Heart Rate Variability among Long Distance Bus Drivers after a Night Shift

Most of the fatal accidents were found to be due to fatigue among the drivers. Long distance bus drivers are more prone to fatigue following driving and hence increase in the risk of road traffic accident among them. Techniques such as Electroencephalography (EEG), Electrooculography (EOG) and Electrocardiography (ECG) were used to detect fatigue among the drivers during and after driving. Heart rate variability (HRV) assessment in drivers was found to be a useful tool to detect fatigue and drowsiness. Data on HRV and fatigue among bus drivers post night shift is scarce in the literature.

HRV was assessed during resting state among 12 long-distance bus drivers immediately after their night shift. HRV was also assessed among non-bus drivers who were not involved in shift works. Obese, Hypertensive and diabetic patients were excluded from the study. Time domain and frequency domain measures of HRV were compared between bus drivers and non bus drivers.

Baseline heart rate and blood pressure were normal in both the groups. All the time domain and frequency domain measures were found to be normal in both the groups. Though time domain measures such as SDNN, rMMSSD, NN50, pNN50 were increased and frequency domain measures such as LFnu and LF/HF ratio were decreased in study group, they were not statistically significant.

There seems to be an increase in parasympathetic activity among long-distance bus drivers probably due to fatigue because of prolonged driving overnight.