Validation of the Polar V800 heart rate monitor and comparison of artifact correction methods among adults with hypertension

Open access EEG dataset of repeated measurements from a single subject for microstate analysis

Electroencephalography (EEG) microstate analysis is a neuroimaging analytical method that has received considerable attention in recent years and is widely used for analysing EEG signals. EEG is easily influenced by internal and external factors, which can affect the repeatability and stability of EEG microstate analysis. However, there have been few reports and publicly available datasets on the repeatability of EEG microstate analysis. In the current study, a 39-year-old healthy male underwent a total of 60 simultaneous electroencephalography and electrocardiogram measurements over a period of three months. After the EEG recording was completed, magnetic resonance imaging (MRI) was also conducted. To date, this EEG dataset has the highest number of repeated measurements for one individual. The dataset can be used to assess the stability and repeatability of EEG microstates and other analytical methods, to decode resting EEG states among subjects with open eyes, and to explore the stability and repeatability of cortical spatiotemporal dynamics through source analysis with individual MRI.

Heart rate dynamics and asymmetry during sympathetic activity stimulation and post-stimulation recovery in ski mountaineers-a pilot exploratory study

There is a lack of studies on non-linear heart rate (HR) variability in athletes. We aimed to assess the usefulness of short-term HR dynamics and asymmetry parameters to evaluate the neural modulation of cardiac activity based on non-stationary RR interval series by studying their changes during sympathetic nervous system activity stimulation (isometric handgrip test) and post-stimulation recovery in professional ski mountaineers. The correlation between the changes in the parameters and the respiratory rate (RespRate) and also the duration of the career was analyzed. Short-term (5 min) and ultra-short-term (1 min) rates of patterns with no variations (0V), number of acceleration runs of length 1 (AR1), and short-term Porta's Index were greater, whereas Guzik's Index (GI) was smaller during sympathetic stimulation compared to rest. GI increased and the number of AR1 decreased during recovery. Greater increases in GI and RMSSD were associated with greater decreases in RespRate during recovery. Greater increases in RespRate from rest to short-term sympathetic stimulation were associated with greater increases in 0V (Max-min method) and AR1 but also with greater decreases in decelerations of short-term variance and accelerations and decelerations of long-term variance. Greater increases in 0V (Max-min method) and number of AR1 during sympathetic stimulation were associated with a shorter career duration. Greater decreases in these parameters during recovery were associated with a longer career duration. Changes in measures of HR dynamics and asymmetry, calculated based on short-term non-stationary RRi time series induced by sympathetic stimulation and post-stimulation recovery, reflected sympathovagal shift and were associated with condition-related alterations in RespRate and career duration in athletes who practice ski mountaineering.

Reliability of the Heart Rate Variability Registered Through Polar Cardio Frequency Meter in Individuals With Chronic Low Back Pain

Objective

The purpose of this study was to analyze the intra- and inter-examiner reliability of the analysis of heart rate variability (HRV) captured by a Polar cardio frequency meter in individuals with chronic nonspecific low back pain.

Methods

The study included 35 individuals with nonspecific low back pain, both sexes, aged 18 to 45. We used a Polar V800 cardio frequency meter to capture HRV in individuals in different positions, and we calculated the reliability through the intraclass correlation coefficient (ICC).

Results

Regarding intra-examiner reliability, we found excellent reliability of HRV analysis in the supine position (ICC ranging from 0.89 to 1.00) and in the standing position (ICC ranging from 0.95 to 0.99). In addition, for inter-examiner reliability, we found substantial to excellent reliability of the HRV analysis in the supine position (ICC ranging from 0.76 to 0.98) and moderate to excellent reliability in the standing position (ICC ranging from 0.73 to 0.99).

Conclusion

The HRV analysis captured by a Polar cardio frequency meter presented adequate reliability when considering different times and different examiners.

Heart rate variability behavior in athletes after a sports concussion: A systematic review

OBJECTIVE

This systematic review aims to investigate the adaptations of the autonomic nervous system (ANS) after a concussion by measuring HRV in athletes over the age of 16 after injury.

METHODS

This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). Web of Science, Pubmed, SCOPUS, and Sport Discus were searched using predefined search terms to identify relevant original cross-sectional, longitudinal, and cohort epidemiological studies published before December 2021.

RESULTS

After screening 1737 potential articles, four studies met the inclusion criteria. Studies included participants with concussion (n = 63) and healthy control athletes (n = 140) who practised different sports. Two studies describe a decrease in HRV following a sports concussion, and one proposed that the resolution of symptoms does not necessarily reflect ANS recovery. Lastly, one study concluded that submaximal exercise induces alteration in ANS, not seen in rest after an injury.

CONCLUSIONS

In the frequency domain, a decrease in high frequency power and an increase of low frequency/high frequency ratio is expected, as the activity of the sympathetic nervous system increases, and the parasympathetic nervous system decreases after injury. In the frequency domain, heart rate variability (HRV) may help monitor the activity of ANS evaluating signals of somatic tissue distress and early identification of other types of musculoskeletal injuries. Further research should investigate the relationship between HRV and other musculoskeletal injuries.

The Relationship between Postexercise Hypotension and Heart Rate Variability before and after Exercise Training

Because data are scarce, we examined the relationship between postexercise hypotension (PEH) and heart rate variability (HRV) before and after aerobic exercise training among adults with hypertension. Participants completed a 12 w aerobic training program. Before and after training, they performed a peak graded exercise stress test (GEST) and nonexercise control (CONTROL) and were left attached to an ambulatory BP monitor. Prior to CONTROL, HRV was measured supine for 5 min using a 12-lead electrocardiogram (ECG). The participants (n = 18) were middle-aged (52.1 ± 11.7 y) and 50% men with hypertension (131.7 ± 9.8/85.9 ± 8.5 mmHg) and obesity (30.0 ± 3.7 kg·m^-2). Before training, ambulatory systolic BP (ASBP) and diastolic ABP (ADBP) decreased by 3.2 ± 2.1 mmHg and 2.5 ± 1.5 mmHg, respectively, from baseline after the GEST versus CONTROL (p < 0.05). After training, ASBP tended to decrease by 3.5 ± 2.2 mmHg (p = 0.055) and ADBP decreased by 1.7 ± 2.5 mmHg (p = 0.001) from baseline after the GEST versus CONTROL. Before training, HRV high frequency (HFms²) (β = -0.441), age (β = 0.568), and resting SBP (β = 0.504) accounted for 66.8% of the ASBP response (p = 0.001), whereas the low frequency (LF)/HF ratio (β = 0.516) and resting DBP (β = 0.277) accounted for 35.7% of the ADBP response (p = 0.037). After training, the standard deviation of NN intervals (SDNN) (β = -0.556), age (β = 0.506), and resting SBP (β = 0.259) accounted for 60.7% of the ASBP response (p = 0.004), whereas SDNN (β = -0.236) and resting DBP (β = 0.785) accounted for 58.5% of the ADBP response (p = 0.001). Our preliminary findings show that adults with hypertension and parasympathetic suppression (i.e., lower SDNN and HFms² and higher LF/HF) may elicit PEH to the greatest degree independent of training status versus adults with parasympathetic predominance, suggesting that resting HRV may be an important determinant of PEH.

Laterality of blood perfusion in the lower extremities after drinking saline at different temperatures

Skin blood flux (SkBF) changes caused by drinking cold water are generally associated with vagal tone and osmotic factors in the digestive system. However, there is still a lack of relevant research on whether there are left and right differences in these SkBF change. In the current study, a total of 60 subjects were recruited. Skin blood perfusion of the bilateral lower extremities was recorded simultaneously before and after drinking saline of different temperatures saline by using Laser Doppler flowmetry (LDF). The electrogastrogram (EGG) was also monitored, and the dominant frequency of the EGG and heart rate variability were analyzed. The results indicated that after drinking saline, the laterality index of SkBF at the lower extremities was different and the laterality index changes of SkBF were mainly reflected in the frequency interval V (0.4-1.6 Hz). There was a weak negative correlation between the laterality index of endothelial NO-dependent component and change rate of root mean square of successive differences (RMSSD) after drinking 4 °C saline. However, after drinking 30 °C saline, there was a weak positive correlation between neurogenic component and RMSSD The distribution and regulation of bilateral blood flow are not symmetrical but exhibit a certain laterality.

PTSD symptom clusters and cardiovascular responses to stress: Reactivity and recovery

OBJECTIVE

Posttraumatic stress disorder (PTSD) symptoms are associated with high blood pressure (BP) and decreased heart rate variability (HRV) at rest and in response to acute stress. Unique contributions of PTSD symptom clusters to cardiovascular responses to stress are rarely investigated. This study tested whether PTSD-related arousal/reactivity drives relationships of higher PTSD symptoms with higher BP and lower HRV during rest, reactivity (stressor-induced change from baseline), and recovery.

METHODS

Using a cross-sectional observational design, we enrolled 84 trauma-exposed community adults (83% female; 68% White; Mage = 35) who endorsed at least one core PTSD symptom. Participants completed a physical exam, self-reports of trauma history and PTSD symptoms, and BP and HRV frequency domain measurements during rest, stressor (mental arithmetic task), and recovery.

RESULTS

Arousal/reactivity was not associated with BP or HRV reactivity but associated with a higher low (LF) to high (HF) frequency (HF) ratio (LF/HF) during recovery reflecting sympathetic predominance. During the stressor, more avoidance and intrusion were associated with increased diastolic blood pressure (DBP) from baseline; more avoidance was associated with parasympathetic predominance (lower LF/HF); and more negative cognitions/mood was associated with decreased systolic blood pressure (SBP), DBP, and LF from baseline. During recovery, more intrusion and negative cognitions/mood were associated with increased SBP from baseline; less negative cognitions/mood was associated with sympathetic predominance (higher LF/HF).

CONCLUSIONS

PTSD symptom clusters demonstrated differential relationships with SBP, DBP, and HRV during reactivity and recovery. Findings may inform targeted PTSD symptom reduction interventions for disrupting links between PTSD and CVD risk.

A Reasonable Officer: Examining the Relationships Among Stress, Training, and Performance in a Highly Realistic Lethal Force Scenario

Under conditions of physiological stress, officers are sometimes required to make split-second life-or-death decisions, where deficits in performance can have tragic outcomes, including serious injury or death and strained police-community relations. The current study assessed the performance of 122 active-duty police officers during a realistic lethal force scenario to examine whether performance was affected by the officer's level of operational skills training, years of police service, and stress reactivity. Results demonstrated that the scenario produced elevated heart rates (i.e., 150 beats per minute), as well as perceptual and cognitive distortions, such as tunnel vision, commensurate with those observed in naturalistic use of force encounters. The average performance rating from the scenario was 59%, with 27% of participants making at least one lethal force error. Elevated stress reactivity was a predictor of poorer performance and increased lethal force errors. Level of training and years of police service had differential and complex effects on both performance and lethal force errors. Our results illustrate the need to critically reflect on police training practices and continue to make evidence-based improvements to training. The findings also highlight that while training may significantly improve outcomes, flawless performance is likely not probable, given the limits of human performance under stress. Implications for the objective reasonableness standard, which is used to assess the appropriateness of force in courts of law, are discussed.

Non-Invasive Physiological Monitoring for Physical Exertion and Fatigue Assessment in Military Personnel: A Systematic Review

During operational activities, military personnel face extremely demanding circumstances, which when combined lead to severe fatigue, influencing both their well-being and performance. Physical exertion is the main condition leading to fatigue, and its continuous tracking would help prevent its effects. This review aimed to investigate the up-to-date progress on non-invasive physiological monitoring to evaluate situations of physical exertion as a pre-condition to fatigue in military populations, and determine the potential associations between physiological responses and fatigue, which can later result in decision-making indicators to prevent health-related consequences. Adhering to the PRISMA Statement, four databases (Scopus, Science Direct, Web of Science and PubMed) were used for a literature search based on combinations of keywords. The eligibility criteria focused on studies monitoring physiological variables through non-invasive objective measurements, with these measurements being developed in military field, combat, or training conditions. The review process led to the inclusion of 20 studies. The findings established the importance of multivariable assessments in a real-life context to accurately characterise the effects of military practices. A tendency for examining heart rate variables, thermal responses, and actigraphy measurements was also identified. The objectives and experimental protocols were diverse, but the effectiveness of non-invasive measurements in identifying the most fatigue-inducing periods was demonstrated. Nevertheless, no assessment system for standardised application was presented. Future work may include the development of assessment methods to translate physiological recordings into actionable information in real-time and mitigate the effects of fatigue on soldiers’ performance accurately.

Relationship of Cardiac Autonomic Modulation with Cardiovascular Parameters in Adults, According to Body Mass Index and Physical Activity

This study aimed to analyze the relationship between cardiac autonomic modulation (CAM) and cardiovascular parameters (blood pressure and resting heart rate) in a sample of 256 adults, grouped by body mass index and sufficient moderate-to-vigorous physical activity (≥150 min/week). The sample showed different cardiovascular parameters and CAM according to body mass index, but not according to physical activity. Adults who are overweight and physically active presented higher relationship between CAM and blood pressure than those who are insufficiently active, similarly to normal weight groups. Recommended levels of physical activity may play an important role in the relationship of HRV with cardiovascular parameters in overweight adults, regardless of sex, age, socioeconomic level, and central fat. Trial registration: Registered at ClinicalTrials.gov (NCT03986879). Graphical abstract.

Sensors for Continuous Monitoring of Surgeon's Cognitive Workload in the Cardiac Operating Room

Monitoring healthcare providers’ cognitive workload during surgical procedures can provide insight into the dynamic changes of mental states that may affect patient clinical outcomes. The role of cognitive factors influencing both technical and non-technical skill are increasingly being recognized, especially as the opportunities to unobtrusively collect accurate and sensitive data are improving. Applying sensors to capture these data in a complex real-world setting such as the cardiac surgery operating room, however, is accompanied by myriad social, physical, and procedural constraints. The goal of this study was to investigate the feasibility of overcoming logistical barriers in order to effectively collect multi-modal psychophysiological inputs via heart rate (HR) and near-infrared spectroscopy (NIRS) acquisition in the real-world setting of the operating room. The surgeon was outfitted with HR and NIRS sensors during aortic valve surgery, and validation analysis was performed to detect the influence of intra-operative events on cardiovascular and prefrontal cortex changes. Signals collected were significantly correlated and noted intra-operative events and subjective self-reports coincided with observable correlations among cardiovascular and cerebral activity across surgical phases. The primary novelty and contribution of this work is in demonstrating the feasibility of collecting continuous sensor data from a surgical team member in a real-world setting.