The differences between gents and ladies impact the development of flow, new control regarding lung volume, pressure shifts therefore the following works from breathing.
But not, no differences is offered involving the sexes when WOB is versus some other percentages regarding maximal oxygen application (V?
Females’ smaller airways diameter and you can lung frequency trigger all the way down peak expiratory move and you may crucial potential. The initial effects is actually feminine has actually a smaller sized maximal flow–volume loop. Its capacity to generate increased venting throughout exercising is, hence, less with respect to dudes. This might predispose female to developing expiratory disperse restriction (EFL). EFL takes place when the move–frequency cycle away from a beneficial tidal breathing superimposes or is higher than new expiratory border of the limitation disperse–regularity contour. They includes expiratory move that can’t getting subsequent improved from the increasing the efforts of the expiratory looks, becoming maximumal at this tidal frequency . Meters c C laran mais aussi al. basic figured the smaller lung amounts and you can maximum circulate prices in women explanations enhanced incidence off EFL, with tidal frequency and you may minute venting being mechanically restricted at the higher workload. It is especially clear during the very complement feminine in finally phase away from do it [51, 52].
The regulation of lung volume during exercise is an important factor as it reflects the strategy by which tidal volume is achieved and it contributes to the work of breathing. Normally, the increased tidal volume during exercise is a consequence of an end-inspiratory lung volume increase and an end-expiratory lung volume (EELV) decrease with respect to the resting values. The reduction in EELV is similar between men and women throughout the majority of submaximal exercise and/or at a certain level of minute ventilation [52, 53]. By contrast, healthy fit women show a relative hyperinflation during heavy exercise and a higher rate of ventilation [50, 51]. This means that EELV increases at peak exercise. Specifically, dynamic hyperinflation occurs at the onset of significant EFL. It seems, therefore, that operational volume at maximal exercise depends on the presence or absence of EFL . In fact, when EFL is reduced by He–O2 (79% He–21% O2) breathing EELV is maintained lower than baseline . The presence of EFL during heavy exercise in healthy trained subjects, therefore, seems to trigger a reflex response that makes EELV increase to avoid dynamic compression of the airway downstream from the flow-limited segment . The operational lung volume, therefore, shifts towards higher volume.
Hyperinflation, ergo, can get trigger respiratory system exhaustion as it makes the inspiratory system price off a shorter length and in the current presence of reduced lung conformity [50, 52].
The combination of EFL and dynamic hyperinflation makes the work of breathing (WOB) and oxygen cost of hyperpnoea increase. Women, in fact, show a higher WOB than men across a range of ventilations during progressive exercise. It even becomes twice that of men when ventilation is above 90 L?min ?1 [51, 55]. O2max), although women have ?25% lower minute ventilation than their male counterparts. V?O2max is distributed among all the skeletal muscles, its relationship with the work performed being linear. D ominelli et al. demonstrated that this is also valid for the respiratory muscles that are morphologically and functionally skeletal muscles. They computed the oxygen uptake of the respiratory muscles (V?O2RM) over a wide range of minute ventilations, showing that the greater WOB in women is linearly associated with higher V?O2RM with less efficiency than men at submaximal and maximal exercise intensities. Women, in fact, are characterised by greater V?O2RM for a given WOB and ventilation, with V?O2RM representing a significantly greater fraction of whole-body oxygen consumption in women (?13.8%) than in men (?9.4%) . It can be speculated that a proportionally greater fraction of blood flow corresponds to the increased V?O2RM in women. This will possibly lead to an important competition for blood flow between respiratory and working muscles, particularly during heavy exercise [15, 50].
