Roger L J, Kehrl H R, Hazucha M, Horstman D H
J Appl Physiol (1985). 1985 Sep;59(3):784-91. doi: 10.1152/jappl.1985.59.3.784.
Young male volunteers with mild asthma and hypersensitivity to methacholine were exposed for 75 min with natural breathing to 0.0, 0.25, 0.5, and 1.0 ppm SO2. Each exposure included three 10-min periods of moderate treadmill exercise (minute ventilation 21 l . m-2 . min-1, O2 consumption 25 ml . kg-1, and heart rate 120/min). Specific airway resistance (sRaw) was not significantly increased after exercise in 0.25 ppm SO2, relative to the control exposure (clean air). In 0.5 and 1.0 ppm SO2, sRaw was increased twofold and threefold above preexposure levels, respectively, corresponding to increases of 3.2 and 9.2 cmH2O . s in excess over the increases seen in clean air (P less than 0.001). There was a broad range of responses to exercise and SO2. The increases in sRaw after the second and third exercises were significantly less than after the first exercise. Respiratory impedance measured by forced random noise suggests that the induced bronchoconstriction was primarily associated with peripheral airways. These results confirm that mild asthmatics selected for methacholine sensitivity have as a group significant bronchoconstriction in response to short-term moderate exercise with natural breathing in 1.0 and 0.5 ppm SO2. In addition, the induced bronchoconstriction is decreased after short-term repeated exercise in SO2.
患有轻度哮喘且对乙酰甲胆碱过敏的年轻男性志愿者，在自然呼吸状态下暴露于0.0、0.25、0.5和1.0 ppm的二氧化硫中75分钟。每次暴露包括三个10分钟的中等强度跑步机运动时段（分钟通气量21 l·m⁻²·min⁻¹、耗氧量25 ml·kg⁻¹、心率120次/分钟）。与对照暴露（清洁空气）相比，在0.25 ppm二氧化硫中运动后，比气道阻力（sRaw）没有显著增加。在0.5和1.0 ppm二氧化硫中，sRaw分别比暴露前水平增加了两倍和三倍，比在清洁空气中观察到的增加量分别高出3.2和9.2 cmH₂O·s（P小于0.001）。对运动和二氧化硫的反应范围很广。第二次和第三次运动后sRaw的增加显著小于第一次运动后。通过强迫随机噪声测量的呼吸阻抗表明，诱发的支气管收缩主要与外周气道有关。这些结果证实，因对乙酰甲胆碱敏感而被挑选出的轻度哮喘患者，作为一个群体，在自然呼吸状态下，对1.0和0.5 ppm二氧化硫中的短期中等强度运动有显著的支气管收缩反应。此外，在二氧化硫中短期重复运动后，诱发的支气管收缩会减弱。
