Acute Changes in Heart Rate Variability in Subjects With Diabetes Following a Highway Traffic Exposure

Abstract

OBJECTIVE: To pilot a protocol to evaluate acute cardiovascular effects in in-vehicle exposure to traffic air pollutants in people with diabetes. METHODS: Twenty-one volunteers with type 2 diabetes were passengers on 90- to 110-minute car rides on a busy highway. We measured in-vehicle particle number and mass (PM2.5) nitrogen dioxide, and carbon monoxide and heart rate, heart rate variability (HRV), and blood pressure. RESULTS: Compared with pre-ride measurements, we found a decrease in high frequency (HF) HRV from pre-ride to next day (ratio 0.66, 95% CI = 0.47 to 0.93) and an increase in low frequency to HF ratio at post-ride (ratio 1.92, 95% CI = 1.21 to 3.05) at post-ride. Interquartile range increases in measured pollutants were associated with next-day decreases in HR HRV. CONCLUSIONS: This protocol appears useful for assessing acute adverse cardiovascular effects of in-vehicle exposures among people who have diabetes.