Influence of Weather and Atmospheric Pollution on Physical Activity in Patients With COPD

Ayedh D. Alahmari; Alex J. Mackay; Anant R.C. Patel; Beverly S. Kowlessar; Richa Singh; Simon E. Brill; James P. Allinson; Jadwiga A. Wedzicha; Gavin C. Donaldson

Disclosures

Respiratory Research. 2015;16(71) 

In This Article

Abstract and Introduction

Abstract

Rationale: Information concerning how climate and atmospheric pollutants affects physical activity in COPD patients is lacking and might be valuable in determining when physical activity should be encouraged.

Methods: Seventy-three stable COPD patients recorded on daily diary cards worsening of respiratory symptoms, peak expiratory flow rate, hours spent outside the home and the number of steps taken per day. Pedometry data was recorded on 16,478 days, an average of 267 days per patient (range 29–658). Daily data for atmospheric PM10 and ozone (O3) were obtained for Bloomsbury Square, Central London from the Air Quality Information Archive databases. Daily weather data were obtained for London Heathrow from the British Atmospheric Data Archive.

Results: Colder weather below 22.5 °C, reduced daily step count by 43.3 steps day per°C (95 % CI 2.14 to 84.4; p = 0.039) and activity was lower on rainy than dry days (p = 0.002) and on overcast compared to sunny days (p < 0.001). Daily step count was 434 steps per day lower on Sunday than Saturday (p < 0.001) and 353 steps per day lower on Saturday than Friday (p < 0.001). After allowance for these effects, higher O3 levels decreased activity during the whole week (-8 steps/ug/m3; p = 0.005) and at weekends (-7.8 steps/ug/m3; p = 0.032). Whilst, during the week PM10 reduced activity (p = 0.018) but not during the weekend.

Conclusions: Inactivity of COPD patients is greatest on cold, wet and overcast days and at the weekends. This study also provides evidence of an independent effect of atmospheric pollution at high levels.

Introduction

Chronic obstructive pulmonary disease (COPD) causes much morbidity and reduces quality of life.[1] The disease is projected to become the fourth leading cause of death worldwide by 2030.[2] COPD involves airflow obstruction that results in dyspnoea which is associated with reduced daily activity and increased muscle weakness.[3]

Patients with COPD experience episodes of acute worsening of in their respiratory symptoms termed exacerbations that are often triggered by respiratory infection.[1,4] Frequent exacerbations have an accelerated decline in lung function[5] and an increase rise in airway and systemic inflammation.[6,7] Patients with frequent exacerbations patients also becoming housebound faster[8] and have greater perception of fatigue[9] which might explain why this group suffers more from depression.[10] We have previously reported that physical activity is reduced during a COPD exacerbation.[11] In this study, we report only on data collected when the patients were clinically stable.

A few studies have examined activity in older people[12,13] but we are unaware of any studies that have specifically examined the impact of daily weather on physical activity in patients with COPD.

Pollution may also reduce activity and we have previously reported that particulate matter <10 μm in diameter (PM10) in London increases symptoms of dyspnoea in COPD patients[14] and reduce pulmonary function.[15] Traffic-related air pollution exposure has also been shown to be positively associated with first hospital admission for COPD.[16]

Maintenance of physical activity can substantially reduce age-related mortality[12] but it is particularly important for patients with COPD since those who continued to exercise have less dyspnoea, fewer hospital admissions for COPD and reduced mortality. Indeed, COPD patients can be referred by physicians to specialized pulmonary rehabilitation clinics to undergo a few weeks of physical training and education but poor participation and a failure to continue exercising limits the effectiveness of this intervention. There is a need therefore to understand the barriers to participation and sustained behaviour change.[17] In this study, we examine for the first time in patients with COPD how the weather and atmospheric pollution levels affect physical activity.

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