Background

The acute effects of air pollution (AP) exposure during physical activity have been studied. However, comprehensive systematic reviews are lacking, particularly regarding moderate-to-vigorous physical activity (MVPA).

Objective

Our objective was to determine the acute health- and exercise-related effects of AP exposure during a bout of MVPA in healthy individuals.

Methods

We searched for randomized controlled trials in MEDLINE, Embase, Cochrane CENTRAL, SPORTDiscus, Agricultural and Environmental Science Database, ClinicalTrials.gov, International Standard Randomised Controlled Trial Number Registry, and the World Health Organization (WHO) International Clinical Trials Registry Platform up to July 2020 without language or date restrictions. Studies including healthy subjects engaging in a bout of MVPA while exposed to one or more of the following air pollutants were eligible: particulate matter, black carbon, carbon monoxide, nitrogen dioxide, ozone, diesel exhaust, and traffic-related air pollution (TRAP). Main outcome measures were markers of pulmonary function, symptoms, cardiovascular function, cognitive function, systemic inflammation, and exercise response. The evidence was synthesized by vote counting based on direction of effect.

Results

In total, 53 studies were included in the systematic review. Studies employed a heterogeneous mix of exercise protocols, AP interventions, and measured outcomes. Pooled results suggest ozone exposure during MVPA has an adverse effect on pulmonary function (100% [95% confidence interval (CI) 88–100], p < 0.001; high-certainty evidence) and reported symptoms (88% [95% CI 69–96], p < 0.001; low-certainty evidence). The effect of exposure to carbon monoxide, nitrogen dioxide, small engine exhaust, or diesel exhaust during MVPA on health- and exercise-related outcomes is uncertain because of insufficient evidence and the low to very low certainty of available evidence.

Discussion

The evidence is strongest for ozone, exposure to which generally induced a reduction in pulmonary function and increased symptoms during MVPA. The research related to other outcome domains remains inconclusive. Although long-term exposure to AP is proven to be hazardous, the evidence for healthy individuals to forgo MVPA during periods of high (non-ozone) pollution remains weak.

Trial Registration

Retrospectively registered in PROSPERO (CRD42020188280) on 10 July 2020.

中文翻译：

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运动对空气污染的急性影响：随机对照试验的系统评价

背景

已经研究了身体活动期间暴露于空气污染 (AP) 的急性影响。然而，缺乏全面的系统评价，特别是关于中度至剧烈运动（MVPA）的评价。

客观的

我们的目标是确定在健康个体的 MVPA 回合期间 AP 暴露对健康和运动相关的急性影响。

方法

我们检索了 MEDLINE、Embase、Cochrane CENTRAL、SPORTDiscus、农业和环境科学数据库、ClinicalTrials.gov、国际标准随机对照试验编号注册中心和世界卫生组织 (WHO) 国际临床试验注册平台中的随机对照试验，截至 7 月2020 年没有语言或日期限制。包括健康受试者在暴露于以下一种或多种空气污染物时参与 MVPA 的研究符合条件：颗粒物、黑碳、一氧化碳、二氧化氮、臭氧、柴油机尾气和交通相关空气污染 (TRAP) . 主要结局指标是肺功能、症状、心血管功能、认知功能、全身炎症和运动反应的标志物。

结果

总共有 53 项研究被纳入系统评价。研究采用了运动方案、AP 干预和测量结果的异质组合。汇总结果表明，MVPA 期间臭氧暴露对肺功能有不利影响（100% [95% CI 88-100]，p  < 0.001；高质量证据）和报告的症状（88% [95% CI 69 –96]，p  < 0.001；低质量证据）。MVPA 期间暴露于一氧化碳、二氧化氮、小型发动机尾气或柴油尾气对健康和运动相关结果的影响尚不确定，因为证据不足以及现有证据的确定性低至极低。

讨论

臭氧的证据是最强的，暴露于臭氧通常会导致肺功能下降和 MVPA 期间症状增加。与其他结果领域相关的研究仍然没有定论。尽管长期接触 AP 被证明是危险的，但健康个体在高（非臭氧）污染期间放弃 MVPA 的证据仍然很弱。

试用注册

于 2020 年 7 月 10 日在 PROSPERO (CRD42020188280) 进行追溯注册。