Associations of\nPersonal Hourly Exposures to Air Temperature\nand Pollution with Resting Heart Rate in Chronic Obstructive Pulmonary\nDisease

Previous studies linked higher daily ambient air temperature\nand\npollution with increased cardiorespiratory morbidity, but immediate\neffects of personal, hourly exposures on resting heart rate remained\nunclear. We followed 30 older former smokers with chronic obstructive\npulmonary disease (COPD) in Massachusetts for four nonconsecutive\n30-day periods over 12 months, collecting 54,487 hourly observations\nof personal air temperature, fine particulate matter (PM<sub>2.5</sub>), nitrogen dioxide (NO<sub>2</sub>), ozone (O<sub>3</sub>), and\nresting heart rate. We explored the single lag effects (0–71\nh) and cumulative effects (0–5\nh, the significant lag windows) of air temperature and pollution on\nresting heart rate using generalized additive mixed models with distributed\nlag nonlinear models. Single lag effects of higher air temperature\nand pollutants on higher resting heart rate were most pronounced at\nlag 0 to 5 h. Cumulative effects of higher air temperature, PM<sub>2.5</sub>, O<sub>3</sub>, and NO<sub>2</sub> (each interquartile\nrange increment) on higher resting heart rate at lag 0–5 h,\nshow differences of (beats per minute [bpm], 95% CI) 1.46 (1.31–1.62),\n0.35 (0.32–0.39), 2.32 (2.19–2.45), and 1.79 (1.66–1.92),\nrespectively. In conclusion, higher personal hourly air temperature,\nPM<sub>2.5</sub>, O<sub>3</sub>, and NO<sub>2</sub> exposures at lag\n0–5 h are associated with higher resting heart rate in COPD\npatients.