Ventilatory efficiency can be evaluated using the relationship between minute ventilation (V'_E) and the rate of CO₂ production (V'_CO2). In accordance with the modified alveolar ventilation equation, this relationship is determined by changes in dead space volume (V_D) and/or the arterial CO₂ tension (P_aCO2) equilibrium point. In this review, we summarise the physiological factors that may account for normative ageing and pregnancy induced increases in V'_E/V'_CO2 during exercise. Evidence suggests that age-related increases in V_D and pregnancy-related decreases in the P_aCO2 equilibrium point are mechanistically linked to the increased V'_E/V'_CO2 during exercise. Importantly, the resultant increase in V'_E/V'_CO2 (ratio or slope), with normal ageing or pregnancy, remains below the critical threshold for prognostic indication in cardiopulmonary disease, is not associated with increased risk of adverse health outcomes, and does not affect the respiratory system's ability to fulfil its primary role of eliminating CO₂ and maintaining arterial oxygen saturation during exercise.

可以使用每分钟通气量 ( V ' _E ) 和 CO ₂生成速率 ( V ' _{CO 2} )之间的关系来评估通气效率。根据修改后的肺泡通气方程，这种关系由死腔容积 ( V _D ) 和/或动脉 CO ₂张力 ( P _{aCO 2} ) 平衡点的变化决定。在这篇综述中，我们总结了可能导致正常衰老和妊娠引起的V ' _E / V ' _{CO 2增加的生理因素}在运动过程中。有证据表明，与年龄相关的V _D增加和与怀孕相关的P _{aCO 2}平衡点降低与运动期间V ' _E / V ' _{CO 2}增加有机械联系。重要的是，由此导致的V ' _E / V ' _{CO 2增加}（比率或斜率），在正常衰老或怀孕的情况下，仍然低于心肺疾病预后指标的临界阈值，与不良健康结果风险增加无关，并且不影响呼吸系统履行其消除主要作用的能力CO ₂和运动期间维持动脉血氧饱和度。