Effects of shift work on QTc interval and blood pressure in relation to heart rate variability

Objectives: There is evidence that shift work contributes to excess cardiovascular mortality. The purpose of this study was to determine the effects of shift work on heart rate-corrected QT (QTc) and blood pressure in relation to heart rate variability (CV_RR). Methods: The study population consisted of 153 male shiftworkers and 87 male day workers who were employed at a copper-smelting plant. The QTc interval, total power spectral density (t-PSD) of 100 RR intervals, PSDs with frequencies of 0.01 Hz–0.15 Hz and 0.15 Hz–0.40 Hz (PSD_LF and PSD_HF), CV_RR, low frequency (LF) component variability and high frequency (HF) component variability (CCV_LF and CCV_HF) and %LF (PSD_LF/(PSD_LF+PSD_HF) ·100) were measured (LF and HF components are thought to reflect the sympathetic and parasympathetic activities, respectively). Results: The QTc interval was significantly longer in the shiftworkers than in the day workers, although there was no significant difference in systolic or diastolic blood pressure between the two groups. Also, the CCV_LF and log(PSD_LF) were significantly depressed in the shiftworkers. In the day workers, the QTc interval was significantly related to the CV_RR, log(t-PSD), CCV_HF, log(PSD_HF),%LF, and log(LF/HF ratio) (partial correlation coefficient r=–0.305, –0.377, –0.312, –0.355, 0.297, and 0.277, respectively). In the shiftworkers only two relations of the QTc interval to non-specific CV_RR and log(t-PSD) were significant. Conclusion: The clear association between long QTc interval and reduced parasympathetic activity observed in the day workers did not exist in the shiftworkers. Rather, the shiftworkers had a selective reduction in sympathetic drive, which may have compensated for prolonged QTc interval due to shift work. On the other hand, the impact of shift work on hypertension remains unclear, although reduced sympathetic drive in the shiftworkers may explain the absence of differences in blood pressure between shiftworkers and day workers to some extent.     

冠心病患者窦性心率震荡及心率变异性的变化

目的 对冠心病患者窦性心率震荡（HRT）及心率变异性（HRV）指标进行分析,评价冠心病、冠脉病变与HRT、HRV的关系,以及两种指标的相关性.方法 选择经冠状动脉造影证实的冠心病患者103例（A组）,其中稳定性心绞痛（SAP）患者35例（A1组）、不稳定性心绞痛（UAP）患者28例（A2组）、急性心肌梗死（AMI）患者40例（A3组）与有室性期前收缩但无器质性心脏病患者30例为健康对照组（B组）,行常规24 h动态心电图检查,测定HRT指标（震荡起始TO及震荡斜率TS）及HRV各时域指标（SDNN、PNN50、HF）.结果 （1）A组各亚组TO值明显高于B组（-4.17±2.75、-3.16±3.18、-0.96±2.92;-6.30±3.47）,TS值明显低于B组（6.81±3.18、5.12±3.31、3.20±1.71;9.52±3.85）（P＜0.05 or P＜0.01）;A组各亚组HRV各时域指标（SDNN、PNN50、HF）值均明显低于B组（P＜0.05）;（2）在A1组中,TO与冠脉评分呈正相关;TS、SDNN、PNN50、HF与冠脉评分呈负相关,其中与TS相关性最强（r=0.45）;（3）TO与SDNN、PNN50、HF均呈负相关;TS与SDNN、PNN50、HF均呈正相关,其中与HF的相关性相对较强（r=0.47）.结论 （1）冠心病患者HRT现象变钝（TO值升高,TS值降低）,HRV各时域指标降低;（2）在预测冠脉病变严重程度上,HRT参数特别是TS相对HRV指标能更敏感地反映冠脉严重程度;（3）HRT与HRV参数间有相关性,其中TS与HF相关性较强.     

冠状动脉病变与心率变异性的关系

目的　研究冠心病 (CHD)患者冠状动脉不同病变程度与心率变异性 (HRV)的关系。方法　CHD组 31例 ,行选择性冠状动脉造影 (CAG)。正常对照组 2 7例。两组均行动态心电图监测 ,取得HRV时域和频域指标。结果　CHD组HRV各项指标均低于对照组 ,具有统计学意义。不同冠脉病变范围和程度HRV具有显著性差异。结论　CHD患者HRV明显下降。HRV能敏感地、定量地反映CHD患者冠状动脉病变程度。     

Occupational determinants of heart rate variability

Objectives: Analysis of HRV has been suggested as a way to study the effects of work-related stresses on cardiovascular autonomic regulation. The aim of this study was to evaluate the use of HRV in the investigation of work-related stressors. Methods: Cross-sectional data from an ongoing cohort study were used to analyse the relationship of the potential workplace stressors of job-strain, noise and shift work, with HRV. Mean HRV values during sleep and work were calculated in 135 24-h EKG recordings. Results: Shift workers displayed significantly decreased SDNNi levels during sleep, compared with those of the daytime workers (adjusted least square mean values: 69.3 and 85.8 ms, respectively, P < 0.05). Compared with the control group reporting low job demands and high work control (mean: 73.2), we found significantly elevated %LF means during work adjusted for sleep in the low demands, low control group (77.9, P < 0.01), high demands, high control group (77.7, P < 0.05) and high demands, low control group (77.7, P < 0.05). Workers reporting a high noise level compared with a low work noise level also displayed an elevated adjusted mean %LF during work (78.0 and 75.3 respectively, P < 0.06). Conclusions: The finding of a decreased SDNNi level during sleep in shift workers compared with day workers indicated a less favourable cardiovascular autonomic regulation, which may explain in part the excess cardiovascular disease risk in shift workers. The elevated %LF during work in employees exposed to high job strain or high noise levels indicated a direct shift in the autonomic cardiac balance towards sympathetic dominance. We concluded that the analysis of HRV may provide a useful tool in the study of the physiological effects of work-related stresses. Received: 22 July 1999 / Accepted: 4 December 1999     

Changes in melatonin and sex steroid hormone production among men as a result of rotating night shift work – the HORMONIT study

ObjectiveData from real world settings on circadian disruption and subsequent hormone-related changes may explain the higher risk of hormone-dependent cancers among night shift workers.The present study examines the melatonin and sex steroid hormone levels among night shift workers.MethodsWe included 44 male, rotating shift workers from a car factory in Spain, sampled both at the end of a 3-week night shift (22:00–06:00 hrs) and a 3-week early morning shift (06:00–14:00 hrs). Participants collected all urine voids over 24-hours during each shift. Urinary concentrations of sex steroid hormones (estrogens, androgens and progestogens) and 6-sulfatoxymelatonin (aMT6s, major melatonin metabolite) were determined. Individual cosinor analysis was used to derive the acrophase (peak time) and area under the curve (total production). Linear mixed models examined intraindividual associations between night shift work and log-transformed 24-hour peak time and total production of hormones compared to early morning shift work.ResultsThe acrophase was delayed during the night shift for aMT6s [geometric mean difference (GMD) 7.53 hrs, 95% confidence interval (CI) 4.46–10.60], androgens (eg, testosterone: GMD 6.83 hrs, 95% CI 0.34–13.32) and progestogens (eg, 17-hydroxyprogesterone: GMD 4.54 hrs, 95% CI 2.92–6.16) compared to the early morning shift. We found a higher production of adrenal androgen 11-oxoandrosterone/11-oxoetiocholanolone [geometric mean ratio (GMR) 1.43, 95% CI 1.12–1.81], and a lower production of adrenal progestogen 16-cysteinylprogesterone (GMR 0.79, 95% CI 0.67–0.93) during the night shift compared to the early morning shift levels.ConclusionsNight shift work was associated with melatonin and sex hormone-related changes in timing and total production, providing insight into the mechanistic path for its association with hormone-dependent cancer.     

Health risks related to shift work

Summary In an oil refinery with a labour force of 1260 male blue-collar workers, 300 matched cases of permanent shift workers, day workers, and drop-outs were selected and split into four groups corresponding in age and years at work.In terms of an overall score (health score, computed from data concerning absence due to sickness, morbidity, distribution and severity of diseases, and subjective complaints) health was found to deteriorate with age, but to a different degree in the shift and day workers.In shift workers, a steep decrease in score during the first years at work was followed by a continued slight decrease in middle age; from the age of 41 years onwards there was a further pronounced decrease in score. In day workers a stabilization in score was observed up to middle age, with a distinct decrease thereafter.The difference in health parameters between the groups was only small in younger workers (up to 12 years at work), but became striking and significant with increasing age. In the permanent shift workers an increasing health risk was clearly indicated by increases in absence due to sickness, gastro-intestinal and cardiovascular diseases and unspecific health complaints (sleep disturbances, premature fatigue). A specific kind of behaviour during illness (e.g. less readiness to consult a doctor) was also observed in the shift workers. In the permanent day workers health risks were not strictly age-related. Whereas absence due to sickness was highest in young workers, morbidity for respiratory diseases and injuries was significantly elevated in the older workers; the frequency of subjective complaints increased up to middle age and decreased thereafter.In drop-outs with considerable prior exposure to shift work, strikingly high rates of absence due to sickness and excess rates of cardiovascular diseases were observed.     

Comparison of heart rate variability and cardiac arrhythmias in polluted and clean air episodes in healthy individuals

Objective  

Pathophysiological mechanisms and pathways linking cardiovascular mortality and morbidity with air pollution were recently hypothesized. The present study evaluated association between air pollution and changes in heart rate variability as a marker of cardiac autonomic function in healthy individuals, and also determined the frequency of cardiac arrhythmias and QT interval changes on polluted compared to unpolluted days.     

儿童室性早搏的心率变异性分析

目的探讨良性和恶性室性早搏(VPB)儿童及健康儿童动态心电图的心率变异性(HRV),分析各时域指标和频域指标值变化。 方法选择2012年1月至2017年12月,于四川大学华西第二医院接受动态心电图检查,根据临床辅助检查和随访结果明确病因的6～14岁VPB儿童100例为研究对象。按照VPB的良、恶性,将其分为恶性VPB组(n＝50)及良性VPB组(n＝50)。恶性VPB组患儿均为合并器质性心脏病的VPB患儿,其中合并先天性心脏病患儿为4例、扩张型心肌病(DCM)为9例、心肌酶学检查结果异常而被诊断为病毒性心肌炎患儿为37例。选取同期于同一家医院接受动态心电图检查未见异常,并且一般临床资料均显示正常的儿童50例,纳入对照组。对于呈正态分布与方差齐性计量资料,如总体标准差(SDNN)、均值标准差(SDANN)、差值均方根(rMSSD)、差值>50 ms的百分比(PNN50)、R-R间期变异系数(CV),超低频功率(ULF)、极低频功率(VLF)、低频功率(LF)及高频功率(HF),采用±s表示,3组比较,采用单因素方差分析;进一步组间两两比较,采用最小显著差异法(LSD)法。受试儿性别构成比等计数资料采取率(%)表示,3组间比较,采用χ²检验。3组受试儿的性别构成比及年龄比较,差异均无统计学意义(P>0.05)。本研究符合2013年修订的《世界医学协会赫尔辛基宣言》要求,分组征得受试儿监护人的知情同意,并与之签署临床研究知情同意书。 结果3组受试儿的HRV时域指标SDNN、SDANN、rMSSD、PNN50、CV,频域指标ULF、VLF、LF、HF分别整体比较,差异均有统计学意义(F＝42.304、14.144、26.344、15.362、8.115,18.031、10.611、20.928、13.719, P<0.05)。进一步进行3组间两两比较的结果显示,恶性VPB组与良性VPB组CV、VLF、LF比较,差异均无统计学意义(P>0.05);良性VPB组与对照组PNN50、HF比较,差异均无统计学意义(P>0.05);其余HRV时域、频域指标3组间两两比较,差异均有统计学意义(P<0.05)。 结论儿童VPB的动态心电图HRV分析,对临床判断良、恶性VPB具有一定价值,但是否可作为判断儿童VPB严重程度及其预后的指标,则有待多中心、大样本、前瞻性随机对照试验进一步研究、证实。     

Association between sense of coherence and heart rate variability in healthy subjects

Objectives This report investigates whether there is any association between sense of coherence (SOC), as a coping measure in confronting stressful conditions, and heart rate variability (HRV), as a measure of the cardiac autonomic nervous system during the daily life pattern. Methods Sixteen healthy university students (14 males and 2 females) filled in the validated Japanese version of the SOC-13 questionnaire before being informed about the study protocol. For each participant, we calculated 5-minute HRV indices using logarithmically transformed data on frequency domains for HRV derived by 24-hour Holter monitoring. Frequency domains for HRV recordings were investigated for the 24-hour time periods. Results The correlation coefficient between the SOC scores and the high frequency power of HRV (0.15–0.40) was positively significant during the resting sitting position (r≥0.60, P<0.05). After grouping SOC scores by the median, the high frequency domain of HRV was higher in high SOC subjects for most of the 24-hour time period. Conclusion A higher SOC could modulate the parasympathetic tone of cardiac autonomic activity, especially during the resting sitting position.     

How to schedule night shift work in order to reduce health and safety risks

Objectives:This discussion paper aims to provide scientifically based recommendations on night shift schedules, including consecutive shifts, shift intervals and duration of shifts, which may reduce health and safety risks. Short-term physiological effects in terms of circadian disruption, inadequate sleep duration and quality, and fatigue were considered as possible links between night shift work and selected health and safety risks, namely, cancer, cardio-metabolic disease, injuries, and pregnancy-related outcomes.Method:In early 2020, 15 experienced shift work researchers participated in a workshop where they identified relevant scientific literature within their main research area.Results:Knowledge gaps and possible recommendations were discussed based on the current evidence. The consensus was that schedules which reduce circadian disruption may reduce cancer risk, particularly for breast cancer, and schedules that optimize sleep and reduce fatigue may reduce the occurrence of injuries. This is generally achieved with fewer consecutive night shifts, sufficient shift intervals, and shorter night shift duration.Conclusions:Based on the limited, existing literature, we recommend that in order to reduce the risk of injuries and possibly breast cancer, night shift schedules have: (i) ≤3 consecutive night shifts; (ii) shift intervals of ≥11 hours; and (iii) ≤9 hours shift duration. In special cases – eg, oil rigs and other isolated workplaces with better possibilities to adapt to daytime sleep – additional or other recommendations may apply. Finally, to reduce risk of miscarriage, pregnant women should not work more than one night shift in a week.     

心率变异功率谱检测技术

本文报导一种研究心率变异（ＨＲＶ）功率谱分析技术，可用于无创伤性定量测定心脏植物神经活动。通过对连续心电信号的Ｒ－Ｒ间期检测，应用快速傅里叶变换计算ＨＲＶ功率谱，并采用分段平均和窗口技术以降低有限数据对结果的影响，使谱线光滑。     

Heart rate during work and heart rate variability during the following night: a day-by-day investigation on the physical activity paradox among blue-collar workers

Objectives:Contrary to leisure-time physical activity, occupational physical activity (OPA) may have harmful health effects, called the physical activity paradox. A proposed mechanism is that OPA can elevate the heart rate (HR) for several hours per day. We aimed to investigate the association between the mean intensity of OPA and HR variability (HRV) indices the following night.Methods:Three cohorts (NOMAD, DPhacto, and Physical Workload and Fitness) involving blue-collar workers from different sectors were merged in this study. HR monitors (Actiheart) recorded 24-hour inter-beat intervals (IBI) for up to four consecutive days. The relative intensity of the mean HR during work was estimated by HR reserve (%HRR), and time-domain indices of HRV were analyzed during the following night. Data were analyzed using a multilevel growth model to test the association between mean %HRR during work and HRV indices at night in a day-by-day analysis adjusted for age, BMI, alcohol consumption, smoking, and occupation.Results:The dataset included a sample of 878 Danish blue-collar workers, with a mean %HRR during work of 31%, and 42% worked at an intensity ≥30%HRR. The multilevel model showed negative within- and between-subject associations between %HRR during work and HRV indices at night.Conclusions:Our results indicate a higher %HRR during work to associate with lower HRV indices the following night and a higher HR, reflecting an imbalanced autonomic cardiac modulation. This finding supports a high mean HR during work to be a potential underlying mechanism for the harmful health effect of OPA.     

成人超重和肥胖的危害及影响因素分析

  目的  了解中国医科大学附属盛京医院女性倒班从业护士群体超重、肥胖现况。  方法  收集2017年中国医科大学附属盛京医院医护人员春季体检大数据,选择她们中从事临床外科倒班制女性护理人员537人（倒班护理组）,常年从事白班护理工作女性护士102人（对照组）。比较2组入选对象与超重、肥胖相关体检测量指标。  结果  2组对象超重及肥胖数据比较中,倒班护士组的超重例数（115）例、超重率（21.42）%、肥胖例数（89）例及肥胖率（16.57）%均明显高于对照组（均P < 0.05）。不同年龄、工作年限倒班护士超重及肥胖数据比较中, 31～40岁组的超重例数、超重率、肥胖例数及肥胖率均明显高于 ≤ 30岁组（均P < 0.05）,≥ 5年组的超重例数、超重率、肥胖例数及肥胖率均明显高于 < 5年组（均P < 0.05）。  结论  一线女性倒班从业护士群体超重、肥胖现况不容乐观,且随增龄和从业时间延长而趋于严重,应制定有针对性的预防、干预计划。     

Heart rate patterns in sedentary shift work: influence of circadian rhythm,meals and personality

Summary Heart rate was recorded at regular intervals during the course of 8-h sessions of simulated sedentary shift work performed for 12 consecutive days. Separate groups of subjects were assigned to one of three shifts, commencing either at 0400 hours (morning shift), 0800 hours (day shift) or 2200 hours (night shift). A major meal was taken during a break in the middle of each shift. In all groups heart rate fell during the pre-break period, but rose after the break in response to the meal. This pattern remained constant over the 12-day period in the morning and day shift groups, but in the night shift group a progressive rise in the general level of the readings, caused mainly by the adjustment of the circadian rhythm to the altered sleeep/wake cycle, was accompanied by systematic changes in the extent of both the pre-break fall and the post-meal rise. Comparison with the results of a control study of 24-h variation in base heart rate suggested that differential responses to the meal observed in the three shift groups may have been due, at least in part, to differences in their personality make-up. It is concluded that, although systematic patterns of heart rate can be observed in sedentary shift work, both the timing of the shift and the personality of the subject must be taken into account when assessing the changes in physiological state likely to occur during work sessions that include a major break for refreshment.Dedicated to Professor J. Rutenfranz on the occasion of his 60th birthday     

老年糖尿病合并高血压患者心率变异性变化的研究

目的：探讨老年糖尿病合并高血压患者心率变异性的变化及临床意义。方法：对63例老年糖尿病合并高血压患者（分为不伴有LVH组和伴有LVH组），分别与对照组进行频域指标分析对比。结果：糖尿病合并高血压不伴LVH和LF，LF／HF比值明显升高，HF降低，差异显著；同时糖尿病合并高血压伴有LVH组各项指标变化更为明显（P〈0．01）。结论：老年糖尿病合并高血压患者心率变异性变化比健康老年人变化更为明显，HRV有助于心脏自主神经病变的早期发现和早期诊断。     

基于三种信号处理方法的心率变异性分析系统

介绍了三种信号处理方法的心率变异性分析系统，此分析系统以5min-20min心率数据进行分析，采用心率变异性的时域分析、频域分析和非线性动力学分析技术，分析参数达24个。采用BorlandC 语言编程，人机界面全部汉字化，适合基础研究和临床应用。