Jackson Anna R, Hull J H, Hopker James G, Fletcher Hannah, Gowers William, Birring Surinder S, Dickinson John W
School of Sport and Exercise Sciences, University of Kent, Chatham, UK.
English Institute of Sport, London, UK.
ERJ Open Res. 2020 Jun 22;6(2). doi: 10.1183/23120541.00271-2019. eCollection 2020 Apr.
Respiratory symptoms, including cough, are prevalent in individuals with asthma when exercising. This study investigates whether a heat and moisture exchanger (HME) face mask is effective in modulating exercise-induced bronchoconstriction (EIB) and post-exercise cough in a cold, dry environment in individuals with asthma. Twenty-six participants diagnosed with asthma (20 males, 6 females) completed three cycling exercise challenges at 8°C and 24% relative humidity in a randomised order. Participants wore either an HME mask (MASK), sham mask (SHAM), or no mask (CONT). Following a 3-min warm-up, participants completed 6-min cycling at 80% peak power output. Before and after exercise, maximal flow-volume loops were recorded. Post-exercise cough was monitored with a Leicester Cough Monitor (LCM) for 24 h. Results were analysed using repeated-measures ANOVA and Friedman's tests and data were presented as the mean±sd or median (interquartile range (IQR)). Eleven participants failed to demonstrate EIB ( >10% fall in forced expiratory volume in 1 s after exercise) and were removed from analysis. The percentage fall in forced expiratory volume in 1 s following exercise in CONT was greater than MASK (MASK: -6% (7%), SHAM: -11% (11%), CONT: -13% (9%); p<0.01). No difference was found between exercise in cough count per hour over the 24-h monitoring period or the number of coughs in the first hour after exercise. HME masks can attenuate EIB when exercising in cold, dry environments. The SHAM mask may not have been entirely inert, demonstrating the challenges of running randomised control trials utilising control and sham conditions.
包括咳嗽在内的呼吸道症状在哮喘患者运动时很常见。本研究调查了在寒冷、干燥环境中，湿热交换器（HME）面罩对哮喘患者运动诱发的支气管收缩（EIB）和运动后咳嗽是否有调节作用。26名被诊断为哮喘的参与者（20名男性，6名女性）在8°C和相对湿度24%的环境下，以随机顺序完成了三次自行车运动挑战。参与者分别佩戴HME面罩（MASK）、假面罩（SHAM）或不戴面罩（CONT）。在进行3分钟的热身运动后，参与者以80%的峰值功率输出完成6分钟的骑行。运动前后，记录最大流量-容积环。使用莱斯特咳嗽监测仪（LCM）对运动后的咳嗽进行24小时监测。结果采用重复测量方差分析和弗里德曼检验进行分析，数据以平均值±标准差或中位数（四分位间距（IQR））表示。11名参与者未能表现出EIB（运动后1秒用力呼气量下降>10%），被排除在分析之外。CONT组运动后1秒用力呼气量下降的百分比大于MASK组（MASK组：-6%（7%），SHAM组：-11%（11%），CONT组：-13%（9%）；p<0.01）。在24小时监测期内，每小时咳嗽计数或运动后第一小时咳嗽次数方面，各运动组之间未发现差异。HME面罩在寒冷、干燥环境中运动时可减轻EIB。假面罩可能并非完全无活性，这表明在使用对照组和假条件进行随机对照试验时存在挑战。
