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Background: Both low vagally-mediated heart rate variability (HRV) and depression have been shown to be risk factors for cardiovascular disease (CVD). We recently identified an HRV cutpoint below which persons have an increased risk for several cardiometabolic disorders. However, no cutpoint exists to identify those at risk for depression., Methods: The association between daytime HRV and diagnostically validated depression cutoffs using the five-item World Health Organization Well-being Index (WHO-5) was examined in adults from the Mannheim Industrial Cohort Study (n = 9973; M age  = 41.9[10.9]; 20 % women [n = 1934]). The aim was to identify HRV cutpoints for individuals who may have clinical depression., Results: Regression adjusting for age, sex, and linear trend showed a significant quadratic association between depression, indexed by WHO-5 scores and HRV, indexed by the root mean square successive differences (RMSSD) in milliseconds (ms) (p < 0.001). Logistic regression models adjusting for age, sex, and heart period (i.e., inter-beat intervals) compared the clinically depressed (WHO-5 ≤ 28) and those with a screening diagnosis of depression (WHO-5 ≤ 50) to the rest of the population. Significant odds ratios suggested two RMSSD values 25 ± 2 ms (OR = 1.39 [1.17, 1.64]) and 35 ± 2 ms (OR = 1.17 [1.02, 1.34]) that may be used to identify those with an elevated risk for depression., Limitations: The sample was primarily German men. Fitness and anti-depressant use were not available., Conclusions: As HRV is a brief measure that can be used in clinical settings, our HRV cutpoints have implications for the early detection of those at risk for psychological and cardiometabolic disorders., Competing Interests: Declaration of competing interest The authors declare that there are no financial/personal interests or beliefs that could affect their objectivity and that no potential competing interests exist., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Objective: Vagus nerve functioning, as indexed by high-frequency heart rate variability (HF-HRV), has been implicated in a wide range of mental and physical health conditions, including sleep complaints. This study aimed to test associations between HF-HRV measured during sleep (sleep HF-HRV) and subjective sleep complaints 4 years later., Methods: One hundred forty-three healthy employees (91% male; MAge = 47.8 years [time 2], SD = 8.3 years) of an industrial company in Southern Germany completed the Jenkins Sleep Problems Scale, participated in a voluntary health assessment, and were given a 24-hour ambulatory heart rate recording device in 2007. Employees returned for a health assessment and completed the Jenkins Sleep Problems Scale 4 years later., Results: Hierarchical regression analyses showed that lower sleep HF-HRV measured in 2007 was associated with higher self-reported sleep complaints 4 years later after controlling for covariates (rab,c = -0.096, b = -0.108, 95% CI, -0.298 to 0.081, ΔR2 = 0.009, p = .050)., Conclusions: These data are the first to show that lower sleep HF-HRV predicted worse sleep 4 years later, highlighting the importance of vagus nerve functioning in adaptability and health., (Copyright © 2024 by the American Psychosomatic Society.)

Objectives: The present study sought to expand upon prior investigations examining patterns of vagally mediated heart rate variability (vmHRV) and perceived exertion as a function of body mass index (BMI) in response to and recovery from exercise., Methods: Participants underwent a resting (baseline) period, followed by a graded exercise protocol on an ergometer with ascending difficulty stages, and finally another resting (recovery) period. Individuals were stratified into three BMI groups: low, moderate, and high., Results: Individuals in the high BMI group exhibited a significantly greater decrease in vmHRV from baseline to graded exercise in comparison to the moderate BMI group. Individuals in the high BMI group also showed significantly lower vmHRV at recovery compared with baseline than individuals with moderate BMI; indicating that the high BMI group's vmHRV did not recover to the degree of those in the moderate BMI group. No significant results regarding vmHRV were found in the low BMI group. Of note, BMI and perceived exertion during the recovery period were positively associated. Results also showed a significant negative association between vmHRV and perceived exertion at each grade of exercise. There was no significant association between vmHRV and perceived exertion during baseline or recovery., Conclusions: This report extends prior research studying BMI and patterns of vmHRV reactivity in the domain of physical exercise. Our data contribute to previous reports suggesting that high BMI can lead to maladaptive patterns of vmHRV reactivity to and recovery from physical exercise., (© 2018 Wiley Periodicals, Inc.)

Background: Depressed adults are more likely to become nicotine dependent and smokers are at increased risk for depression. Smoking and depression are each associated with inflammation and vagal tone., Purpose: The purpose of this study is to determine as to what extent the association between depression and smoking is mediated by inflammation and/or vagal tone., Methods: We studied a cross-sectional occupational sample (n = 647) with information on the number of cigarettes smoked per day and depression (as measured by the Hospital Anxiety and Depression Scale). Heart rate variability, an indicator of vagal tone, was measured by electrocardiographic recordings. Inflammatory markers included C-reactive protein, white blood cells, and fibrinogen. Linear regression was employed along with the Freedman-Schatzkin test to assess mediation., Results: We observed a positive association between depression and smoking (p < 0.05). Vagal tone and fibrinogen were found to weakly attenuate this association., Conclusion: These are the first data to demonstrate that the association between depression and smoking may partially be mediated by vagal tone and fibrinogen.

Objective: Previous research has suggested that the association between work stress and heart disease is more pronounced in young than in old employees. Similar age specificity may apply to the relation between work stress and heart rate variability (HRV), but data on this issue is sparse. We aimed to assess the age-specificity of the work stress-HRV association in greater detail., Methods: We used cross-sectional data from an occupational cohort (n=591) from Germany. Work stress was assessed using the job content and the effort-reward-imbalance (ERI) questionnaires. HRV was recorded over 24 h and was divided into three periods of the day (work time, leisure time, sleep time). Partial correlation coefficients (PCCs) were calculated for four age groups (17-34, 35-44, 45-54, and 55-65 years). Further, multilevel growth curve models (GCM) were run to examine whether age may modify potential work stress-HRV associations in a non-linear fashion., Results: Job strain and HRV were unrelated in either analytical approach and this association was not modified by age. In contrast, using PCCs ERI was only related to HRV during work (PCC=-0.231, P<.01) and leisure time (PCC=-0.195, P<.05) in employees aged 35-44. Multilevel GCM models confirmed this finding., Conclusion: The inverse association between work stress as measured by ERI and HRV appears to be most pronounced in workers aged 35-44. These findings may partly be explained by age-dependent HRV declines, age-related differences in career attitudes or increased susceptibility among those aged 35-44 due to facing multiple different stressors at the same time., (Copyright 2010 Elsevier Inc. All rights reserved.)

Background: Elevated plasma fibrinogen levels have prospectively been associated with an increased risk of coronary artery disease in different populations. Plasma fibrinogen is a measure of systemic inflammation crucially involved in atherosclerosis. The vagus nerve curtails inflammation via a cholinergic antiinflammatory pathway. We hypothesized that lower vagal control of the heart relates to higher plasma fibrinogen levels., Methods: Study participants were 559 employees (age 17-63 years; 89% men) of an airplane manufacturing plant in southern Germany. All subjects underwent medical examination, blood sampling, and 24-hour ambulatory heart rate recording while kept on their work routine. The root mean square of successive differences in RR intervals during the night period (nighttime RMSSD) was computed as the heart rate variability index of vagal function., Results: After controlling for demographic, lifestyle, and medical factors, nighttime RMSSD explained 1.7% (P = 0.001), 0.8% (P = 0.033), and 7.8% (P = 0.007), respectively, of the variance in fibrinogen levels in all subjects, men, and women. Nighttime RMSSD and fibrinogen levels were stronger correlated in women than in men. In all workers, men, and women, respectively, there was a mean +/- SEM increase of 0.41 +/- 0.13 mg/dL, 0.28 +/- 0.13 mg/dL, and 1.16 +/- 0.41 mg/dL fibrinogen for each millisecond decrease in nighttime RMSSD., Conclusions: Reduced vagal outflow to the heart correlated with elevated plasma fibrinogen levels independent of the established cardiovascular risk factors. This relationship seemed comparably stronger in women than men. Such an autonomic mechanism might contribute to the atherosclerotic process and its thrombotic complications.