The Autonomic Nervous System Functions in Integrated Circuit Design Company Employees during Different Working Time

Abstract

The purpose of this study was to investigate the autonomic nervous system functions in integrated circuit design company employees during different working time by analyzing heart rate variability (HRV).The participants were twenty-six company employees aged between 23 and 44 years (mean: 34 years) that divided into two groups. The morning group was measured two minutes photoplethysmography (PPG) between eight thirty to nine thirty A.M.. The afternoon group was measured PPG between five thirty to six thirty P.M.. The peak-to-peak interval of heart pulse signals were analyzed using power spectral analysis to quantify the time and frequency domain properties of heart rate variability. Comparisons the HRV indices of two groups were performed with the Mann-Whitney U-test.There was no significant difference between the mean age of two groups. Comparison of the quantitative heart rate variability measures of two groups revealed that the high frequency power (HFP), low frequency power (LFP), total power (TP) and standard deviation of normal intervals (SDNN) were significantly lower in afternoon group, compared with morning group (p<0.05).HRV analysis showed that both cardiovascular sympathetic (LFP) and parasympathetic (HFP) nervous system had decreased significantly by eight hours working. The TP and SDNN of heart rate variability is well known to be representative of the entire autonomic nervous system (ANS) activity of the heart, and hence our results suggest that the entire ANS function will withdrawal after hard working. Reduced ANS activity may be a consequence of work stress and fatigue. There are a lot of link from the condition of reduced HRV to cardiovascular disease. Therefore, these findings suggest that the HRV analysis should be used to assess the ANS function and the risk of cardiovascular disease in the employees of longterm working on computer.KeywordsAutonomic nervous systemHeart rate variabilityEmployeesWithdrawal