Short-term effects of weather and air pollution on physical activity in COPD patients

Abstract

<b>Aim:</b> To assess the short-term (daily) association of air pollution and weather with physical activity in COPD patients. We studied 407 COPD patients (85% men, 68 (9) years, FEV₁ 57 (18) %pred, 6MWD 486 (95) m) from a multi-center study in Catalonia (Spain) that provided daily physical activity records (steps, time in moderate-to-vigorous physical activity, sedentary time, locomotion movement intensity) for two 7-day campaigns one year apart, using the Dynaport MoveMonitor. We applied a spatiotemporal assessment to obtain weather (temperature, rainfall, daylight duration, solar radiation) and air pollution (NO₂, PM₁₀, PM_2,5ABS) exposure during 7 periods of 24 h (lags 0-6) prior to the physical activity record. Mixed-effect linear regression models were adjusted for weekday, season, age, sex and social class with patient and city as random effects. Higher average and maximum temperature at lags 0-1, solar radiation at lag 1 and daylight duration at all lags were significantly associated with more steps (Figure 1). Higher rainfall on the same day was related to less steps. Higher PM₁₀ and PM_2,5ABS levels were associated to less steps at lags 3-4. Similar results were shown for moderate-to-vigorous and sedentary time. No associations were observed for NO₂ exposure nor with physical activity intensity. Daily physical activity of COPD patients is influenced by the weather of the same day and air pollution levels of previous days.