Background We conducted a cohort study to evaluate the effectiveness of heart rate variability (HRV) to assess for the 5 year risk CVD event. The aim of our study is to find the association between HRV indices and the risk factors of reduced HRV, the association between HRV indices and CVD.

Methods The Taiwan Bus Driver Cohort Study recruited 1650 professional drivers from a large bus company in Taiwan since 2005. We only selected professional drivers whose total driving period exceeded 100 days during the 3 years. The remaining 1149 drivers completed the survey.

Results We found drivers whose driving duration more than 8 years showed the lowest risk of CVD (HR: 0,25, 95% CI 0,12 to 0,51, p<0.001). Drivers who had the drinking habits had higher CVD risk (HR: 2,19, 95% CI 1,38 to 3,50, p=0,038). BMI, SBP, DBP, Total cholesterol, Triglycerides were significantly associated with decreased HRV variables. When we compare HRV components between subjects with CVD and non-CVD group, decreased LF is found in CVD group (p=0.028), especially for hypertensive disease (p=0.039).

Conclusions This study concludes that among several HRV indices LF is an independent predictor of CVD. Moreover, there is much overlap in modifiable biological risk factors between reduced HRV and CVD. Therefore, we need to find whether a factor affect reduced HRV more or CVD risk more. Further research should be conducted regarding measures to change the modifiable risk factors of reduced HRV, and to investigate whether these interventions could reduce CVD risk in professional drivers.