Model for Integral Assessment of Students’ Physical Health. Teaching and Methodological Manual - страница 5
Figure 1. Pulmonary volumes and capacities.
According to the commonly accepted classification, primary lung volumes are combined into so-called lung capacities, of which there are also four. The most commonly used in practice to assess a person’s physical development is the vital capacity of the lungs (VCL) – the amount of air that can be exhaled from the lungs after a maximum inhalation. VCL consists of three volumes: VCL = tidal volume (TV) + inspiratory reserve volume (IRV) + expiratory reserve volume (ERV).
1.1. Assessment of physiometric indicators
Vital Capacity (VC)
The normal value of VC depends on the person’s gender and age, body type, physical development, and may significantly decrease in various illnesses, reducing the body’s ability to adapt to physical stress.
In men, the normal VC is calculated at 60 milliliters per 1 kilogram of weight for non-athletes and 65 milliliters or more for athletes, while in women, it is 50 and 55 milliliters, respectively. The average VC is about 2.5—4 liters for women and 3.5—5 liters for men. Absolute VC values are not very informative due to individual variability. It is recommended to calculate «due» values when assessing the condition.
Calculation of the predicted lung capacity (PLC) in liters:
PLC for men = 5.2 x H – 0.029 x A – 3.2
PLC for women = 4.9 x H – 0.019 x A – 3.76
H – height in meters, A – age in years.
The actual lung capacity is considered reduced if it is less than 80% of the PLC. Lung capacity indirectly reflects the size of the respiratory surface of the lungs, where gas exchange occurs between alveolar air and blood in pulmonary capillaries. In other words, the larger the lung capacity, the greater the respiratory surface of the lungs. In addition, the larger the lung capacity, the deeper the breath and the easier it is to achieve an increase in ventilation volume. Thus, lung capacity determines the ability of the body to adapt to physical exertion, to a lack of oxygen in the inhaled air (for example, when ascending to altitude). Lung capacity is an indicator that largely determines the functional capabilities of the external respiratory system. A decrease in lung capacity always indicates some pathology. Lung capacity cannot and should not be considered the only indicator of increased function of the external respiratory system. It only determines the functional capabilities of this system in terms of providing the body with the necessary amount of oxygen. Therefore, the potential capabilities of the external respiratory system in a person with high lung capacity are higher (larger respiratory surface and the ability to deepen breathing) than in a person with low lung capacity.