Morrison J B, Butt W S, Florio J T, Mayo I C
Undersea Biomed Res. 1976 Sep;3(3):217-34.
The ventilatory response of four subjects was measured at rest and various intensities of exercise. Experiments were conducted in a dry pressure chamber (1) at 1 ATA and 4 ATA with the subjects breathing from a low-resistance mouthpiece, and (2) at ATA with the subjects breathing from open-circuit breathing apparatus (Royal Naval Swimmers' Air Breathing Apparatus). At 4 ATA there was significant hypoventilation and hypercapnia, together with an increased tidal volume and lower respiratory frequency. The use of the breathing apparatus tended to amplify these changes in ventilatory response. In addition, the extent of hypercapnia at 4 ATA was related to the exercise intensity. When subjects breathed from a low-resistance mouthpiece, oxygen uptake was significantly greater at 4 ATA than at the surface for the same ergometric work load, but when they breathed from the breathing apparatus, the increase in oxygen uptake was not significant in comparison to surface values. At 4 ATA bradycardia was evident at all levels of exercise but was not affected significantly by the presence of the breathing apparatus.
测量了四名受试者在静息状态和不同运动强度下的通气反应。实验在干燥压力舱中进行：（1）在1个绝对大气压（ATA）和4个ATA时，受试者通过低阻力口罩呼吸；（2）在1个ATA时，受试者通过开路呼吸装置（皇家海军游泳者空气呼吸装置）呼吸。在4个ATA时，出现明显的通气不足和高碳酸血症，同时潮气量增加，呼吸频率降低。使用呼吸装置往往会放大通气反应的这些变化。此外，4个ATA时高碳酸血症的程度与运动强度有关。当受试者通过低阻力口罩呼吸时，在相同的测力计工作负荷下，4个ATA时的摄氧量明显高于海平面时，但当他们通过呼吸装置呼吸时，与海平面值相比，摄氧量的增加并不显著。在4个ATA时，在所有运动水平下均出现明显的心动过缓，但呼吸装置的存在对其没有显著影响。
