Centre for Heart Lung Innovation, Vancouver, BC, Canada; Department of Physical Therapy, The University of British Columbia, Vancouver, BC, Canada.
Centre for Heart Lung Innovation, Vancouver, BC, Canada; Department of Medicine, The University of British Columbia, Vancouver, BC, Canada.
Chest. 2022 Mar;161(3):662-675. doi: 10.1016/j.chest.2021.10.020. Epub 2021 Oct 23.
Individuals with COPD have increased sensitivity to traffic-related air pollution (TRAP) such as diesel exhaust (DE), but little is known about the acute effects of TRAP on exercise responses in COPD.
Does exposure before exercise to TRAP (DE titrated to 300 μg/m particulate matter < 2.5 μm in diameter [DE]) show greater adverse effects on exercise endurance, exertional dyspnea, and cardiorespiratory responses to exercise in participants with mild to moderate COPD compared with former smokers with normal spirometry and healthy control participants?
In this double-blind, randomized, placebo-controlled, crossover study, 11 healthy control participants, nine former smokers without COPD, and nine former smokers with COPD were separately exposed to filtered air (FA) and DE for 2 h separated by a minimum of 4 weeks. Participants performed symptom-limited constant load cycling tests within 2.5 h of exposure with detailed cardiorespiratory and exertional symptom measurements.
A significant negative effect of TRAP on exercise endurance time was found in healthy control participants (DE vs FA, 10.2 ± 8.2 min vs 12.9 ± 9.5 min, respectively; P = .03), but not in former smokers without COPD (10.1 ± 6.9 min vs 12.2 ± 8.0 min, respectively; P = .57) or former smokers with COPD (9.8 ± 6.4 min vs 8.4 ± 6.6 min, respectively; P = .31). Furthermore, significant increases in inspiratory duty cycle and absolute end-expiratory and end-inspiratory lung volumes were observed, and dyspnea ratings were elevated at select submaximal measurement times only in healthy control participants.
Contrary to our hypothesis, it was the healthy control participants, rather than the former smokers with and without COPD, who were negatively impacted by TRAP during exercise.
ClinicalTrials.gov; No.: NCT02236039; URL: www.
gov.
患有 COPD 的个体对交通相关的空气污染（TRAP）如柴油废气（DE）更为敏感，但对于 TRAP 对 COPD 患者运动反应的急性影响知之甚少。
与正常肺量计的前吸烟者和健康对照参与者相比，运动前暴露于 TRAP（将 300μg/m 粒径小于 2.5μm 的颗粒物[DE]滴定）是否会在前吸烟者中轻度至中度 COPD 患者的运动耐力、运动性呼吸困难以及运动时心肺反应产生更大的不良影响？
在这项双盲、随机、安慰剂对照、交叉研究中，11 名健康对照参与者、9 名无 COPD 的前吸烟者和 9 名有 COPD 的前吸烟者分别暴露于过滤空气（FA）和 DE 2 小时，两者之间至少间隔 4 周。参与者在暴露后 2.5 小时内进行症状限制的恒负荷踏车测试，并进行详细的心肺和运动症状测量。
在健康对照参与者中发现 TRAP 对运动耐力时间有显著的负面影响（DE 与 FA 相比，分别为 10.2 ± 8.2 分钟和 12.9 ± 9.5 分钟；P =.03），但在前吸烟者中无 COPD（10.1 ± 6.9 分钟与 12.2 ± 8.0 分钟相比，分别；P =.57）或前吸烟者中 COPD（9.8 ± 6.4 分钟与 8.4 ± 6.6 分钟相比，分别；P =.31）中没有发现这种影响。此外，仅在健康对照参与者中观察到吸气功比、绝对呼气末和吸气末肺容积的显著增加，并且在选择的次最大测量时间呼吸困难评分升高。
与我们的假设相反，在运动过程中受到 TRAP 负面影响的是健康对照参与者，而不是有和没有 COPD 的前吸烟者。
ClinicalTrials.gov；编号：NCT02236039；网址：www.clinicaltrials.gov。
