The correlations between air quality and heart rate variability in aged susceptible people during Beijing Olympic Games 2008

OBJECTIVE: To observe the variations of the concentrations of air pollutants and explore the correlation between the heart rate variability (HRV) of the aged people and the air quality during Beijing Olympic Games 2008. METHODS: A panel study design was adopted. A total of twenty-six over 55-year-old patients with coronary heart disease or angina pectoris or a symptom of myocardial ischemia at least for one year were enrolled as a panel and followed up five times by measuring HRV index and other related indexes from June to September in 2008. The correlations between the HRV of the aged people and the air quality was analyzed with the linear mixed-effect models according to the data of air pollutants and meteorological conditions collected simultaneously from Beijing Environmental Protection Bureau and Beijing Meteorological Bureau. RESULTS: In single-pollutant mixed-effect models, the significant correlation was observed in the reduction of ambient PM(10), SO(2) and NO(2) with the improvement of the total power and high-frequency power (HF) of HRV in the panel subjects, and a 10 microg/m(3) decrease in PM(10), SO(2) and NO(2) level was correlated with 2.51% (95%CI: -3.80% - -1.22%, t = -1.99, P = 0.0497), 31.39% (95%CI: -52.24% - -10.53%, t = -1.99, P = 0.0497) and 42.72% (95%CI: -75.06% - -10.38%, t = -1.99, P = 0.0497) rises in total power of HRV respectively. A 10 microg/m(3) decrease in PM(10), SO(2) and NO(2) level was correlated with 3.46% (95%CI: -5.14% - -1.77%, t = -2.11, P = 0.0378), 40.63% (95%CI: -68.70% - -12.56%, t = -2.11, P = 0.0378) and 53.76% (95%CI: -97.97% - -9.56%, t = -2.11, P = 0.0378) rises in high-frequency power (HF) of HRV respectively. CONCLUSION: It suggests that the air pollution reduction could improve the cardiovascular functions of the susceptible population.