Average Heart Research Articles

FEASIBILITY OF WATCH-TYPE CUFF-LESS BLOOD PRESSURE MEASUREMENT DEVICE IN DAILY BLOOD PRESSURE MONITORING

Objective: Cuff-less blood pressure (BP) measurement devices integrated into smartwatches have gained prominence for daily monitoring, yet limited studies provide the analysis of real-world BP data collected by such devices. In this study, we evaluated the feasibility of photoplethysmographic BP measuring smartwatch by analyzing data collected in real-world. Design and method: The campaign, “Smartwatch Blood Pressure Monitoring Challenge with Korean Hypertension Society”, was held in June 1-14, 2023 and 896 participants reported 35592 BP values measured by smartwatch (Samsung Galaxy Watch 6, approved in Korean Ministry of Food and Drug Safety). Participants were instructed to measure BP daily, in the morning (5AM-8AM) and evening (6PM-9PM) for two weeks, with initial calibration and re-calibration after the first week. We evaluated 1) BP difference between before and after re-calibration, and 2) difference in morning and evening BP. We also evaluated the determining factors of the BP differences. Results: Morning and evening BP values showed significant difference, higher in the evening by 1.42±5.25 mmHg (p<0.05). However, the diurnal variation was much smaller than reported in other studies using conventional BP monitoring devices. ANOVA identified significant variables for evening-morning differences, including basal metabolic rate, skeletal muscle mass, total body water, average systolic BP (SBP), diastolic BP (DBP), and heart rate in the morning (p < 0.01 in both ITT and PP). Participants who have evening-morning difference higher than the third quartile, where evening SBP was significantly higher than morning SBP, exhibited smaller variable sizes. Turkey’s Honest Significant Difference showed that this relationship is statistically significant between Q1-Q4 and Q2-Q4 in all variables. The calibration stability was assessed by the difference in average BP before and after calibration, resulting in an SBP difference of 4.64±4.73 mmHg and DBP of 3.66±3.62 mmHg, smaller than a 2021 campaign (6.8±5.6mmHg). When the difference of average was measured between same period of time (morning versus morning and evening versus evening), SBP of 5.39±5.22 mmHg and DBP of 4.3±3.99 mmHg. Conclusions: In conclusion, watch-based devices may not detect clinical-level BP variability, but refining calibration protocols offers improvement potential.

Effects of acute whole-body and lower limb heating on hemodynamic responses to walking in patients with peripheral artery disease

Background: The exercise pressor reflex is exaggerated in patients with peripheral artery disease (PAD). There has been speculation regarding cardiovascular benefits of heating therapy for patients with PAD. The impact of acute leg heating and whole-body heating on hemodynamic responses during walking remains incompletely understood. The purpose of this study was to evaluate the effects of acute whole-body and lower leg heating on hemodynamic responses to walking in both patients with PAD and healthy control subjects. Hypothesis: We hypothesized that both acute whole-body and lower leg heating would attenuate the pressor response to walking in patients with PAD. Methods: 10 PAD patients (68 ± 7 yrs; Male/Female, N = 7/3) and 8 age-matched healthy control subjects (64 ± 5 yrs, Male/Female, N = 5/3) participated in this study. The treadmill walking test followed the Gardner protocol, involving a constant speed of 2 mph with a 2%-grade increment every 2 minutes. The study encompassed 3 trials/visits: 1) non-heating (control), 2) post leg heating, and 3) post whole-body heating. The order of these visits was randomized. During the leg heating visit, the subjects' lower limbs (below the knees) were immersed in warm water (40-42℃) for 30 minutes. Whole-body heating was administered by outfitting the subjects in a tube-lined heating suit until their internal temperature increased by 0.3℃ (~ 45 min). Hemodynamic responses were assessed by comparing the average systolic blood pressure (SBP) and heart rate (HR) during the last 3 stages of treadmill walking with baseline values. Results: Resting SBP and HR did not exhibit significant differences between groups (all P > 0.05). During the control visit, the increase in SBP due to treadmill walking was significantly (P = 0.04) higher in patients with PAD than in healthy subjects. No group differences were observed in the increase in HR by treadmill walking. The responses in SBP and HR to treadmill walking, following leg heating, were comparable to those observed in the control visit for both groups (all P > 0.05). Compared to the control visit, whole-body heating significantly attenuated the SBP (ΔSBP%, 32.9 ± 13.5 vs. 21.3 ± 9.5 %, P = 0.02) and HR responses (ΔHR%, 61.6 ± 24.3 vs. 42.7 ± 15.6 %, P = 0.03) to treadmill walking in PAD. However, in healthy subjects after whole-body heating, these responses were not different from the control visit (both P > 0.05). Neither whole-body nor leg heating had any impact on the walking distance in patients with PAD. Discussion and Conclusion: Acute whole-body heating significantly attenuated the pressor response to walking in patients with PAD, while lower leg heating exhibited no such impact. These findings suggest potential benefits of acute whole-body heating for patients with PAD. We speculate that the comprehensive systemic adjustments by whole-body heat exposure play a pivotal role in improving the exaggerated pressor response to exercise in PAD. Conversely, local lower leg heating, as observed in our study, seems insuffcient to change the hemodynamic response to exercise in patients with PAD. This study was supported by NIH R01 HL141198 and R01 HL144781. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

The Association Between Physical Activity/Heart Rate Variability Data Obtained Using a Wearable Device and Timed Motor Functional Tests in Patients with Duchenne Muscular Dystrophy: A Pilot Study.

Duchenne muscular dystrophy (DMD) is a devastating X-linked muscle disease. Clinical evaluation of DMD uses patient-intensive motor function tests, and the recent development of wearable devices allows the collection of a variety of biometric information, including physical activity. In this study, we examined differences in physical activity and heart rate variability (HRV) between patients with DMD and healthy subjects using a wearable device, and investigated any association between these parameters and motor function in patients with DMD. Participants were 7 patients with DMD and 8 healthy males, whose physical activity and HRV were provided by a wearable device. These data were used to investigate the relationship between both physical activity and HRV parameters and timed motor functional tests [Time to stand from supine, 10-meter walking time (10MWT), North Star Ambulatory Assessment (NSAA), and 6-minute walking test (6MWT)] in patients with DMD. Results of 24-hours physical activity, fat burning, total number of steps and active distance, average step rate, average exercise intensity during walking, exercise, degree of forward lean during walking, maximum heart rate, normalized low frequency power (LF norm), and maximum exercise intensity in patients with DMD were lower than those in control subjects. Physical activity and HRV parameters did not correlate with the time to stand from supine. The 10MWT positively correlated with average heart rate, while NSAA negatively correlated with average heart rate, total frequency power (TF), and very low frequency power (VLF) during arousal. The 6MWT negatively correlated with ratio LF/high frequency power (HF). Physical activity and HRV indices that differ from those of normal children and that correlate with motor function assessment may serve as digital biomarkers.

Study of The Physiological Status of Horses Before and After Training in Anantya Riding Club

Background: The physiological status of a horse is an indicator of its health. Parameters that can be used to determine the health status of a horse include respiratory rate, heart rate, and body temperature. As the activity of a horse increases, its respiratory rate increases. By measuring respiratory rate, heart rate, and body temperature before and after training, changes in the physiological status of a horse can be determined. Purpose: This study aims to provide an overview of the physiological status of horses before and after training at Anantya Riding Club. Case: Physiological status of horses before and after training. Case Management: This study used a qualitative approach. Data on the physiological conditions of horses were collected before and after training. A digital thermometer was used to measure body temperature. A stethoscope was used to measure heart rate. Respiratory rate was measured by placing the back of the hand or the palm of the hand close to the horse's nose to feel its breath. These measurements were taken before and after training. Conclusion: This study concluded that the physiological status of horses after training showed an improvement. The average body temperatures of the horses before and after training were [37.6 ± 0.09]°C and [38.61 ± 0.03] °C, respectively. The average heart rates of the horses before and after training were 41.0 ± 2.4 beats/minute and 90.2 ± 3.5 beats/minute, respectively. Finally, the average respiratory rates of the horses before and after training exercise were 39.7 ± 3.0 breaths/minute and 101.2 ± 0.5 breaths/minute, respectively.

Use of machine learning and Poincaré density grid in the diagnosis of sinus node dysfunction caused by sinoatrial conduction block in dogs.

Sinus node dysfunction because of abnormal impulse generation or sinoatrial conduction block causes bradycardia that can be difficult to differentiate from high parasympathetic/low sympathetic modulation (HP/LSM). Beat-to-beat relationships of sinus node dysfunction are quantifiably distinguishable by Poincaré plots, machine learning, and 3-dimensional density grid analysis. Moreover, computer modeling establishes sinoatrial conduction block as a mechanism. Three groups of dogs were studied with a diagnosis of: (1) balanced autonomic modulation (n = 26), (2) HP/LSM (n = 26), and (3) sinus node dysfunction (n = 21). Heart rate parameters and Poincaré plot data were determined [median (25%-75%)]. Recordings were randomly assigned to training or testing. Supervised machine learning of the training data was evaluated with the testing data. The computer model included impulse rate, exit block probability, and HP/LSM. Confusion matrices illustrated the effectiveness in diagnosing by both machine learning and Poincaré density grid. Sinus pauses >2 s differentiated (P < .0001) HP/LSM (2340; 583-3947 s) from sinus node dysfunction (8503; 7078-10 050 s), but average heart rate did not. The shortest linear intervals were longer with sinus node dysfunction (315; 278-323 ms) vs HP/LSM (260; 251-292 ms; P = .008), but the longest linear intervals were shorter with sinus node dysfunction (620; 565-698 ms) vs HP/LSM (843; 799-888 ms; P < .0001). Number and duration of pauses, not heart rate, differentiated sinus node dysfunction from HP/LSM. Machine learning and Poincaré density grid can accurately identify sinus node dysfunction. Computer modeling supports sinoatrial conduction block as a mechanism of sinus node dysfunction.

Validity and reliability of the VXSport (Omni) device on basketball movement parameters

The use of inertial devices in sport have become increasingly common. The aim of this study was to examine the within-day validity and reliability of a relatively new inertial measurement unit at measuring basketball movement parameters. Eighteen well-trained basketball players completed several individual performance tests including linear running and change of directions, acceleration, and decelerations, jumping and impacts to measure the validity and reliability of the microtechnology. The players also completed a specific test called the Basketball Exercise Simulation Test (BEST) to investigate whether the microtechnology could accurately detect more dynamic movements. Pearsons’s correlations were determined linking assessments of the practical measures taken from the inertial measurement unit to criterion measures. Testing revealed good validity between the microtechnology and criterion measures with the 20 m run test at various velocities (6 km.h-1, 12 km.h-1, 18 km.h-1, 24 km.h-1, maximal speed km.h-1 (mean bias &lt;5%). However, total distance, body collisions, accelerations and decelerations showed lower validity (mean bias &gt;10%). Total distance, number of sprints, number of sprints &gt;15 km.h-1, number of decelerations &gt;3m.s-2, number of accelerations and decelerations showed very large to nearly perfect reliability (ICC = 0.88 – 0.99). Whereas, relative distance (m.min-1), maximal speed (km.h-1), total number of accelerations (&gt;3 m.s-2), total number of jumps, average heart rate showed high reliability (ICC 0.77 – 0.87). These results demonstrate the units were able to accurately detect most basketball movement patterns correctly with good repeatability.

Cardiovascular Demand Differences Between Male and Female US Marine Recruits During Progressive Loaded Hikes.

Schram, B, Orr, R, Niederberger, B, Givens, A, Bernards, J, and Kelly, KR. Cardiovascular demand differences between male and female US Marine recruits during progressive loaded hikes. J Strength Cond Res 38(8): e454-e458, 2024-Despite having to carry the same occupational load, female soldiers tend to be lighter than male soldiers. The aim of this study was to determine the differences in cardiovascular load between female and male US Marine recruits during progressive load carriage hikes. United States Marine Corps recruits (565 male recruits; 364 female recruits) completed 6 loaded hikes over 6 weeks (1: 10 kg, 30 minutes; 2: 10 kg, 45 minutes; 3: 15 kg, 30 minutes, 4: 15 kg, 45 minutes; 5: 20 kg, 30 minutes; 6: 20 kg, 45 minutes) during which cardiovascular response was measured. Average heart rate (HRavg), HR maximum (HRmax), and pace were measured via a wrist-worn physiological monitor. Independent sample t -tests were conducted to compare between sexes, with significance set at 0.008 after adjusting for multiple comparisons. The average female recruit had significantly lower body mass (BM) compared with the average male recruit ( p < 0.001) and thus carried a significantly heavier relative load. (10 kg ∼17%, 15 kg ∼25%, 20 kg ∼33%, p < 0.001). There were no significant differences in pace in any hike, and no significant differences were found in HRavg or HRmax when comparing female and male Marines during Hike 1. For female Marines, HRavg was significantly higher compared with male Marines during Hike 2 (+6.5 b·min -1 , p < 0.001) and Hike 3 (+7.4 b·min -1 , p < 0.001), and both HRavg and HRmax were significantly higher in Hike 4 (+11.9 b·min -1 , +8.4 b·min -1 , p < 0.001), Hike 5 (+7.7 b·min -1 , +7.9 b·min -1 , p < 0.001), and Hike 6 (+6.9 b·min -1 , +7.1 b·min -1 , p < 0.001), respectively. Female Marines endured greater cardiovascular demand compared with male Marines during load carriage events when carrying loads greater than 15 kg (∼25% BM).

A Multimodal Exertional Test for concussion: a pilot study in healthy athletes.

Exertional tests have become a promising tool to assist clinicians in the management of concussions, however require expensive equipment, extensive spaces, and specialized clinician expertise. As such, we developed a test with minimal resource requirements encompassing key elements of sport and physical activity. The purpose of this study was to pilot test the Multimodal Exertional Test (MET) protocol in a sample of healthy interuniversity athletes. The MET comprises four stages, each featuring three distinct tasks. The test begins with engaging in squats, alternating reverse lunges, and hip hinges (Stage 1). The next stage progressively evolves into executing these tasks within specified time limits (Stage 2). Following this, the test advances to a stage that incorporates cognitive tasks (Stage 3), and the final stage demands greater levels of physical exertion, cognition, and multi-directional movements (Stage 4). Heart rate (HR) was obtained during each stage of the MET and participants' symptom severity scores were recorded following each task. Fourteen healthy interuniversity athletes (n = 8 female, n = 6 male) participated in the study. HR was obtained for 10 of the 14 athletes (females: n = 6, males: n = 4). Increases in average and maximum HR were identified between pre-MET and Stage 1, and between Stages 3 and 4. Consistent with the tasks in each stage, there were no increases in average and maximum HR observed between MET Stages 1 to 3. Female athletes exhibited higher average and maximum HRs compared to male athletes during all four stages. All 14 athletes reported minimal changes in symptom severity following each task. Among healthy athletes, the MET elicits an increase in average and maximum HR throughout the protocol without symptom provocation. Female athletes exhibit higher HRs during all four stages in comparison to male athletes.

Assessment of Heart Rate Variability in Children with Mitral Valve Prolapse.

Mitral valve prolapse (MVP) is a heart valve anomaly with specific electrocardiographic findings and arrhythmia. A predominant sympathetic tone and diminished vagal activity have been reported especially in symptomatic MVP patients. In the current study, we aim to review heart rate variability (HRV) parameters of MVP children in order to determine if there is an impaired autonomic regulation. The data of children with MVP were retrospectively analyzed. Demographic characteristics, body mass index, symptomatology, MVP type and mitral regurgitation, MVP-related electrocardiographic changes, arrhythmia, and HRV parameters in 24-h Holter monitoring were recorded. HRV parameters of the control group were obtained from children applying for sport participation. Statistical significance limit was accepted as p < 0.05. 154 of the patients (74.8%) were girls, the median age was 13.58 ± 2.99years. While MVP patients had shorter PR intervals, those who had syncope had longer PR intervals. Short PR distance may be a feature of MVP, long PR distance may be a condition associated with syncope with the underlying paroxysmal atrioventricular block. Moreover, the minimum heart rate was significantly lower in the MVP group compared to the control and there were no significant differences in terms of remaining parameters. The number of low LF values was higher in MVP patients than the control. Comparing HRV values of groups by gender, we found that overall HRV parameters were lower in girls with MVP while minimum, maximum, and average heart rate were lower in boys with MVP. Impaired HRV associated with MVP could be age, gender, and symptom related. In addition, low LF may indicate impaired baroreflex sensitivity in MVP patients.

Heart Rate Acceleration and Deceleration Capacities Associated With 24-Hour Circadian Blood Pressure Variation of Hypertension Patients

Abstract OBJECTIVE To observe the relationship between 24-hour ambulatory blood pressure circadian rhythm and heart rate acceleration (AC), deceleration capacities (DC) in patients with hypertension. METHODS A total of 198 patients with essential hypertension were included and were monitored by 24-hour ambulatory blood pressure. Based on the nocturnal decline rate of systolic blood pressure, patients were divided into 2 groups: dippers (decline rate 10%–20%, n = 58) and non-dippers (decline rate &amp;lt;10%, n = 140). DC and AC values were calculated based on dynamic electrocardiogram data and compared between 2 groups. Pearson correlation analysis was used to analyze the correlation between DC, AC, and blood pressure and circadian blood pressure variation. Multivariate logistic regression analysis was used to analyze the influencing factors of non-dippers. RESULTS Compared with dippers, AC increased, while DC, standard deviation of normal R–R intervals (SDNN), percentage of heart beats with difference between adjacent normal RR intervals &amp;gt;50 ms in the total number of NN intervals (PNN50%) decreased in non-dippers (P &amp;lt; 0.05). Pearson analysis showed that AC was positively correlated to nighttime systolic blood pressure (r = 0.297), slowest heart rate (r = 0.221) and negatively correlated to SDNN (r = −0.233) and PNN50 (r = −0.238), while DC was negatively correlated to nighttime systolic blood pressure (r = −0.300), 24-hour average heart rate (r = −0.144), slowest heart rate (r = −0.213), and positively correlated to SDNN (r = 0.230), PNN50 (r = 0.267) (all P &amp;lt; 0.05). Multivariate logistic regression analysis showed that in the model included AC, AC (odds ratio [OR] = 1.320, 95% confidence interval [CI] 1.102–1.580, P = 0.003), age (OR = 1.029, 95% CI 1.001–1.057, P = 0.039), and 24-hour average heart rate (OR = 1.062, 95% CI 1.010–1.116, P = 0.02) were independent risk factors for non-dippers, while in the model included DC, DC (OR = 0.824, 95% CI 0.709–0.956, P = 0.011), age (OR = 1.027, 95% CI 1.001–1.055, P = 0.046), and 24-hour average heart rate (OR = 1.058, 95% CI 1.007–1.113, P = 0.025) were independent risk factors for non-dippers. CONCLUSIONS AC increases and DC decreases in patients with non-dipper hypertension. Nighttime systolic blood pressure positively correlates with AC and negatively correlates with DC. AC and DC are independent risk factors for abnormal circadian rhythm of blood pressure in hypertensives.

Partial Resistance to Thyroid Hormone-Induced Tachycardia and Cardiac Hypertrophy in Mice Lacking Thyroid Hormone Receptor β.

Background: Thyroid hormones regulate cardiac functions mainly through direct actions in the heart and by binding to the thyroid hormone receptor (TR) isoforms α1 and β. While the role of the most abundantly expressed isoform, TRα1, is widely studied and well characterized, the role of TRβ in regulating heart functions is still poorly understood, primarily due to the accompanying elevation of circulating thyroid hormone in TRβ knockout mice (TRβ-KO). However, their hyperthyroidism is ameliorated at thermoneutrality, which allows studying the role of TRβ without this confounding factor. Methods: Here, we noninvasively monitored heart rate in TRβ-KO mice over several days using radiotelemetry at different housing temperatures (22°C and 30°C) and upon 3,3',5-triiodothyronine (T3) administration in comparison to wild-type animals. Results: TRβ-KO mice displayed normal average heart rate at both 22°C and 30°C with only minor changes in heart rate frequency distribution, which was confirmed by independent electrocardiogram recordings in freely-moving conscious mice. Parasympathetic nerve activity was, however, impaired in TRβ-KO mice at 22°C, and only partly rescued at 30°C. As expected, oral treatment with pharmacological doses of T3 at 30°C led to tachycardia in wild-types, accompanied by broader heart rate frequency distribution and increased heart weight. The TRβ-KO mice, in contrast, showed blunted tachycardia, as well as resistance to changes in heart rate frequency distribution and heart weight. At the molecular level, these observations were paralleled by a blunted cardiac mRNA induction of several important genes, including the pacemaker channels Hcn2 and Hcn4, as well as Kcna7. Conclusions: The phenotyping of TRβ-KO mice conducted at thermoneutrality allows novel insights on the role of TRβ in cardiac functions in the absence of the usual confounding hyperthyroidism. Even though TRβ is expressed at lower levels than TRα1 in the heart, our findings demonstrate an important role for this isoform in the cardiac response to thyroid hormones.

Estimating metabolic rate from ISO heart rate method and two walking equations.

Assigning a value for metabolic rate is central to heat stress assessment. ISO 8996 describes a predictive method for walking based on the American College of Sports Medicine (ACSM) method and another generalized method based on average heart rate. In addition, the US Army uses the load carriage decision aid (LCDA) predictive equation to estimate metabolic rate. The purpose of this study was to assess the accuracy/bias and precision of the ISO heart rate method and the ACSM and LCDA equations. The laboratory database included metabolic rate, heart rate, treadmill speed, and grade during a progressive heat stress protocol. Treadmill speed and grade were set to represent one of three metabolic rates. Accuracy and precision were assessed with Bland-Altman plots. All three methods had good accuracy (low bias). For precision, the ISO heart rate method had a root mean square error (RMSE) of 34 W and 11% when adjusted for repeated measures. The RMSE for two equations was 20 W and 7%. Although the heart method had less accuracy, its application is more generalizable. The heart rate method should be used below the occupational exposure limit for heat stress to avoid a bias toward higher predicted values due to heat strain.

Analysis of Sleep, Nocturnal Physiology, and Physical Demands of NCAA Women's Ice Hockey Across a Championship Season.

Merrigan, JJ, Stone, JD, Kraemer, WJ, Friend, C, Lennon, K, Vatne, EA, and Hagen, JA. Analysis of sleep, nocturnal physiology, and physical demands of NCAA women's ice hockey across a championship season. J Strength Cond Res 38(4): 694-703, 2024-The aims of this study were to evaluate the (a) relationships between daily physical demands and nighttime sleep, heart rate (HR), and heart rate variability (HRV); (b) weekly changes in physical demands and sleep; and (c) differences among positions and between training and competition during a competitive season in National Collegiate Athletic Association (NCAA) women's ice hockey. Twenty-five NCAA Division I women's ice hockey athletes wore a sensor at night to monitor sleep quantity or quality (e.g., time asleep and sleep efficiency) and physiology (e.g., HR and HRV). During training and competitions (31 regular season and 7 postseason), athletes wore performance monitoring systems to assess workload demands (e.g., training impulse and TRIMP). As internal workload (TRIMP, Time >80% of HRmax, Average HR) during training or competition increased, nocturnal HRV decreased, HR increased, and Sleep Duration, Sleep Score, and Readiness Score decreased that night. Across the season, athletes experienced lower HRV, but exhibited longer sleep durations. Training Distance, Duration, Time >80% HRmax, Average HR, and TRIMP decreased, whereas competition Total Distance, Duration, and TRIMP increased across weeks throughout the season. There were differences across positions and season blocks when evaluating these data at the mesocycle level. Athletes slept longer before competition compared with training, but physiological data did not differ. Competitions had greater physiological demands than training. We speculate that the increased focus on sleep hygiene, as evidenced by the increase in sleep over the season, may have served as a recovery aid to combat physiological stress of accumulated demands of competitions that increased over time into postseason tournaments.

Physiological and metabolic responses of Parabadminton athletes to field simulated effort.

Due to the increase in the number of Parabadminton (PBd) athletes and the lack of scientific knowledge of the sport, it is important to evaluate performance variables in different game stimuli. Thus, this study sought to examine the physiological and metabolic responses in a simulated effort protocol in PBd athletes. Forty-seven volunteers (WH1=7; WH2=9; SL3=8; SL4=9; SU5=6; SH6=8) performed a simulated effort protocol, consisting of 2 blocks of activities (1st change of direction + 1st simulated effort; 2nd change of direction + 2nd simulated effort). Peak and average oxygen consumption (VO<inf>2</inf>peak and VO<inf>2</inf>avg), peak, percentage, and average heart rate (HRmax, %HRmax, and HRavg), percentage of carbohydrates and lipids contributions (%CARB and %FAT), and average and total energy expenditure (EEavg and EEtotal) were evaluated. The data was compared between protocol stages, functional classes (FCs), and court size. It was adopted P<0.05. Differences were found between the stages of the protocol in VO<inf>2</inf>peak (P=0.0008), VO<inf>2</inf>avg (P=0.0004); HRmax (P<0.0001); %HRmax (P=0.0001), HRavg (P=0.0001), %CARB (P=0.0001), %FAT (P=0.0001), EEavg (P=0.0002), and EEtotal (P=0.008). Among FCs, SL4 athletes were superior to WH1 athletes for VO<inf>2</inf>peak (P=0.075), VO<inf>2</inf>avg (P=0.022), EEavg (P=0.011), and EEtotal (P=0.022). Athletes who completed protocol in the full court were greater than half court for VO<inf>2</inf>peak (P<0.001), VO<inf>2</inf>avg (P<0.001), %HRmax (P=0.032), HRavg (P=0.018), %CARB (P=0.022), %FAT (P=0.022), and EEavg (P=0.016). PBd athletes belonging to higher FCs (4, 5, and 6) and who cover greater distances on the court exhibit physiological and metabolic responses under greater influence of the type of disability.

Optimization system for training efficiency and load balance based on the fusion of heart rate and inertial sensors

ObjectivesTo enhance the daily training quality of athletes without inducing significant physiological fatigue, aiming to achieve a balance between training efficiency and load. Design methodsFirstly, we developed an activity classification training model using the random forest algorithm and introduced the “effective training rate” (the ratio of effective activity time to total time) as a metric for assessing athlete training efficiency. Secondly, a method for rating athlete training load was established, involving qualitative and quantitative analyses of physiological fatigue through subjective fatigue scores and heart rate data. Lastly, an optimization system for training efficiency and load balance, utilizing multiple inertial sensors, was created. Athlete states were categorized into nine types based on the training load and efficiency ratings, with corresponding management recommendations provided. ResultsOverall, this study, combining a sports activity recognition model with a physiological fatigue assessment model, has developed a training efficiency and load balance optimization system with excellent performance. The results indicate that the prediction accuracy of the sports activity recognition model is as high as 94.70%. Additionally, the physiological fatigue assessment model, utilizing average relative heart rate and average RPE score as evaluation metrics, demonstrates a good overall fit, validating the feasibility of this model. ConclusionsThis study, based on relative heart rate and wearable devices to monitor athlete physiological fatigue, has developed a balanced optimization system for training efficiency and load. It provides a reference for athletes’ physical health and fatigue levels, offering corresponding management recommendations for coaches and relevant professionals.

Heart Rate Variability Monitoring Based on Doppler Radar Using Deep Learning.

The potential of microwave Doppler radar in non-contact vital sign detection is significant; however, prevailing radar-based heart rate (HR) and heart rate variability (HRV) monitoring technologies often necessitate data lengths surpassing 10 s, leading to increased detection latency and inaccurate HRV estimates. To address this problem, this paper introduces a novel network integrating a frequency representation module and a residual in residual module for the precise estimation and tracking of HR from concise time series, followed by HRV monitoring. The network adeptly transforms radar signals from the time domain to the frequency domain, yielding high-resolution spectrum representation within specified frequency intervals. This significantly reduces latency and improves HRV estimation accuracy by using data that are only 4 s in length. This study uses simulation data, Frequency-Modulated Continuous-Wave radar-measured data, and Continuous-Wave radar data to validate the model. Experimental results show that despite the shortened data length, the average heart rate measurement accuracy of the algorithm remains above 95% with no loss of estimation accuracy. This study contributes an efficient heart rate variability estimation algorithm to the domain of non-contact vital sign detection, offering significant practical application value.

Increased patient body mass index is associated with increased surgeon physiologic stress during total hip arthroplasty.

While increased body mass index (BMI) in patients undergoing total hip arthroplasty (THA) increases surgical complexity, there is a paucity of objective studies assessing the impact of patient BMI on the cardiovascular stress experienced by surgeons during THA. The aim of this study was to assess the impact of patient BMI on surgeon cardiovascular strain during THA. We prospectively evaluated three fellowship-trained arthroplasty surgeons performing a total of 115 THAs. A smart-vest worn by the surgeons recorded mean heart rate, stress index (correlate of sympathetic activation), respiratory rate, minute ventilation, and energy expenditure throughout the procedures. Patient demographics as well as perioperative data including surgical approach, surgery duration, number of assistants, and the timing of the surgery during the day were collected. Linear regression was utilized to assess the impact of patient characteristics and perioperative data on cardiorespiratory metrics. Average surgeon heart rate, energy expenditure, and stress index during surgery were 98.50 beats/min, 309.49cal/h, and 14.10, respectively. Higher patient BMI was significantly associated with increased hourly energy expenditure (P = 0.027), mean heart rate (P = 0.037), and stress index (P = 0.027) independent of surgical approach. Respiratory rate and minute ventilation were not associated with patient BMI. The number of assistants and time of surgery during the day did not impact cardiorespiratory strain on the surgeon. The physiologic burden on surgeons during primary THA significantly increases as patient BMI increases. This study suggests that healthcare systems should consider adjusting reimbursement models to account for increased surgeon workload due to obesity. Further surgeons should adopt strategies in operative planning and case scheduling to handle this added physical strain. III.

How Elite Athletes with a Spinal Cord Injury Sweat during Exercise-An Exploratory Study.

Sweat and thermal responses in individuals with spinal cord injury (SCI) are impaired depending on lesion characteristics. This is particularly problematic for athletes and may ultimately lead to reduced performance. This exploratory study investigated the feasibility of field-usable methods to objectively collect data relevant to sweat response in elite athletes with SCI. Differences in sweat response were also evaluated for different athlete characteristics. Measurements were performed during exercise and included core temperature (Tc), heart rate, urine specific gravity, fluid intake, sweat rate, and sweat electrolyte concentration. Differences for sex, lesion level (tetraplegia versus paraplegia), motor impairment (complete versus incomplete), and sport type (endurance versus team/skill) were evaluated. Fifteen athletes (median (Q1-Q3) age, 30 (28-36) years; three females; 11 with complete lesions) were included. Endurance athletes were measured during indoor performance tests (n = 10), whereas team/skill athletes were measured during training sessions (n = 5). In the mixed exercise intensities, the average Tc was 37.7 (37.3-37.8) °C and the average heart rate was 126 (100-146) bpm. Dehydration, defined as a urine specific gravity > 1.020 ng/mL, was prevalent in six athletes before exercise and in five athletes after exercise. The sweat rate was lower in athletes with tetraplegia (p = 0.02) and in team/skill athletes (p = 0.008). Collecting sweat and thermal response data from athletes with SCI in the field is feasible. Given the suboptimal hydration status of many athletes, raising awareness of the importance of hydration seems valuable.

Heart rate variability and its association with symptoms of orthostatic hypotension in spinal cord injury

Context/objective To assess differences in autonomic function using heart rate variability (HRV) parameters between people with and without orthostatic hypotension (OH), and to determine symptoms of OH in people with spinal cord injury (SCI). Methods R-R interval and blood pressure (BP) data were recorded using Finometer PRO® in both the supine position and at a 60-degree tilt using a tilt table, each lasting for 6 minutes. R-R interval data were processed using the Kubios HRV analysis software to convert R-R interval into time and frequency domains for further analysis. Results Compared to the non-OH group, the SCI group with OH exhibited lower values for root mean square of the successive differences (RMSSD) and standard deviation of normal-to-normal interval (SDNN), along with an elevated heart rate during tilt-up. Participants with OH symptoms had a lower average heart rate in the supine and 60-degree positions compared to asymptomatic participants. Logistic regression analysis indicated that SDNN in the supine position correlated with the presence of OH, and that the mean heart rate in the 60-degree position was related to the presence of symptoms. Conclusions Differences in HRV parameters were observed in people with SCI and OH, suggesting a reduced parasympathetic activity in the supine position, likely as a response to maintain homeostasis in BP regulation. Despite the presence or absence of OH symptoms, there was no difference in HRV parameters. This finding suggests that autonomic function may not be the primary determinant of these symptoms, with other factors likely being more influential.

Enhancing walking efficiency of adolescents with neurological impairments using an exosuit for ambulatory activities of daily living.

Introduction: Children and adolescents with neurological impairments face reduced participation and independence in daily life activities due to walking difficulties. Existing assistive devices often offer insufficient support, potentially leading to wheelchair dependence and limiting physical activity and daily life engagement. Mobile wearable robots, such as exoskeletons and exosuits, have shown promise in supporting adults during activities of daily living but are underexplored for children. Methods: We conducted a cross-sectional study to examine the potential of a cable-driven exosuit, the Myosuit, to enhance walking efficiency in adolescents with diverse ambulatory impairments. Each participant walked a course including up-hill, down-hill, level ground walking, and stairs ascending and descending, with and without the exosuit's assistance. We monitored the time and step count to complete the course and the average heart rate and muscle activity. Additionally, we assessed the adolescents' perspective on the exosuit's utility using a visual analog scale. Results: Six adolescents completed the study. Although not statistically significant, five participants completed the course with the exosuit's assistance in reduced time (time reduction range: [-3.87, 17.42]%, p-value: 0.08, effect size: 0.88). The number of steps taken decreased significantly with the Myosuit's assistance (steps reduction range: [1.07, 15.71]%, p-value: 0.04, effect size: 0.90). Heart rate and muscle activity did not differ between Myosuit-assisted and unassisted conditions (p-value: 0.96 and 0.35, effect size: 0.02 and 0.42, respectively). Participants generally perceived reduced effort and increased safety with the Myosuit's assistance, especially during tasks involving concentric contractions (e.g., walking uphill). Three participants expressed a willingness to use the Myosuit in daily life, while the others found it heavy or too conspicuous. Discussion: Increased walking speed without increasing physical effort when performing activities of daily living could lead to higher levels of participation and increased functional independence. Despite perceiving the benefits introduced by the exosuit's assistance, adolescents reported the need for further modification of the device design before using it extensively at home and in the community.