Nocturnal Heart Research Articles

Individualized Endurance Training Based on Recovery and Training Status in Recreational Runners.

ABSTRACTPurposeLong-term development of endurance performance requires a proper balance between strain and recovery. Because responses and adaptations to training are highly individual, this study examined whether individually adjusted endurance training based on recovery and training status would lead to greater adaptations compared with a predefined program.MethodsRecreational runners were divided into predefined (PD; n = 14) or individualized (IND; n = 16) training groups. In IND, the training load was decreased, maintained, or increased twice a week based on nocturnal heart rate variability, perceived recovery, and heart rate–running speed index. Both groups performed 3-wk preparatory, 6-wk volume, and 6-wk interval periods. Incremental treadmill tests and 10-km running tests were performed before the preparatory period (T0) and after the preparatory (T1), volume (T2), and interval (T3) periods. The magnitude of training adaptations was defined based on the coefficient of variation between T0 and T1 tests (high >2×, low <0.5×).ResultsBoth groups improved (P < 0.01) their maximal treadmill speed and 10-km time from T1 to T3. The change in the 10-km time was greater in IND compared with PD (−6.2% ± 2.8% vs −2.9% ± 2.4%, P = 0.002). In addition, IND had more high responders (50% vs 29%) and fewer low responders (0% vs 21%) compared with PD in the change of maximal treadmill speed and 10-km performance (81% vs 23% and 13% vs 23%), respectively.ConclusionsPD and IND induced positive training adaptations, but the individualized training seemed more beneficial in endurance performance. Moreover, IND increased the likelihood of high response and decreased the occurrence of low response to endurance training.

The importance of beta-blocker treatment in diabetic hypertensive patients with different dipper patterns, in special on the nocturnal non-dipper profile

Background and Aims : This study aims the effectiveness of beta-blocker treatment on nocturnal heart rate and high blood pressure ( HBP) levels, especially in the non-dippers pattern, comparing mean heart rate (MHR) and mean arterial pressure (MAP).

Reliability and Sensitivity of Nocturnal Heart Rate and Heart-Rate Variability in Monitoring Individual Responses to Training Load.

To assess the reliability of nocturnal heart rate (HR) and HR variability (HRV) and to analyze the sensitivity of these markers to maximal endurance exercise. Recreational runners recorded nocturnal HR and HRV on nights after 2 identical low-intensity training sessions (n = 15) and on nights before and after a 3000-m running test (n = 23). Average HR, the natural logarithm of the root mean square of successive differences (LnRMSSD), and the natural logarithm of the high-frequency power (LnHF) were analyzed from a full night (FULL), a 4-hour (4H) segment starting 30minutes after going to sleep, and morning value (MOR) based on the endpoint of the linear fit through all 5-minute averages during the night. Differences between the nights were analyzed with a general linear model, and intraclass correlation coefficient (ICC) was used for internight reliability assessments. All indices were similar between the nights followed by low-intensity training sessions. A very high ICC (P < .001) was observed in all analysis segments with a range of .97 to .98 for HR, .92 to .97 for LnRMSSD, and .91 to .96 for LnHF. HR increased (P < .001), whereas LnRMSSD (P < .01) and LnHF (P < .05) decreased after the 3000-m test compared with previous night only in 4H and FULL. Increments in HR (P < .01) and decrements in LnRMSSD (P < .05) were greater in 4H compared with FULL and MOR. Nocturnal HR and HRV indices are highly reliable. Demanding maximal exercise increases HR and decreases HRV most systematically in 4H and FULL segments.

Nighttime hemodynamic phenotype. A novel risk factor for cardiovascular disease, especially heart failure: the practitioner-based nationwide JAMP study.

Non-dipper and riser patterns of nocturnal blood pressure (BP) are risk factors for cardiovascular disease (CVD), including heart failure (HF). However, the risk associated with a disrupted nocturnal pattern of heart rate is not well known. To investigate whether the nighttime heart rate is a risk factor for HF, alongside nighttime BP phenotype. The practitioner-based, nationwide, prospective Japan Ambulatory Blood Pressure Monitoring Prospective (JAMP) study included patients with ≥ 1 CVD risk factor but without symptomatic CVD at baseline. All patients underwent 24-h ambulatory BP monitoring at baseline and were followed annually. Nocturnal heart rate dipping (%) was calculated as 100•[1 - nighttime/daytime heart rate]. During a mean 4.5years' follow-up in 6,359 patients (mean age 68.6years), there were 306 CVD events (119 stroke, 99 coronary artery disease, and 88 HF). A 10-beats/min increase in nighttime heart rate was significantly associated with a 36-47% increase in the risk of total CVD, stroke and HF events independently of office SBP and nighttime SBP (all p < 0.005). The CVD and HF risk associated with nocturnal heart rate dipping status was independent of office and 24-h systolic BP and nocturnal BP dipping status (p < 0.001). Performance of the final model for predicting HF including BP parameters was significantly improved by the addition of nocturnal heart rate dipping patterns (p = 0.038; C-statistic 0.852). Nighttime non-dipper and riser patterns of heart rate were associated with CVD especially HF, independently and additively of nocturnal BP dipping status, indicating the importance of antihypertensive strategies targeting nighttime hemodynamics. URL: https://www.umin.ac.jp/ctr/ ; Unique identifier: UMIN000020377.

Effect of transcutaneous auricular vagus nerve stimulation on nocturnal autonomic nervous function in primary insomnia patients

To observe the effect of transcutaneous auricular vagus nerve stimulation (taVNS) on the sleep quality and nocturnal heart rate variability (HRV) in patients with primary insomnia. Twenty-one patients with primary insomnia were included. Using SDZ-ⅡB electric acupuncture apparatus, Xin (CO15) and Shen (CO10) were stimulated with disperse-dense wave, 4 Hz/ 20 Hz in frequency, (0.2±30%) ms of pulse width and tolerable intensity. Electric stimulation was given once every morning and evening of a day, 30 min each time, for 4 weeks totally. Before and after treatment, the score of Pittsburgh sleep quality index (PSQI), objective sleep structure (total sleep time [TST], sleep latency [SL], wake after sleep onset [WASO], sleep efficiency [SE], the percentages of non-rapid eye movement period 1, 2, 3, and the percentage of rapid eye movement period to TST [N1%, N2%, N3%, REM%] ) and nocturnal HRV (high frequency [HF], low frequency [LF], the ratio of LF to HF [LF/HF], standard deviation for the normal RR intervals [SDNN], squared root of the mean sum of squares of differences between adjacent intervals RR [RMSSD], the percentage of adjacent RR intervals with differences larger than 50 ms in the entire recording [PNN50%], the mean of sinus RR intervals [NNMean] ) were compared in the patients separately. After treatment, the score of each item and the total score of PSQI and SL were all reduced as compared with those before treatment (P<0.01, P<0.001); SE, N3%, LF, HF, LF/HF, SDNN, NNMean and RMSSD were all increased compared with those before treatment (P<0.001, P<0.01). The taVNS improves the sleep quality and objective sleep structure in patients with primary insomnia, which is probably related to the regulation of autonomic nervous functions.

Twenty-four-hour blood pressure and heart rate variability are reduced in patients on left ventricular assist device support.

Limited data exist on the circadian blood pressure (BP) and heart rate (HR) variations that occur in heart failure (HF) patients on left ventricular assist device (LVAD) support. We prospectively recorded clinic and 24-hour ambulatory BP and HR data in patients on HeartMate II LVAD support. Results were compared to HF patients with ejection fraction ≤30% and controls with no history of cardiovascular disease. Physiologic nocturnal BP and HR dipping was defined as a ≥10% decline compared to daytime values. Twenty-nine LVAD patients (age 59 ± 15 years, 76% male, 38% ischemic etiology), 25 HF patients (age 64 ± 13 years, 84% male, 32% ischemic etiology) and 26 controls (age 56 ± 9 years, 62% male) were studied. Normal nocturnal BP dipping was less frequent in LVAD patients (10%) than in HF patients (28%) and controls (62%) and reversed BP dipping (BP increase at night) was more common in LVAD patients (24%), compared to HF (16%) and controls (8%), (p < 0.001, for all comparisons). Physiologic HR reduction was less frequent in LVAD patients (14%), compared to HF (16%) and controls (59%) (p < 0.001, for all comparisons). Among LVAD patients, 36% exhibited sustained hypertension over the 24-hours and 25% had white-coat hypertension. Treatment of advanced HF with an LVAD does not restore physiologic circadian variability of BP and HR; additionally, BP was not adequately controlled in more than a third of LVAD patients, and a quarter of them exhibited white-coat hypertension. Future studies are warranted to confirm these findings and investigate prognostic and management implications in this population.

0103 Feasibility of examining component-specific effects of yogic breathing on heart rate variability during sleep: A three-arm pilot RCT

Abstract Introduction Wearable devices and mind-body interventions (MBIs) continue to receive widespread interest as tools for improving sleep. This study investigated the feasibility of using an automated electronic survey system and wearable heart rate (HR) monitor in the context of a fully remote clinical trial study to produce detailed measures of participant adherence, daily sleep quality, and associations with physiological outcomes captured by wearable devices. Methods Eighteen healthy participants (age 18-30yrs, 12 female) were randomized to one of three 8-week long interventions: slow-paced breathing (SPB, N=5, 24.6 ± 2.1 years, 4 female), mindfulness (M, N=6, 23.7 ± 3.7 years, 4 female), or yogic breathing (SPB+M, N=7, 24.3 ± 3.1 years). Participants completed two weeks of daily sleep logs prior to a virtual laboratory visit, consisting of a 60-min intervention-specific training with 20-min guided practice, and subsequent tasks including experimental stress induction. Participants started a 24-hour HR recording using a Polar H10 chest strap on the night prior. Then, participants were instructed to repeat their assigned intervention practice daily, using a guided audio similar to their initial training, while concurrently recording HR data and completing a detailed practice log. HR interbeat interval data were examined with spectral analysis using full spectrograms for inspection of timecourse and frequency-specific patterns in both the nocturnal recordings and daily practice sessions. Results Participants completed an average of 75% of daily practice sessions across the 8-week intervention period (SPB: 77%, M: 65%, SPB+M: 77%). An automated procedure was developed to analyze and visualize the timecourse of HRV-derived breathing patterns in the 754 completed practice sessions and 36 nocturnal recordings. The three groups were then successfully distinguishable based on breathing rates and mindfulness questionnaires. Nocturnal HR recordings demonstrated visually identifiable patterns of interindividual variability and intraindividual consistency. Statistical analysis is ongoing to further characterize these patterns. Conclusion These findings support feasibility for a fully remote, semi-automated clinical trial study assessing component-specific effects of these MBIs on sleep, including detailed spectral analysis of high-quality HR data. Future studies would benefit from examining scalability of this type of study design with wearable physiology in both clinical and nonclinical populations. Support (If Any) Pilot Research Grant, Osher Center for Integrative Medicine of Harvard Medical School and Brigham &amp; Women’s Hospital; National Institutes of Health (5T32HL007901-22)

Predictors of heart failure events detected by a multisensor implantable defibrillator algorithm

Abstract Funding Acknowledgements Type of funding sources: None. Background Cardiovascular and non-cardiovascular comorbidities are common in heart failure (HF) patients and determine disease severity and prognosis. Select modern implantable defibrillators (ICDs) are equipped with multisensor algorithms for HF monitoring. The HeartLogic index combines multiple ICD-based sensor data (heart rate, heart sounds, thoracic impedance, respiration, activity), and the associated alert has proved to be a sensitive and timely predictor of impending HF decompensation in cardiac resynchronization therapy (CRT) patients. Purpose This analysis aims to investigate the performance of the algorithm in non-CRT patients, as well as in relation to the presence of comorbidities. Methods The HeartLogic feature was activated in 568 ICD patients (410 with CRT) from 26 centers. The median follow-up was 25 months [25th–75th percentile: 15-35]. Results We recorded 1200 HeartLogic alerts (0.71 alerts per patient-year) in 370 patients. Among patient characteristics, atrial fibrillation (AF) at implantation (HR: 1.62, 95%CI: 1.27-2.07, p&amp;lt;0.001) and chronic kidney disease (CKD) (HR: 1.53, 95%CI: 1.21-1.93, p&amp;lt;0.001) independently predicted alerts. HeartLogic alerts were not associated with CRT vs. non-CRT device implantation (HR: 1.03, 95%CI: 0.82-1.30, p=0.775). Comparing the combined index and all physiologic parameters during clinically stable periods we did not notice differences between CRT and non-CRT patients. Thoracic impedance was significantly lower in CKD than non-CKD patients. (46±11ohm versus 49±10ohm; p=0.047). We found a higher S3 amplitude (0.9±0.3mG versus 0.8±0.2mG; p=0.005) and nocturnal heart rate (72±9bpm versus 66±7bpm; p&amp;lt;0.001), and lower S1 amplitude (2.0±0.8mG versus 2.4±0.9mG; p&amp;lt;0.001) in AF patients vs non-AF. These differences persisted at the time of alerts (all p&amp;lt;0.05). In the overall population, and in patients stratified by device type, CKD and AF, we measured significant changes of all contributing sensors (paired t-test; p&amp;lt;0.05) from clinically stable periods to the time of alert. Conclusions The burden of HeartLogic alerts appears similar between CRT and non-CRT patients, while patients with AF and CKD seem more exposed to alerts. ICD-measured thoracic impedance is sensitive to the fluid overload that characterizes kidney disease, as well as the first and third heart sound amplitudes seem sensitive to the reduced ventricular efficiency during AF. Nonetheless, ICD sensors seem to equally contribute to the HeartLogic alerts in all patient subgroups.

P349 A REPRODUCIBLE SENSOR PATTERN TO SUSPECT COVID19 PULMONARY INFECTION WITH LATITUDETM. CASE REPORT AND LITERATURE REVIEW

A 78 year–old patient with post–ischaemic dilated cardiomyopathy and severely reduced ejection fraction was implanted with a Boston Scientific RESONATE X4 CRT–D and followed by LATITUDETM remote monitoring platform. From the end of January to the end of March 2021 he was hospitalized for COVID19 pneumonia followed by two episodes of acute heart decompensation. We remotely followed the patient and identified a specific Heart Logic sensor pattern linked to the COVID19 pneumonia: an increase of the thoracic impedance combined with an increase of the respiratory rate (RR), S1 heart sound and the nocturnal heart rate (nHR). This pattern differed from the one linked to the subsequent episodes of heart failure, characterized by a decrease of the thoracic impedance and of S1 heart sound combined with a high RR and nHR. We eventually made a literature review on the topic and found that our observations were in line with what was published: an increase in the thoracic impedance in association with an increase in the RR and a decrease in the activity level was present in the majority of published COVID19 patients followed by LATITUDETM remote monitoring platform. Furthermore a recent comparative study found that the thoracic impedance was significantly higher in COVID–19 patients as compared with acute HF patients, suggesting an underlying pathophysiological mechanism related to pulmonary infection.The present case and the literature review show that LATITUDETM remote monitoring algorithm may become a useful tool to remotely detect SARS–CoV–2 infection, distinguish it from HF and lead to an early hospitalisation for symptomatic patients or to a simple home monitoring.

Hemodiyaliz Hastalarında Yüksek Serum Ürik Asit/HDL-Kolesterol Oranı Kardiyovasküler Risk ile İlişkilidir

Aim: Chronic kidney disease (CKD) is a progressive disease in which frequent cardiovascular (CV) comorbidities. High uric acid to HDL-cholesterol ratio (UHR) results were quite notable in patients receiving peritoneal dialysis. Thus, in this study, we aimed to evaluate the UHR results in dialysis patients.&#x0D; Materials and Methods: This retrospective, multicenter, cross-sectional study was conducted with CKD patients, and the control group consisted of hypertensive patients with a normal glomerular filtration rate (GFR). Patients’ laboratory, ambulatory blood pressure monitoring, and demographic records were obtained from the follow-up cases of two university hospitals’ internal medicine and nephrology departments. The patients' group then were divided into five subsets according to GFR. &#x0D; Results: A total of 124 CKD patients and 127 control participated in this study. All CKD patients were also identified as pre-dialysis and dialysis. The cases of UHR, non-dipper blood pressure pattern, and nocturnal heart rate (HR) were increased in CKD compared to the control group. Per disease progression, the non-dipper HR and nocturnal HR were more significant in patients receiving dialysis with high UHR than in the pre-dialysis subset. In diabetic patients with an on-targeted HbA1c, those with high UHRs still had nocturnal diastolic BP elevations. Finally, there was not an exact stage-specific result for pulse wave velocity.&#x0D; Conclusions: Based on our results, dialysis patients with high UHRs have higher non-dipper PR, nocturnal heart rate, and nocturnal diastole blood pressure, associated with CV risk. Moreover, effective diabetic management might not prevent CV risk in dialysis patients with high UHRs.

Clinical Utility of HeartLogic, a Multiparametric Telemonitoring System, in Heart Failure.

Telemonitoring through multiple variables measured on cardiac devices has the potential to improve the follow-up of patients with heart failure. The HeartLogic algorithm (Boston Scientific), implemented in some implantable cardiac defibrillators and cardiac resynchronisation therapy, allows monitoring of the nocturnal heart rate, respiratory movements, thoracic impedance, physical activity and the intensity of heart tones, with the aim of predicting major clinical events. Although HeartLogic has demonstrated high sensitivity for the detection of heart failure decompensations, its effects on hospitalisation and mortality in randomised clinical trials has not yet been corroborated. This review details how the HeartLogic algorithm works, compiles available evidence from clinical studies, and discusses its application in daily clinical practice.

Association between nocturnal heart rate variability and incident cardiovascular disease events: The HypnoLaus population-based study.

Although heart rate variability (HRV) is widely used to assess cardiac autonomic function, few studies have specifically investigated nocturnal HRV. The purpose of this study was to assess the association between nocturnal HRV and cardiovascular disease (CVD) incidence over 4 years in a population-based sample. A total of 1784 participants (48.2% men; 58 ± 11 years) from the HypnoLaus population-based cohort free of CVD at baseline were included. Polysomnography-based electrocardiograms were exported to analyze time- and frequency-domain HRV, Poincaré plots indices, detrended fluctuation analysis, acceleration capacity (AC) and deceleration capacity (DC), entropy, heart rate fragmentation (HRF), and heart rate turbulence. Multivariable-adjusted Cox regression analysis was used to assess the association between HRV indices and incident CVD events. Sixty-seven participants (3.8%) developed CVD over mean follow-up of 4.1 ± 1.1 years. In a fully adjusted model, AC (hazard ratio per 1-SD increase; 95% confidence interval: 1.59; 1.17-2.16; P = .004), DC (0.63; 0.47-0.84; P = .002), and HRF (1.41; 1.11-1.78; P = .005) were the only HRV metrics significantly associated with incident CVD events after controlling for false discovery rate. Nocturnal novel HRV parameters such as AC, DC, and HRF are better predictors of CVD events than time and frequency traditional HRV parameters. These findings suggest a form of dysautonomia and fragmented rhythms, but further experimental studies are needed to delineate the underlying physiological mechanisms of these novel HRV parameters.

Cardiovascular outcomes in obstructive sleep apnoea and implications of clinical phenotyping on effect of CPAP treatment

BackgroundThere is a growing awareness of the heterogeneity of obstructive sleep apnoea (OSA). Clinical trials of CPAP treatment on cardiovascular protection have been mostly negative. We aimed to assess the...

Nocturnal heart rate rising is a risk factor for poor renal outcomes in patients with chronic kidney disease and hypertension.

The association of heart rate (HR) dipping pattern with renal outcomes in chronic kidney disease (CKD) patients with hypertension has never been investigated. In order to demonstrate if HR dipping pattern is a risk factor for renal outcomes, cardiovascular (CV) diseases, and mortality in hypertensive patients with CKD, we conducted the prospective longitudinal observational study. Patients were divided into three groups according to their nocturnal HR: HR dippers (night–day HR ratio ≤ 0.9), HR non‐dippers (0.9 < night–day HR ratio ≤ 1.0), and HR risers (night–day HR ratio > 1.0). The primary outcome was renal endpoint, a composite outcome of progression to end‐stage renal disease (ESRD) or estimated glomerular filtration rate (eGFR) decline ≥ 50%; the secondary outcomes included poor renal outcomes, CV events, and death. A total of 34 (11.3%) patients reached renal endpoint after a follow‐up of 34 ± 17 months. Both HR non‐dippers and HR risers were predictive to renal endpoint (hazard ratio 2.58, 95% confidence interval (CI) 1.04‐ 6.4, P = .04; hazard ratio 3.95, 95% CI 1.33‐ 11.79, P = .01, respectively), while only HR risers was shown to be correlated with a decline in eGFR≥ 50% (hazard ratio 5.28, 95% CI 1.45–19.16, P < .05), and decline in eGFR (β ‐0.17, 95% CI ‐0.33‐ ‐0.01, P = .04). No predictive value was found for HR dipping pattern to mortality and CV events. In conclusion, our study provided the first evidence that HR non‐dippers, especially risers were a risk factor for poor renal outcomes in hypertensive patients with CKD.

Physiological, Perceptual, and Performance Responses to the 2-Week Block of High- versus Low-Intensity Endurance Training.

This study examined the physiological, perceptual, and performance responses to a 2-wk block of increased training load and compared whether responses differ between high-intensity interval (HIIT) and low-intensity training (LIT). Thirty recreationally trained males and females performed a 2-wk block of 10 HIIT sessions (INT, n = 15) or 70% increased volume of LIT (VOL, n = 15). Running time in the 3000 m and basal serum and urine hormone concentrations were measured before (T1) and after the block (T2), and after a recovery week (T3). In addition, weekly averages of nocturnal heart rate variability (HRV) and perceived recovery were compared with the baseline. Both groups improved their running time in the 3000 m from T1 to T2 (INT = -1.8% ± 1.6%, P = 0.003; VOL = -1.4% ± 1.7%, P = 0.017) and from T1 to T3 (INT = -2.5% ± 1.6%, P < 0.001; VOL = -2.2% ± 1.9%, P = 0.001). Resting norepinephrine concentration increased in INT from T1 to T2 (P = 0.01) and remained elevated at T3 (P = 0.018). The change in HRV from the baseline was different between the groups during the first week (INT = -1.0% ± 2.0% vs VOL = 1.8% ± 3.2%, P = 0.008). Muscle soreness increased only in INT (P < 0.001), and the change was different compared with VOL across the block and recovery weeks (P < 0.05). HIIT and LIT blocks increased endurance performance in a short period. Although both protocols seemed to be tolerable for recreational athletes, a HIIT block may induce some negative responses such as increased muscle soreness and decreased parasympathetic activity.

Accuracy Assessment of Oura Ring Nocturnal Heart Rate and Heart Rate Variability in Comparison With Electrocardiography in Time and Frequency Domains: Comprehensive Analysis.

BackgroundPhotoplethysmography is a noninvasive and low-cost method to remotely and continuously track vital signs. The Oura Ring is a compact photoplethysmography-based smart ring, which has recently drawn attention to remote health monitoring and wellness applications. The ring is used to acquire nocturnal heart rate (HR) and HR variability (HRV) parameters ubiquitously. However, these parameters are highly susceptible to motion artifacts and environmental noise. Therefore, a validity assessment of the parameters is required in everyday settings.ObjectiveThis study aims to evaluate the accuracy of HR and time domain and frequency domain HRV parameters collected by the Oura Ring against a medical grade chest electrocardiogram monitor.MethodsWe conducted overnight home-based monitoring using an Oura Ring and a Shimmer3 electrocardiogram device. The nocturnal HR and HRV parameters of 35 healthy individuals were collected and assessed. We evaluated the parameters within 2 tests, that is, values collected from 5-minute recordings (ie, short-term HRV analysis) and the average values per night sleep. A linear regression method, the Pearson correlation coefficient, and the Bland–Altman plot were used to compare the measurements of the 2 devices.ResultsOur findings showed low mean biases of the HR and HRV parameters collected by the Oura Ring in both the 5-minute and average-per-night tests. In the 5-minute test, the error variances of the parameters were different. The parameters provided by the Oura Ring dashboard (ie, HR and root mean square of successive differences [RMSSD]) showed relatively low error variance compared with the HRV parameters extracted from the normal interbeat interval signals. The Pearson correlation coefficient tests (P<.001) indicated that HR, RMSSD, average of normal heart beat intervals (AVNN), and percentage of successive normal beat-to-beat intervals that differ by more than 50 ms (pNN50) had high positive correlations with the baseline values; SD of normal beat-to-beat intervals (SDNN) and high frequency (HF) had moderate positive correlations, and low frequency (LF) and LF:HF ratio had low positive correlations. The HR, RMSSD, AVNN, and pNN50 had narrow 95% CIs; however, SDNN, LF, HF, and LF:HF ratio had relatively wider 95% CIs. In contrast, the average-per-night test showed that the HR, RMSSD, SDNN, AVNN, pNN50, LF, and HF had high positive relationships (P<.001), and the LF:HF ratio had a moderate positive relationship (P<.001). The average-per-night test also indicated considerably lower error variances than the 5-minute test for the parameters.ConclusionsThe Oura Ring could accurately measure nocturnal HR and RMSSD in both the 5-minute and average-per-night tests. It provided acceptable nocturnal AVNN, pNN50, HF, and SDNN accuracy in the average-per-night test but not in the 5-minute test. In contrast, the LF and LF:HF ratio of the ring had high error rates in both tests.

Evaluation of nocturnal vs. morning measures of heart rate indices in young athletes.

PurposeThe purpose of this study was to compare heart rate (HR) and heart rate variability in young endurance athletes during nocturnal sleep and in the morning; and to assess whether changes in these values are associated with changes in submaximal running (SRT) and counter-movement jump (CMJ) performance.MethodsDuring a three-week period of similar training, eleven athletes (16 ± 1 years) determined daily HR and heart rate variability (RMSSD) during sleep utilizing a ballistocardiographic device (Emfit QS), as well as in the morning with a HR monitor (Polar V800). Aerobic fitness and power production were assessed employing SRT and CMJ test.ResultsComparison of the average values for week 1 and week 3 revealed no significant differences with respect to nocturnal RMSSD (6.8%, P = 0.344), morning RMSSD (13.4%, P = 0.151), morning HR (-3.9 bpm, P = 0.063), SRT HR (-0.7 bpm, P = 0.447), SRT blood lactate (4.9%, P = 0.781), CMJ (-4.2%, P = 0.122) or training volume (16%, P = 0.499). There was a strong correlation between morning and nocturnal HRs during week 1 (r = 0.800, P = 0.003) and week 3 (r = 0.815, P = 0.002), as well as between morning and nocturnal RMSSD values (for week 1, r = 0.895, P<0.001 and week 3, r = 0.878, P = 0.001).ConclusionThis study concluded that HR and RMSSD obtained during nocturnal sleep and in the morning did not differ significantly. In addition, weekly changes in training and performance were small indicating that fitness was similar throughout the 3-week period of observation. Consequently, daily measurement of HR indices during nocturnal sleep provide a potential tool for long-term monitoring of young endurance athletes.

Association of nocturnal subconjunctival hemorrhage and non-dipper blood pressure pattern: A benign clue for serious diseases.

To evaluate the association between non-dipper blood pressure pattern and subconjunctival hemorrhage (SCH). Twenty-seven consecutive patients with nocturnal SCH and 27 age, sex-matched controls were enrolled. Demographic, blood parameters, office blood pressure measurements, 24-h ambulatory blood pressure monitoring (ABPM) were evaluated. Mean diastolic blood pressure (DBP) for nighttime (65.03 ± 7.1 vs. 70.78 ± 10.5, p: 0.22), mean heart rate for nighttime (64.54 ± 8.26 vs. 69.93 ± 9.85, p: 0.034), Minimum Systolic Blood pressure(SBP) and DBP values for nighttime (92.44 ± 9.72 vs. 99.44 ± 10.66, p:0.015 and 51.15 ± 8.31 vs. 57.7 ± 11.2, p: 0.018) were higher, nocturnal fall ratio of SBP and DBP were significantly lower in the SCH ( + ) group compared to SCH (-) group (5.38 ± 8.39 vs. 10.34 ± 6.08, p: 0.016 and 4.26 ± 8.92 vs. 13.78 ± 6.97, p < 0001 respectively). Ten patients (37%) in the SCH (-) group and 18 patients (66.7%) in the SCH ( + ) group were non-dippers (p: 0.029). Mean daytime SBP and DBP were higher compared to office measurements of 4 patients (14.8%) in the SCH (-) group and 11 patients (40.7%) in the SCH ( + ) group (p: 0.033). SCH had a strong association with non-dipper blood pressure pattern, higher nocturnal heart rate and masked hypertension which are precursors of myocardial infarction, stroke and renal failure. So, SCH should be considered as a clue for serious diseases such as coronary artery disease, myocardial infarction, stroke and patients should be evaluated for ABPM.

Association of Nocturnal Heart Rate with White Matter Hyperintensity Burden in Cerebral Small Vessel Disease Patients.

Age and hypertension are widely considered to be the main risk factors for white matter hyperintensity (WMH), but they do not account for all the pathophysiological mechanisms of WMH.Therefore, identifying novel risk factors is significant to improve our understanding of the etiology and consequences of WMH. To examine the association of heart rate(HR) and common vascular risk factors with WMH burden in patients hospitalized for Cerebral Small Vessel Disease(CSVD). The study consisted of 778 patients who underwent 24-hour ambulatory blood pressure and HR monitoring and brain magnetic resonance imaging(MRI). The relationship of HR measures and vascular risk factors with the presence of log WMHV4 was analyzed.Univariable and multivariable analysis was carried out to investigate the relationship of incidence of severe WMH (4th quartile, ≥19.64 ml) and HR measures and common vascular risk factors. Multivariate analysis showed that WMHV was independently predicted by nighttime HR ( OR (95% CI): 1.041（1.02~1.062）, P<0.001),Homocysteine ( OR (95% CI): 1.019（1.005~1.033）, P=0.009), and cerebral infarction ( OR (95% CI): 0.463（0.31~0.691）, P<0.001), No similar association was observed for daytime HR、HR variability and other vascular risk factors. As nighttime HR、Hcy increased, log WMHV increased accordingly; furthermore, patients with cerebral infarction were more likely to have higher levels of WMHV. nighttime HR 、Hcy、cerebral infarction was associated with WMHV, suggesting independent roles of their in WMHV. The influence of HRV on WMHV needs to be addressed by further studies.

Decreased nocturnal heart rate variability and potentially related brain regions in arteriosclerotic cerebral small vessel disease

BackgroundTo assess heart rate variability (HRV) among patients with arteriosclerotic cerebral small vessel disease (CSVD) by comparing with control subjects, and to determine whether HRV parameters were related to structural alterations in brain regions involved in autonomic regulation among CSVD patients.MethodsWe consecutively recruited subjects aged between 50 and 80 years who visited the Stroke Prevention Clinic of our hospital and have completed brain magnetic resonance imaging examination from September 1, 2018 to August 31, 2019. Polysomnography and synchronous analyses of HRV were then performed in all participants. Multivariable binary logistic regression was used to identify the relationship between HRV parameters and CSVD. Participants were invited to further undergo three-dimensional brain volume scan, and the voxel based morphometry (VBM) analysis was used to identify gray matter atrophy.ResultsAmong 109 participants enrolled in this study, 63 were assigned to the arteriosclerotic CSVD group and 46 to the control group. Lower standard deviation of normal-to-normal intervals (SDNN, OR = 0.943, 95% CI 0.903 to 0.985, P = 0.009) and higher ratio of low to high frequency power (LF/HF, OR = 4.372, 95% CI 1.033 to 18.508, P = 0.045) during the sleep period were associated with CSVD, independent of traditional cerebrovascular risk factors and sleep disordered breathing. A number of 24 CSVD patients and 21 controls further underwent three-dimensional brain volume scan and VBM analysis. Based on VBM results, SDNN during the awake time (β = 0.544, 95% CI 0.211 to 0.877, P = 0.001) and the sleep period (β = 0.532, 95% CI 0.202 to 0.862, P = 0.001) were both positively related with gray matter volume within the right inferior frontal gyrus only among CSVD patients.ConclusionsDecreased nocturnal HRV is associated with arteriosclerotic CSVD independent of traditional cerebrovascular risk factors and sleep disordered breathing. The structural atrophy of some brain regions associated with cardiac autonomic regulation sheds light on the potential relationship.Trial registrationTrial registration number: ChiCTR1800017902. Date of registration: 20 Aug 2018.