Kurihara N, Matsushita H, Wakayama K, Fujimoto S, Nakano N, Hirata K, Ohta K, Takeda T
First Department of Internal Medicine, Osaka City University Medicine School, Japan.
Nihon Kyobu Shikkan Gakkai Zasshi. 1992 Apr;30(4):554-60.
We studied the possibility that during incremental exercise anaerobic threshold (AT) is associated with an increase in breathlessness in subjects with increased impedance or respiratory system. Six patients with chronic lung diseases (CLD) and six healthy subjects performed cycle ergometer exercise under two conditions; with free resistive loading and with 9 cmH2O/l/sec of inspiratory resistive loading (IRL). Ventilation, respiratory pattern, VO2, VCO2, were measured every 15 sec by a metabolic cart, Minato Respiromonitor RM 300. AT was determined by V-slope method. Mouth occlusion pressure (P0.1) was also measured in six subjects during exercise. The subjects selected a number of modified Borg scale (psi) to express their breathlessness during exercise by pushing a electrically potentiated remote button. Slopes of changes in psi with increasing work-load, delta psi/delta watt-slope, were calculated before and after V-slope AT, and each inflection point of VE, respiratory rate, VT/Ti, and VCO2. In order to evaluate which parameters are the most responsible for a change in psi, statistical significance (P-value) in changes of slope of each parameters were compared. The delta psi-slope increased with the highest significance after AT point. Under IRL the significance was more pronounced. There was a highly significant linear correlation between P0.1 and psi during exercise both under free resistive loading and IRL. In addition the increase of P0.1 with incremental exercise was characterized by a presence of inflection at a workload of V-slope AT in most of the subjects. From these results it was concluded that anaerobic threshold was closely associated with an increase of breathlessness during exercise via enhancing respiratory motor command.(ABSTRACT TRUNCATED AT 250 WORDS)
我们研究了在递增运动过程中，无氧阈（AT）是否与呼吸系统阻抗增加的受试者呼吸急促加剧相关的可能性。六名慢性肺病（CLD）患者和六名健康受试者在两种条件下进行了蹬车测力计运动，即自由阻力负荷和9 cmH₂O/l/秒的吸气阻力负荷（IRL）。通过Minato Respiromonitor RM 300代谢仪每15秒测量一次通气、呼吸模式、VO₂、VCO₂。采用V斜率法测定无氧阈。在运动过程中，还对六名受试者测量了口腔闭合压（P0.1）。受试者通过按下电动遥控按钮，选择改良的博格量表（psi）数字来表达运动时的呼吸急促程度。计算V斜率无氧阈前后，psi随工作负荷增加的变化斜率，即delta psi/delta瓦特斜率，以及每一个VE、呼吸频率、VT/Ti和VCO₂的拐点。为了评估哪些参数对psi变化的影响最大，比较了各参数斜率变化的统计学显著性（P值）。无氧阈点之后，delta psi斜率增加的显著性最高。在IRL条件下，这种显著性更为明显。在自由阻力负荷和IRL两种情况下，运动过程中P0.1与psi之间均存在高度显著的线性相关性。此外，在大多数受试者中，随着递增运动P0.1的增加在V斜率无氧阈的工作负荷处存在一个拐点。从这些结果得出结论，无氧阈通过增强呼吸运动指令与运动过程中呼吸急促的增加密切相关。（摘要截选至250词）
