy, however, is not an easy process and our body has developed, during its evolution, different systems to do so.
There are methods to indirectly calculate VO2 max, but the metabolimeter allows to obtain data on the individual sportsman with a higher level of accuracy.
Some of these processes, such as cellular glycolysis, do not require the presence of oxygen in order to take place and are therefore part of the so-called anaerobic metabolism. Others, such as mitochondrial oxidative phosphorylation, require oxygen as an essential element and therefore fall within the processes that are part of aerobic metabolism.
1. VO2 – consumption of oxygen
In physiology, in order to assess the extent of the processes underlying aerobic metabolism, it is usual to measure the volume of oxygen consumed in a given time. This volume is usually indicated by the acronym VO2. By doing physical activity, particularly during prolonged activities such as running or cycling, our body meets increased energy demands through the consumption of high-energy molecules such as sugars, starches and lipids, but to ensure that these molecules produce energy, there must be oxygen available within the muscle fibres and mitochondria that is "consumed" during the process of energy production.
Consequently, the higher the VO2 consumed during the activity, the greater the energy produced. VO2 is therefore the main parameter to define the aerobic capacity of an individual, i.e. the ability to produce energy through mechanisms that require the use of oxygen. The latter parameter is of importance for training and health assessment of the cardiorespiratory system. The maximum aerobic capacity of an individual, in fact, is crucial for the athletic performance of the most VO2 demanding sports. Coaches and personal trainers, therefore, tend to plan the intensity of training sessions offered to their athletes and customers based on this parameter.
2. Measuring oxygen consumption
Aerobic capacity cannot be measured directly without special instruments. Therefore, many companies have developed devices, commonly called metabolimeters, capable of measuring VO2 (and VO2 max) through the gaseous exchanges that occur during breathing. However, it should be emphasized that the measurement of VO2 max is highly dependent on the type of exercise performed.
This parameter, for example, generally varies if measured during the race or pedalling. In addition, the way in which a given exercise is performed is also important. Let's take the run, for example.
Depending on the type of training, duration and nature of our body, sugars or fats are burned, but in any case this "combustion" is accompanied by the consumption of oxygen.
Typically, VO2 max measurement includes standard exercise protocols called "ramp", when the treadmill speed is progressively increased, or "step", when the speed increases at regular intervals. Depending on the type of training, duration and nature of our body, sugars or fats are burned, but in any case, this "combustion" is accompanied by the consumption of oxygen. The objective is always to reach the maximum speed sustainable by the subject for a certain period. However, the way in which the speed grows can lead to different results and thus to different maximum VO2.
Since there are many variables to consider when choosing the optimal test protocol, it is therefore important to consult specialised personnel when attempting this type of test. Since direct tests for measuring VO2 max are extremely tiring and require special instrumentation as well as specialised personnel, "indirect" and/or "sub-maximal" test methods have also been developed. These have the advantage of not requiring maximum efforts or special equipment. However, this is at the expense of the accuracy and reliability of the results obtained.
3. Oxygen consumption and energy expenditure
As we have seen, VO2 is a measure of the body's ability to produce energy using oxygen. However, this is not only true during exercise, but also at rest. This is called the basal metabolism, i.e. the amount of energy the body needs to support itself in a state of absolute rest.
Under these conditions, the necessary energy is basically produced by aerobic processes, so VO2 is the ideal parameter to calculate energy expenditure at rest. On average, in fact, an individual at rest consumes 1 MET, or 1 kcal per kilogram of weight per hour. At the same time, however, 1 MET is also equivalent to 3.5 ml of oxygen consumed per kilo of weight per minute. This relationship between MET and VO2 is of fundamental importance because it makes possible to estimate, based on VO2, the individual energy expenditure of a given physical activity, even in a state of rest. Therefore, thanks to the metabolimeter, it is not only possible to evaluate the aerobic capacity of an individual, but also to estimate the basal metabolic rate and the energy expenditure during the activity.
4. Why metabolimeters are important
The analysis of VO2 using metabolimeters is of great importance for athletes. Indeed, it allows you to accurately assess both aerobic capacity and energy expenditure both during physical activity and at rest. With this information available, coaches, sports physicians and nutritionists can then design highly personalized workouts, assess physical fitness and evaluate appropriate dietary programs based on the needs of individuals.
With mywellness, you can track every activity in the gym or outdoors, measuring the miles covered and the calories burned. Each physical activity will allow you to accumulate MOVEs, a unit of measure that you can compare with friends to find out who is more active. Thanks to the exclusive Technogym Ecosystem, made up of the most innovative equipment connected to Technogym, the digital platform mywellness offers content and training programs and allows operators to offer different training experiences to different people with different needs and passions.
- American College of Sports Medicine. ACSM’s Guidelines for Exercise Testing and Prescription. 9th edition. Philadelphia, PA: US: Lippincott Williams & Wilkins; 2014.
- Bentley DJ, Newell J, Bishop D. Incremental Exercise Test Design and Analysis. Sport Med. 2007;37(7):575–86.
