Heart Rate Variability in Occupational Health ―A Systematic Review

Abstract

BackgroundCardiovascular disease (CVD) is the leading cause of mortality and morbidity in industrialized countries 1) . In a working population, occupational factors are believed to pose a threat to workers' cardiovascular health. Substantial research has shown that adverse physical and psychosocial work environments and working conditions, such as shift work and excessive workload, are related to CVD. To examine the acute and chronic effects of such work-related factors on the cardiovascular system, cardiac autonomic nervous system activity during work and rest has been assessed by heart rate variability (HRV).Heart rhythm is recorded by electrocardiography. The measured signal shows a series of waves that present electrical events in the four chambers and the conduction pathways within the heart. The time interval between consecutive R waves that correspond to the contraction of the ventricles is called the RR interval (RRI). HRV is a time series of RRIs that fluctuate beat by beat in healthy humans because of time-to-time changes in activities of sympathetic and parasympathetic nerves innervating to the sinus node.HRV is generated in part by periodic inputs of both respiration and blood pressure variability into the medullary cardiovascular centers 2) . These periodic modulations are clearly identified within the power spectrum of HRV as peaks at the respiratory frequency (≈ 0.25 Hz) and at the frequency of the well-known Mayer wave (0.1 Hz) in blood pressure variability 1,3) .Heart rate increases and decreases during inspiration and expiration, respectively. This is mainly caused by the physiological fact that parasympathetic output from the cardiovascular center is inhibited during inspiration 4) . Respiratory rhythm during rest is about 0.25 Hz. Therefore, exposure to occupational toxicants and hazardous environments), psychosocial workload (i.e. job stressors), and working time (i.e. shift work) had been examined and identified as having associations with low HF power. These findings may indicate that research into parasympathetic nervous system activity should be focused to protect cardiovascular health at work. We also propose the use of very low and ultralow frequency HRV components in autonomic research for workers' health.

Different Exercise Behaviors Influence Heart Rate Variability, Autonomic Nerve System Function and Menopausal Symptoms in Post-Menopausal Women

“…Heart rate variability (HRV) is a highly reliable predictor of cardiovascular diseases and is an assessment tool of heart function 5) . The adjustment of the autonomic nervous system (ANS) involves the balance of sympathetic and parasympathetic nerve activity and can represent changes in psychological status 6) .…”

Heart rate variability and endothelial function after sleep deprivation and recovery sleep among male shift and non-shift workers

“…One field study has shown lower FMD among experienced shift workers (19). By contrast, HRV has been assessed more frequently in field studies of shift workers (20) with studies predominantly showing a shift in the sympathetic/parasympathetic balance. It is not known, however, what aspects of shift work are causative.…”

A Method to Reveal Workload Weak-Resilience-Signals at a Rail Control Post

“…We build upon this theory to compose XTL. We use the Integrated Workload Scale (IWS) [6] to measure subjective load and the extensively-researched heart rate variability (HRV) to identify physiological arousal due to workload change [7][8][9][10][11][12]. In the next sections, we elaborate these measures in more detail for the setting described above.…”

“…HRV can be calculated in various ways roughly divided in time domain methods and frequency domain methods [11]. We use the most common occupational health method [12]: SDNN, the standard deviation (SD) of all normal-to-normal (NN) intervals, from the time domain and the low-high frequency (LF/HF) ratio in the frequency domain. We calculate both measures in the same 5 min base-slot used for the calculation of XTL and IWS.…”

“…We expect the HRV to decline during a stretch as evidence that a growing IWS is an expression of a growing mental load. [12] The XTL components are used to show the workload distribution among the members of each group R and T. The standard deviation (SD) presents the work distribution for each of the activities (for an example, see Fig. 6).…”