Deno N S, Kamon E, Kiser D M
Am Ind Hyg Assoc J. 1981 Aug;42(8):616-23. doi: 10.1080/15298668191420378.
Respirators which impose a resistance to breathing may cause a limitation in maximum exercise intensity. This limitation is of particular concern when respirators are used in emergency situations requiring high levels of exercise intensity. Many studies have defined the limitations of exercise intensity imposed by breathing resistance as the point where the subject feels "uncomfortable". Perhaps of greater importance is the true physiological limit. Using motivated subjects, the physiological limits of exercise intensity and related respiratory responses resistances of 11, 16, 25, 40, and 57 cm H2O pressure at a flow rate of 120 L.min-1 exercise limits were 72, 72, 79, 60, and 54 percent of maximum aerobic capacity (% VO2 max) for the short term and 58, 60, 49, 43, and 35% VO2max for the prolonged exercise (1 hour). The presence of significant external resistance to breathing was found to influence the traditional relationship between exercise intensity and duration.
对呼吸产生阻力的呼吸器可能会限制最大运动强度。当在需要高强度运动的紧急情况下使用呼吸器时，这种限制尤其令人担忧。许多研究将呼吸阻力所导致的运动强度限制定义为受试者感到“不适”的点。或许更重要的是真正的生理极限。以有积极性的受试者为对象，在流速为120L·min⁻¹时，11、16、25、40和57cmH₂O压力的呼吸阻力下，短期运动极限分别为最大有氧能力（%VO₂max）的72%、72%、79%、60%和54%，长时间运动（1小时）时分别为58%、60%、49%、43%和35%VO₂max。研究发现，显著的外部呼吸阻力会影响运动强度与持续时间之间的传统关系。
