Heart Rate Variability Research Articles

A multimodal deep learning-based algorithm for specific fetal heart rate events detection.

This study aims to develop a multimodal deep learning-based algorithm for detecting specific fetal heart rate (FHR) events, to enhance automatic monitoring and intelligent assessment of fetal well-being. We analyzed FHR and uterine contraction signals by combining various feature extraction techniques, including morphological features, heart rate variability features, and nonlinear domain features, with deep learning algorithms. This approach enabled us to classify four specific FHR events (bradycardia, tachycardia, acceleration, and deceleration) as well as four distinct deceleration patterns (early, late, variable, and prolonged deceleration). We proposed a multi-model deep neural network and a pre-fusion deep learning model to accurately classify the multimodal parameters derived from Cardiotocography signals. These accuracy metrics were calculated based on expert-labeled data. The algorithm achieved a classification accuracy of 96.2 % for acceleration, 94.4 % for deceleration, 90.9 % for tachycardia, and 85.8 % for bradycardia. Additionally, it achieved 67.0 % accuracy in classifying the four distinct deceleration patterns, with 80.9 % accuracy for late deceleration and 98.9 % for prolonged deceleration. The proposed multimodal deep learning algorithm serves as a reliable decision support tool for clinicians, significantly improving the detection and assessment of specific FHR events, which are crucial for fetal health monitoring.

Temporal inequality of RR intervals like a new psychophysiological indicator of mental stress

Introduction: Gini coefficient (Gini index or Gini ratio) is a parameter that is normally used in economy to measure the income distribution in a country or in the whole wide world, but it can be used to measure any kind of distribution. In the present study it is exposed an innovative proposal of application of the Gini coefficient to Heart Rate Variability (HRV) like a psychophysiological indicator of mental stress.Objective: to assess the application of the Gini coefficient as a psychophysiological indicator of mental stress.Methods: a non-observational crossover study, carried out in the biomedical laboratory of the Medical University of Santiago de Cuba. The involved participants are 13 healthy individuals (age 19 ± 1,5 years). Heart rate was continuously recorded at rest (5 minutes) and during a mental stress (5 minutes). Linear and nonlinear methods of heart rate variability were assessed, and 2 new indicators (Sequential and Non-Sequential Gini) were calculated and proposed to measure HRV differences between states.Results: when comparing rest and mental stress conditions, a sensible decrease of the traditional indicators of the HRV was founded (p<0,05), an increase of the heart rate (p=0,004) and of the Sequential Gini (p=0,004) and Non-Sequential Gini (p=0,04).Conclusions: the results suggest that temporary inequality of the RR intervals analyzed from the Gini coefficient could be an adequate indicator of sympathetic activity present during the mental stress

The Importance of Including Psychophysiological Methods in Psychotherapy.

This paper describes characteristics of sophisticated use of psychophysiological therapy procedures and describes a scoping review of evidence that adding psychophysiological procedures to psychotherapy improves outcome. It also reviews literature describing comparisons between psychophysiological procedures and various CBT and other verbal psychotherapy procedures when used as monotherapies. Some details of progressive muscle relaxation, autogenic training, and biofeedback are described that often are omitted in standard clinical training, including the method of diminishing tensions and differential relaxation training in progressive muscle relaxation, use of autogenic discharges and hypnotic instructions in autogenic training, and resonance frequency training in heart rate variability biofeedback and slow breathing. Although these details are often also missing in outcome studies, tentative conclusions can still be drawn from the empirical literature. As a monotherapy, psychophysiological methods are generally as powerful as verbal psychotherapies, although combining them with psychotherapy yields a larger effect than either approach alone. Psychophysiological methods have their strongest effects on anxiety and depression, with weaker effects for panic and PTSD, particularly when compared with exposure therapy, although the latter comparisons were restricted to relaxation training as a psychophysiological approach. Effects of psychophysiological interventions are weaker among elementary school children than among adults and adolescents. The results suggest that psychophysiological methods should be used along with other psychotherapeutic interventions for greatest effect.

Exercise intensity measurement using fractal analysis of heart rate variability: Reliability, agreement and influence of sex and cardiorespiratory fitness.

The study aimed to establish the test-retest reliability of detrended fluctuation analysis of heart rate variability (DFA-α1) based exercise intensity thresholds, assess its agreement with ventilatory- and lactate-derived thresholds and the moderating effect of sex and cardiorespiratory fitness (CRF) on the agreement. Intensity thresholds for thirty-seven participants (17 females) based on blood lactate (LT1/LT2), gas-exchange (VT1/VT2) and DFA-α1 (αTh1/αTh2) were assessed. Heart rate (HR) at αTh1 and αTh2 showed good test-retest reliability (coefficient of variation [CV] < 6%), and moderate to high agreement with LTs (r = 0.40 - 0.57) and VTs (r = 0.61 - 0.66) respectively. Mixed effects models indicated bias magnitude depended on CRF, with DFA-α1 overestimating thresholds versus VTs for lower fitness levels (speed at VT1 <8.5 km⋅hr-1), while underestimating for higher fitness levels (speed at VT2 >15 km⋅hr-1; VO2max >55 mL·kg-1·min-1). Controlling for CRF, sex significantly affected bias magnitude only at first threshold, with males having higher mean bias (+2.41 bpm) than females (-1.26 bpm). DFA-α1 thresholds are practical and reliable intensity measures, however it is unclear if they accurately represent LTs/VTs from the observed limits of agreement and unexplained variance. To optimise DFA-α1 threshold estimation across different populations, bias should be corrected based on sex and CRF.

Cognitive Behavioral Therapy for Paroxysmal Atrial Fibrillation: Heart Rate Variability, Physical Activity, and Sleep

BackgroundCognitive behavioral therapy for symptom preoccupation in paroxysmal atrial fibrillation (AF-CBT) significantly improved AF-specific quality of life in a recent trial. To what extent this may this may be associated with changes in physiological parameters is yet to be determined. ObjectivesThe purpose of this study was to assess the effects of AF-CBT on heart rate variability (HRV), physical activity, and sleep. MethodsPatients with symptomatic paroxysmal AF on optimal medical therapy (mean ± standard deviation 65.4 ± 8.3 years, 58% females, 61% on beta-blockers) were randomized to a 10-week online AF-CBT (n = 65) or AF education (n = 62). AF-CBT was therapist-led and focused on social and physical avoidance. A 5-day Patch-Holter with an integrated accelerometer was applied at baseline, post-treatment, and at 3-month follow-up to assess AF burden, HRV, physical activity, and sleep duration. Subjective assessments were made by the International Physical Activity (IPAQ) and Insomnia Severity Index questionnaires. ResultsAt baseline, participants walked on average 8040 ± 2600 steps/day and slept 8.0 ± 1.1 hours. Objective and subjective physical activity and sleep duration remained unchanged after treatment, with no significant difference between the groups. The Insomnia Severity Index score went from subclinical insomnia (12.2 ± 6.7) to near normal values (8.1 ± 5.6), a significant change compared to controls (P = 0.032). No changes were found in AF burden or HRV indices at rest during the day or at night. ConclusionsIn this select cohort, AF-CBT decreased insomnia severity but had no impact on HRV or physical activity. Thus, AF-CBT may operate through psychological and behavioral factors that are not targeted by current medical and lifestyle interventions.

Heart rate variability as a biomarker for transdiagnostic depressive and anxiety symptom trajectory in adolescents and young adults.

Internalizing psychopathology is associated with abnormalities in heart rate variability (HRV). Lower HRV that reflects reduced parasympathetic nervous system activity has been observed in depressive and anxiety disorders. Existing studies predominantly used categorical rather than dimensional approaches, the latter of which better addresses clinical comorbidity and heterogeneity. Moreover, there is little evidence on the role of HRV in longitudinal symptom trajectory in adolescents and young adults. The current study examined the association between HRV and internalizing symptom trajectory using a dimensional approach-the tri-level model of depression and anxiety. Adolescents and young adults (N = 362) were recruited in a 3-year longitudinal study, where they completed electrocardiogram recordings and self-report symptom questionnaires. Multilevel modeling was conducted with high-frequency power bands (HF power) of interbeat intervals at baseline as the predictor, and tri-level symptom factors over 3 years as the outcome. HF power significantly predicted the trajectory of the broad General Distress symptom factor, but not the intermediate Fears or Anhedonia-Apprehension symptom factors. Higher HF power was associated with a decline in General Distress over time. This association was held when neuroticism, other tri-level symptom factors, and demographic variables were covaried. That is, greater parasympathetic nervous system activity at baseline was significantly associated with a greater decline in the broad internalizing symptom factor, but not symptom factors that are more specific to depressive or anxiety disorders. Parasympathetic activity, therefore, may be a transdiagnostic biomarker for internalizing symptoms in adolescents and young adults. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Cardiovascular responses to experimental weight gain in humans: a feasibility study.

Obesity and hypertension share a well known association. However, the mechanisms underlying their relationship are not well understood. Our goal was to assess the feasibility of a longitudinal, interventional weight gain study with detailed cardiovascular measurements in humans. Sixteen healthy, normotensive, young, male volunteers (28 ± 7 years) were enrolled. Body composition, biochemical and cardiovascular data were obtained at baseline, and after an 8-week period of overfeeding (800-1000 kcal/day). Blood pressure (BP), cardiac output (CO) and peripheral vascular resistance (PVR) were determined, as were the minimum forearm vascular resistance (MFVR), forearm blood flow (FBF) response to mental stress and heart rate variability (HRV) parameters. Overfeeding resulted in a median weight gain of 5.6 kg [interquartile range (IQR) 4.6-6.4 kg; P < 0.001]. Seated systolic and diastolic BP were significantly increased by 10 ± 9 and 4 ± 6 mmHg, respectively, after weight gain ( P < 0.001 and P = 0.011, respectively). CO also increased and PVR decreased significantly as a result of weight gain ( P = 0.032 and P = 0.044, respectively). MFVR was also significantly decreased after weight gain ( P = 0.023). The FBF response to mental stress was blunted significantly ( P = 0.002), and sympathovagal balance and responsiveness to orthostatic challenge altered moderately after weight gain. Our overfeeding regimen resulted in moderate weight gain and significant increases in BP. An increase in CO is likely to be the dominant mechanism underlying the observed BP changes, with decreases in PVR partially compensating for these effects. Experimental weight gain, coupled with detailed cardiovascular phenotyping, is a feasible model to examine potential mechanisms underlying obesity-associated hypertension in young adults.

Exploring the impact of occupational exposure: A study on cardiovascular autonomic functions of male gas station attendants in Sri Lanka.

Fuel dispensing at fuel stations is performed manually by unprotected male gas station attendants in Sri Lanka, who have long working hours. These workers are exposed to hydrocarbon fuels associated with multiple health effects by modulation of the autonomic nervous system. This study was performed to determine cardiovascular autonomic functions among fuel pump attendants in Sri Lanka. Fuel pump attendants (n = 50) aged between 19 and 65 years were identified for the study from seven fuel stations. They were compared with age- and gender-matched controls (n = 46) without occupational exposure to fuel. A physical examination was performed before the autonomic function and heart rate variability (HRV) assessment. There were no significant differences in weight, height, or BMI between the study and the control populations (p > 0.05). Both the systolic blood pressure (SBP) (Mann Whitney U (MWU) = 743.5, p = 0.003) and diastolic blood pressure (DBP) (MWU = 686.5, p = 0.001) were significantly higher among the gas station attendants compared to controls. Valsalva ratio was significantly higher among the study group (MW U = 874.00, p = 0.043) compared to controls. The HRV analysis showed significantly higher SDNN and SD2 (MWU = 842.00, p = 0.034, and MWU = 843.50, p = 0.035 respectively) among the gas station attendants compared to controls. The changes to the cardiovascular autonomic parameters among those exposed to fuel vapor as a gas station attendant indicate an increase in sympathetic outflow to the vessels. In the occupational setting as fuel pump attendants need periodic monitoring.

The cAMP/PKA signaling pathway conditions cardiac performance in experimental animals with metabolic syndrome

Metabolic syndrome (MetS) increases the risk of coronary artery disease, but effects of this condition on the working myocardium remain to be fully elucidated. In the present study we evaluated the consequences of diet-induced metabolic disorders on cardiac function and myocyte performance using female mice fed with Western diet. Animals maintained on regular chow were used as control (Ctrl). Mice on the Western diet (WesD) had increased body weight, impaired glucose metabolism, preserved diastolic and systolic function, but increased left ventricular (LV) mass, with respect to Ctrl animals. Moreover, WesD mice had reduced heart rate variability (HRV), indicative of altered cardiac sympathovagal balance. Myocytes from WesD mice had increased volume, enhanced cell mechanics, and faster kinetics of contraction and relaxation. Moreover, levels of cAMP and protein kinase A (PKA) activity were enhanced in WesD myocytes, and interventions aimed at stabilizing cAMP/PKA abrogated functional differences between Ctrl and WesD cells. Interestingly, in vivo β-adrenergic receptor (β-AR) blockade normalized the mechanical properties of WesD myocytes and revealed defective cardiac function in WesD mice, with respect to Ctrl. Collectively, these results indicate that metabolic disorders induced by Western diet enhance the cAMP/PKA signaling pathway, a possible adaptation required to maintain cardiac function.

Mobile Heart Rate Variability Biofeedback for Work-Related Stress in Employees and the Influence of Instruction Format (Digital or Live) on Training Outcome: A Non-Randomized Controlled Trial.

Work-related stress is a major health issue in most industrialized countries. Heart rate variability biofeedback (HRV-BfB) can promote resilience and stress coping capacity. Mobile HRV-BfB could contribute to stress prevention in the workplace. Little is known about whether the type of training, with digital or live instruction, has an impact on the training outcome. This study analyzes the psychophysiological effects of four-week workplace resilience training with mobile HRV-BfB and the influence of instruction format (digital or live) on training success. This was a prospective, three-arm, non-randomized controlled trial with parallel group design. 73 employees of a bearing and seal manufacturer (58.9% male, 86.3% full-time employment, 67.1% office workers) attended resilience training with HRV-BfB, live (n = 24) or digital (n = 19) format, or served as waitlist controls (n = 30). HRV-BfB training spanned four weeks. Participants applied resilience techniques to increase HRV using visual biofeedback. Data were collected at baseline (T0), post-intervention (T1), and another four weeks later (T2). Primary outcome measure was the Burnout scale of the Copenhagen Psychosocial Questionnaire (COPSOQ) at T1. Secondary outcome measures included further COPSOQ scales, self-reported sleep quality (Pittsburgh Sleep Quality Index, PSQI), and HRV parameters. Burnout parameters decreased significantly in HRV-BfB and waitlist. The decrease (T0-T1 and T0-T2) showed higher effect sizes in HRV-BfB (Cohen's d: 0.63; 0.69) than in waitlist (d: 0.27; 0.36). Sleep quality improved in HRV-BfB with small effect sizes (no change for waitlist). SDNN (standard deviation of beat-to-beat intervals) increased in HRV-BfB between T0 and T1 (d: 0.23;). In subgroup analysis, digital reached higher effect sizes for improvement in burnout (d: 0.87; 0.92) and sleep quality (d: 0.59; 0.64) than live learning (burnout: d: 0.43; 0.51; sleep quality: d: 0.28; 0.22). HRV-analysis revealed no differences between subgroups. Four-week mobile HRV-BfB resilience training reduced stress and burnout symptoms in employees. No significant differences were found between HRV-BfB digital or live. Hence, companies should choose the approach that fits their company profile or, if possible, offer both formats to accommodate the different needs of employees. However, findings were nonhomogeneous and should be verified by further studies.Trial Registration: ClinicalTrials.gov , NCT04897165, 05/18/2021, retrospectively registered.

Abnormal Autonomic Nervous Regulation in Patients with Globus Pharyngeus.

Globus pharyngeus could be described as a benign sensation of lump or foreign object in the throat. The etiology of the globus as a solitary syndrome is still unknown, but it is proposed that stress could have an important role in symptom emergence. To evaluate the autonomic nervous regulation in patients with globus compared to healthy controls in reaction to stress. Patients included in the study were diagnosed based on ROME IV criteria for Disorders of Gut Brain Interaction. Besides globus, the patients did not suffer any other substantial medical condition. As a control group, measurement of healthy volunteers was performed. Both groups underwent the same stress protocol assessment in the same laboratory settings. The protocol consist of two types of stressors: cold pressor test and mental arithmetic test to test different types of autonomic reactivity. Baroreflex sensitivity was significantly decreased in patients compared to controls in all phases of the protocol. Low-frequency band of systolic blood pressure variability was significantly increasedduring both stress phases in patients compared to controls. High-frequency band of heart rate variability was significantly decreased in patients compared to controls during the both of the stress phases. The results of this study shows discrete abnormalities in complex autonomic reflex control which are predominantly manifested in response to stressful stimuli indicating altered neurocardiac regulation as a reaction to stress associated with globus pharynegus. This fact could have an important role in the personalized management of globus patients such as biofeedback.

Heart rate variability analysis for the prediction of pre-arousal during propofol-remifentanil general anaesthesia: A feasibility study.

Accidental awareness during general anaesthesia is a major complication. Despite the routine use of continuous electroencephalographic monitoring, accidental awareness during general anaesthesia remains relatively frequent and constitutes a significant additional cost. The prediction of patients' arousal during general anaesthesia could help preventing accidental awareness and some researchers have suggested that heart rate variability (HRV) analysis contains valuable information about the patient arousal during general anaesthesia. We conducted pilot study to investigate HRV ability to detect patient arousal. RR series and the Bispectral IndexTM (BISTM) were recorded during general anaesthesia. The pre-arousal period T0 was defined as the time at which the BISTM exceeded 60 at the end of surgery. HRV parameters were computed over several time periods before and after T0 and classified as "BISTM<60" or "BISTM≥60". A multivariate logistic regression model and a classification and regression tree algorithm were used to evaluate the HRV variables' ability to detect "BISTM≥60". All the models gave high specificity but poor sensitivity. Excluding T0 from the classification increased the sensitivity for all the models and gave AUCROC>0.7. In conclusion, we found that HRV analysis provided encouraging results to predict arousal at the end of general anaesthesia.

Systematic review of cognitive impairment in drivers through mental workload using physiological measures of heart rate variability

The intricate interplay between driver cognitive dysfunction, mental workload (MWL), and heart rate variability (HRV) provides a captivating avenue for investigation within the domain of transportation safety studies. This article provides a systematic review and examines cognitive hindrance stemming from mental workload and heart rate variability. It scrutinizes the mental workload experienced by drivers by leveraging data gleaned from prior studies that employed heart rate monitoring systems and eye tracking technology, thereby illuminating the correlation between cognitive impairment, mental workload, and physiological indicators such as heart rate and ocular movements. The investigation is grounded in the premise that the mental workload of drivers can be assessed through physiological cues, such as heart rate and eye movements. The study discovered that HRV and infrared (IR) measurements played a crucial role in evaluating fatigue and workload for skilled drivers. However, the study overlooked potential factors contributing to cognitive impairment in drivers and could benefit from incorporating alternative indicators of cognitive workload for deeper insights. Furthermore, investigated driving simulators demonstrated that an eco-safe driving Human-Machine Interface (HMI) significantly promoted safe driving behaviors without imposing excessive mental and visual workload on drivers. Recommendations were made for future studies to consider additional indicators of cognitive workload, such as subjective assessments or task performance metrics, for a more comprehensive understanding.

Dynamics of Respiratory Rate and Heart Rate Variability when Performing a Cognitive Task of Two Levels of Complexity

The study examined heart rate variability (HRV) and respiratory rate during a cognitive task (reading) at two difficulty levels. Time, frequency and nonlinear analysis of HRV was used. It has been shown that both some indicators of HRV (HR, SDNN, RMSSD, SD2, SD2/SD1) and respiratory rate change with increasing mental load, however, they do not separately demonstrate significant differences at all three stages of the study. Therefore, for the first time for cognitive studies, an integral indicator was used that links the parameters of the heart with respiration – the physiological cost of activity (PhysCost), which was previously used in work with athletes when they performed physical exercises to failure. Changes in the PhysCost showed that differences between a simple and a complex task are observed at all stages of the study. Thus, it has been established that the difference in the functional state of a person in the process of performing a continuous task of two levels of complexity is most reliably revealed when using an integrative indicator connecting the activity of the respiratory system and the circulatory system.

Cardiorespiratory and circadian clock markers in intensive care unit patients.

Biological synchronized rhythmicity is a critical physiological process. The lack of synchronized rhythms, mainly those showing a circadian basis, like sleep, the heart rate (HR) and arterial blood pressure (BP), often leads to several organic challenges, usually associated with adverse outcomes. The aim of the study was to investigate whether the intensive care unit (ICU) environment favors clock genes and cardiorespiratory changes. A total of 22 critically ill patients (16 males; 72.73%) with a mean age of 60.82 ±20.07 years and well-established cardiovascular conditions were selected from ICU. Blood samples were obtained, and total RNA was isolated and reverse-transcribed into complementary DNA (cDNA). A quantitative polymerase chain reaction (qPCR) was performed to assess the target gene expression levels. The urinary concentration levels of melatonin (MEL) were assessed. The heart rate, BP (systolic - SBP, diastolic - DBP and mean - MBP) and the oxygen saturation (SpO2) levels were assessed as continuous variables. The urinary MEL and Brain and muscle Arnt-like protein-1 (BMAL1) levels were shown to have a non-linear relationship with HR (coefficient (coef): 2.318, p = 0.032; coef: 2.722, p = 0.006, respectively) and SBP (coef: 1.000, p = 0.008; coef: 2.000, p = 0.037, respectively), with an explanatory power of up to 50.3% and 39.7% of the HR and SBP variability, respectively. Melatonin, but not BMAL1, was also shown to have a non-linear relationship with MBP (coef: 1.000, p = 0.007), with an explanatory power of up to 31.3% regarding the MBP variability. The HR and SBP oscillatory dynamics was shown to be related to changes in the genetic expression of BMAL1 and the urinary MEL concentrations. To a lower degree, MEL also impacted the variation of MBP. Our results suggest that not only are circadian functional matrices crucial for the dynamics of vital parameters in critically ill patients, but also that routinely assessed cardiovascular parameters like HR and BP may constitute important markers for the circadian timing system function. These parameters are easy to assess and have a relevant prognostic value regarding recovery outcomes, as well as the morbidity and mortality rates in ICU.

Relationship between autonomic and peripheral neuropathies and cardiovascular outcomes in diabetes

This review explores the complex relationship between diabetic neuropathy and cardiovascular disease (CVD). Neuropathy, a common complication of type 1 and type 2 diabetes, is divided into autonomic and peripheral types, each impacting cardiovascular health. Cardiovascular autonomic neuropathy, a form of autonomic neuropathy, is associated with various CVD complications, including arrhythmias, impaired nocturnal blood pressure regulation, and increased mortality. The prevalence of cardiovascular autonomic neuropathy varies depending on the type and duration of diabetes and is influenced by factors like glycemic control and metabolic stress. Peripheral polyneuropathy, which is often linked to diabetic foot disease, is also correlated with elevated CVD risk; research suggests shared pathophysiological mechanisms between peripheral neuropathy and cardiovascular conditions. Screening for neuropathies using tools like the Michigan Neuropathy Screening Instrument and heart rate variability analyses can facilitate early detection of CVD risk. Additionally, emerging technologies, like deep learning models, have demonstrated promise in detecting early cardiovascular patterns associated with autonomic neuropathy through electrocardiogram analysis. These findings underscore the value of integrating novel diagnostic approaches for early intervention. As CVD represents a leading cause of death among patients with diabetes, this article emphasizes the need for thorough assessment and proactive management of neuropathy to mitigate cardiovascular risk. The review recommends a multidisciplinary approach to diabetes care, including early screening, accurate risk stratification, and targeted therapeutic strategies to prevent or slow the progression of CVD in patients with autonomic and peripheral neuropathies. Further research is warranted to clarify the optimal intervention strategies for reducing CVD risk in these populations.

A Cross-Sectional Study on the Effect of Stress on Short-Term Heart Rate Variability and Muscle Strength Among Construction Site Workers

This cross-sectional study investigates the immediate impact of occupational stress on short-term heart rate variability (HRV) and muscle strength among 200 construction workers in Chennai. The Perceived Stress Scale (PSS) was employed to assess stress levels, while HRV was measured using a portable ECG device, focusing on time-domain (RMSSD) and frequency-domain (HF Power) parameters. Muscle strength was evaluated using a MicroFET 2 dynamometer. Pearson correlation and multivariate regression analyses were applied to determine the associations between stress, HRV, and muscle strength, adjusting for confounding factors such as age, body mass index (BMI), and work duration. Results revealed a significant negative correlation between perceived stress and both HRV indices (RMSSD: r=-0.45, p&lt;0.01; HF Power: r=-0.50, p&lt;0.01) as well as muscle strength (r=-0.40, p&lt;0.01). Higher stress levels were associated with reduced HRV and diminished muscle strength. Regression analyses confirmed that stress independently predicted lower HRV (RMSSD: ?=-0.35, p&lt;0.01; HF Power: ?=-0.42, p&lt;0.01) and decreased muscle strength (?=-0.32, p&lt;0.01). These findings suggest that elevated stress negatively impacts both cardiovascular and muscular functioning, potentially increasing the health risks among construction workers. The study highlights the importance of implementing stress management interventions to improve both the physical well-being and productivity of workers in the construction industry.

Physiological Predictors of Operator Performance: The Role of Mental Effort and Its Link to Task Performance.

The present study investigated how pupil size and heart rate variability (HRV) can contribute to the prediction of operator performance. We illustrate how focusing on mental effort as the conceptual link between physiological measures and task performance can align relevant empirical findings across research domains. Physiological measures are often treated as indicators of operators' mental state. Thereby, they could enable a continuous and unobtrusive assessment of operators' current ability to perform the task. Fifty participants performed a process monitoring task consisting of ten 9-minute task blocks. Blocks alternated between low and high task demands, and the last two blocks introduced a task reward manipulation. We measured response times as primary performance indicator, pupil size and HRV as physiological measures, and mental fatigue, task engagement, and perceived effort as subjective ratings. Both increased pupil size and increased HRV significantly predicted better task performance. However, the underlying associations between physiological measures and performance were influenced by task demands and time on task. Pupil size, but not HRV, results were consistent with subjective ratings. The empirical findings suggest that, by capturing variance in operators' mental effort, physiological measures, specifically pupil size, can contribute to the prediction of task performance. Their predictive value is limited by confounding effects that alter the amount of effort required to achieve a given level of performance. The outlined conceptual approach and empirical results can guide study designs and performance prediction models that examine physiological measures as the basis for dynamic operator assistance.

A Review of Factors Affecting Radiation Dose and Image Quality in Coronary CTA Performed with Wide-Detector CT

Compared with traditional invasive coronary angiography (ICA), coronary CT angiography (CCTA) has the advantages of being rapid, economical, and minimally invasive. The wide-detector CT, with its superior temporal resolution and robust three-dimensional reconstruction technology, thus enables CCTA in patients with high heart rates and arrhythmias, leading to a high potential for clinical application. This paper systematically summarizes wide-detector CT hardware configurations of various vendors routinely used for CCTA examinations and reviews the effects of patient heart rate and heart rate variability, scanning modality, reconstruction algorithms, tube voltage, and scanning field of view on image quality and radiation dose. In addition, novel technologies in the field of CT applied to CCTA examinations are also presented. Since this examination has a diagnostic accuracy that is highly consistent with ICA, it can be further used as a routine examination tool for coronary artery disease in clinical practice.

Chronic rose oxide and exercise synergistically modulate cardiovascular and autonomic functions in hypertensive rats.

With the alarming rise in cases of arterial hypertension worldwide, there is an urgent need to develop combined therapies to mitigate this scenario. Rose oxide (RO), a monoterpene with anti-inflammatory and hypotensive properties, emerges as an alternative. The present study is the first to evaluate the effect of RO administered chronically and combined with physical exercise (swimming) since both have been reported to have beneficial impacts on hypertension. Male SHR and Wistar rats (aged 12weeks) received RO for 34 consecutive days (orally; 100mg/kg). The progression of systolic arterial pressure (SAP) was monitored through tail-cuff plethysmography. Twenty-four hours before the end of the treatment, the animals were anesthetized, and the femoral artery and vein were cannulated to record the pulsatile arterial pressure and to administer drugs, respectively. Hemodynamic and autonomic parameters and baroreflex sensitivity and intrinsic heart rate (IHR) were evaluated. Treatment with RO, administered alone or combined with exercise, reduced SAP and mean arterial pressure in SHR. The swimming protocol did not prevent increases in BP, but when combined with RO, it improved autonomic control, assessed through heart rate variability and parasympathetic tone. IHR was attenuated in SHR, and none of the treatments reversed this response. Therefore, combining RO with physical exercise may enhance their antihypertensive effects, improving autonomic function, reducing oxidative stress and inflammation, providing synergistic cardiovascular benefits, improving metabolic health, promoting a comprehensive lifestyle intervention, and potentially allowing for reduced medication dosages. This multifaceted approach could offer a more effective and sustainable strategy for managing hypertension.