Heart Rate Variables Research Articles

Effects of a Combined Method of Normobaric Hypoxia on the Repeated Sprint Ability Performance of a Nine-Time World Champion Triathlete: A Case Report

Elite athletes are an under-represented population in scientific studies, and there are no works analysing the influence of hypoxia in elite triathletes. The aim of this study was to analyse the influence of different methods of normobaric hypoxia on repeated sprint ability (RSA) performance. This study was a case study with an elite triathlete who has won nine triathlon world championships. The study used a combination of different methods of normobaric hypoxia. The three methods combined were as follows: live high-train low interspersed; intermittent hypoxic training; and intermittent hypoxic exposure. This study analysed the influence of these methods on RSA performance in variables such as power output, saturation of muscular oxygen, heart rate and ventilatory variables (VO2 and VCO2). The triathlete was measured before the training protocol (PRE), just after (POST-D3) and 21 days after the end of the protocol (POST-D21). This type of protocol has shown that it can lead to an improvement in RSA performance in the number of sprints (PRE vs. POST-D3 vs. POST-D21: 19 vs. 24 vs. 28), power output (PRE 615 W vs. POST-D3 685 W vs. POST-D21 683W) and efficiency of the triathlete. This work may be useful in improving power output and repeated sprint ability for elite triathletes.

Development of an ultrasound-based clinical decision rule to rule-out diverticulitis

The concern for diverticulitis often leads to the use of computed tomography (CT) scans for diagnosis. We aim to develop an ultrasound-based clinical decision rule (CDR) to confidently rule-out the disease without requiring a CT scan. We analyzed data from a prospective study of adult emergency department (ED) patients with suspected diverticulitis who underwent both bedside ultrasound (US) and CT. Patient history, physical examination, laboratory findings, and US results were used to create a CDR via a recursive partitioning model designed to prioritize sensitivity, with a loss matrix heavily penalizing false negatives. We calculated the test characteristics for this CDR (TICS-Rule) and assessed the potential reduction in CT scans and ED length of stay. Data from 149 patients (84 female; mean age 58 ± 16) were used to develop the TICS-Rule. The final model integrates US diagnosis of simple and complicated diverticulitis, along with variables of heart rate, age, history of diverticulosis, vomiting, and leukocytosis. Negative US results and a heart rate below 100 effectively excluded diverticulitis. The sensitivity increased from 54.5% (32.2–75.6) in the US alone to 100% (84.6–100%) for complicated diverticulitis in the model. The TICS-Rule missed no cases of complicated diverticulitis but one case of simple diverticulitis. The median time from ED greeting to US interpretation was 103 min (IQR 62–169), compared to 285 min (IQR 229–372) for CT. The TICS-Rule uses a combination of negative US and heart rate less thanQ1 100 to exclude diverticulitis without the need for a CT scan. Integration of the TICS-Rule offers a promising enhancement to clinical decision-making while reducing both CT use and ED length of stay.

Heart rate response and recovery in bicycle exercise testing - reference values and association with mortality

Abstract Introduction Chronotropic incompetence and impaired heart rate (HR) recovery are related to mortality. Guidelines lack specific recommendations for reference values on HR recovery assessment. Purpose To define normal values for HR response and recovery in individuals referred for a bicycle exercise stress test and to relate these factors to risk of mortality. Methods We included 9,917 subjects (46% females) aged 18–85 years who performed a bicycle exercise test. We defined age- and sex-specific reference equations for peak HR, HR reserve, and HR recovery at 1 and 2 minutes (HRR1 and HRR2) using a subgroup of individuals without apparent cardiovascular (CV) risk nor comorbidities (N=2,774). Associations between blunted HR indices (<5thpercentile) and mortality were analysed using Cox regression in all subjects and in individuals with normal exercise capacity (N=8,070). Results All HR indices were age-dependent. The 5th percentiles of HR reserve, HRR1, and HRR2 correlated weakly with previously reported reference values. During median follow-up of 8.6 years 1,110 (11%) died. HR recovery variables were the strongest predictors of all-cause (HRR1, hazard ratio 1.66 (95% confidence interval, 1.45–1.90)) and CV mortality (HRR2, 1.59 (1.26–2.00)) after adjustments for potential confounders. Blunted HR response (peak HR) increased risk of all-cause (1.32 (1.14–1.53)) and CV mortality (1.41 (1.09–1.83)). Combined blunted HRR1 and HRR2 or HR response and HRR1 further increased risk of all-cause (1.92 (1.64–2.24) and 1.85 (1.55–2.22), respectively) and CV mortality (1.95 (1.50–2.54) and 1.94 (1.42–2.65), respectively). HR recovery variables (HRR1, 1.97 (1.63–2.39) and HRR2, 1.76 (1.46–2.12)) remained stronger predictors of mortality than peak HR (1.38 (1.10–1.72)) in individuals with normal exercise capacity. Conclusions All HR variables were age-dependent and associated with mortality. Blunted HR recovery was more strongly related to mortality than chronotropic incompetence, and their combination added prognostic value. Furthermore, blunted HR recovery variables, rather than blunted HR response, remained strongly associated with mortality even in the presence of normal exercise capacity.

Heart rate response and recovery in cycle exercise testing - normal values and association with mortality.

Chronotropic incompetence and impaired heart rate (HR) recovery are related to mortality. Guidelines lack specific reference values for HR recovery. We defined normal values and studied blunted HR response and recovery, and mortality risk. We included 9,917 subjects (45% females) aged 18-85 years who performed a cycle exercise test. We defined normal values for peak HR, HR reserve, and HR recovery at 1 and 2 minutes (HRR1 and HRR2) based on individuals apparently healthy (N=2,242). Associations between blunted HR indices (<5th percentile) and mortality over a median follow-up of 8.6 years were analysed using Cox regression and competing risk analysis. All HR indices were age-dependent and independent predictors of all-cause and CV mortality. The 5th percentiles of HR reserve, HRR1, and HRR2 correlated weakly with existing reference values. HR recovery variables were the strongest predictors of all-cause mortality (HRR1, hazard ratio 1.70 [95% confidence interval, 1.49-1.94] and HRR2, 1.57 [1.37-1.79]), including in subjects with normal exercise capacity (HRR1, 1.96 [1.61-2.39] and HRR2, 1.76 [1.46-2.12]). Combining HR indices appeared to increase the risk of all-cause (HRR1 and HRR2, 1.96 [1.68-2.29] and peak HR and HRR1, 1.87 [1.56-2.23]) and CV mortality, although no specific combination was superior for predicting CV mortality. All HR variables were age-dependent and associated with all-cause and CV mortality. Blunted HR recovery variables were the strongest predictors of all-cause mortality, even in subjects with normal exercise capacity. Combined blunted HR indices appeared to add prognostic value.

Workloads in Collegiate Women's Lacrosse Athletes During a Division II National Championship Season.

Sutton, PJ, Mumford, PW, and Sunderland, KL. Workloads in collegiate women's lacrosse athletes during a Division II national championship season. J Strength Cond Res 38(9): 1651-1657, 2024-A comprehensive examination of the external and internal workloads in collegiate women's lacrosse athletes has yet to be reported. Thus, the primary purpose of this study was to determine the absolute and relative external and internal training and game workloads of National Collegiate Athletic Association (NCAA) Division II women's lacrosse athletes throughout an entire season. Data from 19 Division II women's lacrosse athletes were analyzed, encompassing each training session and game across an entire competitive season (February-May). External workloads were assessed using a wearable global positioning system, whereas internal workloads were determined through heart rate (HR) variables and session rating of perceived exertion. Game days were associated with significantly ( p < 0.05) greater absolute external and internal workloads. However, when comparing workloads relative to session duration, relative workloads between training and games were no longer significant ( p > 0.05) for total distance, high-speed running (≥15 km·h -1 ), HR-derived training impulse, or caloric expenditure. Nonetheless, relative sprint distance (>19 km·h -1 ) was significantly lower during games, whereas high-intensity accelerations (>2 m·s -2 ) and decelerations (<-2 m·s -2 ) were significantly greater during training compared with games ( p < 0.05). Practical applications of these findings suggest that coaches can better prepare athletes for game day conditions by adjusting training plans to replicate the duration and intensity of games. Overall, this comprehensive examination of internal and external workloads provides valuable data for coaches and practitioners to support performance comparisons, rehabilitation protocols, and workload analyses in collegiate women's lacrosse athletes.

Ultrasound-guided lesser occipital nerve combined with great auricular nerve block for vestibular schwannoma craniotomy via a suboccipital retrosigmoid approach: a prospective, double-blind randomized controlled trial

PurposeThis aim of this study was to investigate the analgesic efficacy and safety of lesser occipital nerve combined with great auricular nerve block (LOGAB) for craniotomy via a suboccipital retrosigmoid approach.MethodsPatients underwent vestibular schwannoma resection via a suboccipital retrosigmoid approach were randomly assigned to receive ultrasound-guided unilateral LOGAB with 5 ml of 0.5% ropivacaine (LOGAB group) or normal saline (NSB group). Numeric rating scale (NRS) scores at rest and motion were recorded within 48 h after surgery. Mean arterial pressure (MAP), heart rate (HR), opioid consumption and other variables were measured secondly.ResultsAmong 59 patients who were randomized, 30 patients received ropivacaine, and 29 patients received saline. NRS scores at rest (1.8 ± 0.5 vs. 3.2 ± 0.8, P = 0.002) and at motion (2.2 ± 0.7 vs. 3.2 ± 0.6, P = 0.013) of LOGAB group were lower than those of NSB group within 48 h after surgery. NRS scores of motion were comparable except for 6th and 12th hour (P < 0.05) in the LOGAB group. In LOGAB group, MAP decreased significantly during incision of skin and dura (P < 0.05) and intraoperative opoid consumption was remarkably reduced (P < 0.01). Postoperative remedial analgesia was earlier in the NSB group (P < 0.001). No patients reported any adverse events.ConclusionAmong patients undergoing craniotomy for vestibular schwannoma via a suboccipital retrosigmoid approach, LOGAB may be a promising treatment for perioperative analgesia and has the potential to maintain intraoperative hemodynamic stability.Clinical trial registration numberChictr.org.cn ChiCTR2000038798.

Effects of Altitude training on Ethiopian endurance athletes recovery heart rate and hematological variables

Background and Study Aim. A recent study indicates that Ethiopian middle- and long-distance athletes originate from diverse geographical regions, including areas of varying elevation. This study aimed to analyze the impact of altitude training on hematological parameters and recovery heart rates among young male endurance trainees training at sites located at different altitude levels. Material and Methods. The study employed a quasi-experimental, counterbalanced approach involving 15 male trainees. Five individuals from each training center experienced the standard training program across three distinct geographical locations and elevations. Pre- and post-test data were collected on red blood cells, hemoglobin, hematocrit, platelet count, and recovery heart rate before and after six months, from 6:00–8:00 AM. ANCOVA was utilized to analyze the data. Results. Following the intervention, the mean Red Blood Cell (RBC) count was observed to be higher in trainees from low altitude (5.18±0.33) compared to those from moderate altitude (4.48±0.14 and 5.21±0.22), with a significance level of p&lt;0.05. The mean Hemoglobin (HGB) count was found to be higher in moderate altitude trainees (17.00±0.70 and 16.31±0.65) than in low altitude trainees (15.82±1.37), although this difference was not statistically significant (p&gt;0.05). Similarly, the mean Hematocrit (HCT) count was low for both low altitude (46.04±3.49) and moderate altitude trainees (46.46±3.9 and 45.42±1.54), with no significant difference noted (p&gt;0.05). The mean Platelet (PLT) count was 226.8±75.88 for low altitude trainees and 265.8±23.18, 276±53.96 for moderate altitude trainees, with no significant difference between the groups (p&gt;0.05). As for the recovery heart rate, mean values showed no significant difference between the pre-and post-test groups. In the pretest, the mean recovery heart rate was 30.00±14.70 for low-altitude trainees and 43.20±8.90, 43.20±13.68 for moderate-altitude trainees (p&gt;0.05). In the post-test, the mean recovery heart rate was 25.20±7.82 for low-altitude trainees and 32.40±10.04, 36.00±7.35 for moderate-altitude trainees (p&gt;0.05). Conclusions. The findings indicate that training at different altitudes impacts the hematological and cardiovascular systems of endurance athletes in varied ways. This underscores the importance of developing tailored training programs to optimize performance and recovery. These results are particularly relevant for coaches and athletes seeking to enhance endurance training outcomes through altitude training strategies.

Effects of the increase of longitudinal bending stiffness of advanced footwear technology on 3,000m performance, pacing strategy, and biomechanics

This study aimed to analyse the effects of shoes with increased longitudinal bending stiffness (LBS) on 3,000 m performance, pacing strategy, heart rate, and biomechanics in trained runners. Twelve male trained runners performed a 3,000 m time trial test in an experimental shoe with a carbon fibre plate to increase the LBS (LBS-increased) and a Control shoe (without carbon fibre plate). Running performance (total time), pacing, heart rate, and biomechanical variables were registered and analysed for each 1000 m split. An individual analysis of the responders was performed based on the smallest worthwhile change. The 3,000 m time trial performance improved by 0.74% (585.83 ± 33.39 vs. 590.17 ± 34.35 s, p < 0.001, large d = 0.829) in the LBS-increased condition compared to the Control condition with a high inter-individual variability. There were no significant differences for the split effect (p = 0.898, small ηp2 = 0.021). The performance improvement was accompanied by an increase in step length (p < 0.001, large ηp2 = 0.717) throughout the time trial test and an increase of flight time in the split 1 and 2 (p < 0.05, moderate d = 0.793, 0.686, respectively) and vertical oscillation in the split 2 and 3 (p < 0.05, moderate d = 0.727, 0.652). However, the heart rate remained unchanged between conditions. The increase of LBS in footwear can improve 3,000 m performance without causing changes in the pacing strategy. Small modifications in running kinematics accompanied the improvements in running performance but without changes in heart rate. Moreover, LBS-increased did not affect all runners equally highlighting the need for further understanding of individual responses.

The reliability and discriminant validity of physical, technical, and perceptual-physiological measures during a game-specific basketball activity simulation protocol.

Activity simulation protocols offer useful applications in research and practice; however, the specificity of such protocols to basketball game-play is currently lacking. Consequently, this study aimed to develop a game-specific basketball activity simulation protocol representative of typical playing durations and assess its reliability and discriminant validity. The simulation protocol was modified from an original version (i.e., Basketball Exercise Simulation Test) to incorporate regular breaks indicative of time-outs, free-throws, and substitutions. Twelve competitive male and female adult basketball players competing in the fourth or fifth Spanish basketball division underwent repeated trials of the simulation protocol (min. 4 to max. 14 days apart) for reliability analyses. In turn, 13 competitive male (fifth division), 9 competitive female (fourth division), and 13 recreational male adult basketball players completed the simulation protocol to assess discriminant validity via comparisons between sexes (competitive players) and playing levels (males). A range of physical, technical, and perceptual-physiological variables were collected during and following the simulation protocol. Several physical and heart rate variables displayed the strongest reliability (intraclass correlation coefficient [ICC] = 0.72-0.96; coefficient of variation [CV] = 1.78-6.75%), with physical decrement, technical, blood lactate concentration, and rating of perceived exertion (RPE) variables having the weakest (ICC = 0.52-0.75; CV = 10.34-30.85%). Regarding discriminant analyses between sexes, males demonstrated significantly greater physical outputs in several variables and lower RPE compared to females (p < 0.05, moderate-to-large effects). Comparisons between playing levels revealed competitive males had significantly greater physical outputs across many variables, alongside higher mean heart rate and lower RPE than recreational males (p < 0.05, moderate-to-large effects). This study presents a novel game-specific basketball activity simulation protocol replicating actual playing durations and game configurations that might be successfully applied for both training and research purposes. Reliability statistics are provided for several variables to inform end-users on potential measurement error when implementing the simulation protocol. Discriminant validity of the simulation protocol was supported for several variables, suggesting it may hold practical utility in benchmarking or selecting players. Future research on this topic is encouraged examining wider samples of male and female basketball players at different levels as well as additional forms of validity for the protocol.

Longitudinal analysis of echocardiographic and cardiac biomarker variables in dogs with atrial fibrillation: The optimal rate control in dogs with atrial fibrillation II study.

Rate control (RC; meanHRHolter ≤ 125 bpm) increases survival in dogs with atrial fibrillation (AF). The mechanisms remain unclear. Investigate echocardiographic and biomarker differences between RC and non-RC (NRC) dogs. Determine if changes post-anti-arrhythmic drugs (AAD) predict successful RC in subsequent Holter monitoring. Evaluate if early vs late RC affects survival. Fifty-two dogs with AF. Holter-derived mean heart rate, echocardiographic and biomarker variables from dogs receiving AAD were analyzed prospectively at each re-evaluation and grouped into RC or NRC. The primary endpoint was successful RC. Between group comparisons of absolute values, magnitude of change from admission to re-evaluations and end of study were performed using Mann-Whitney tests or unpaired t-tests. Logistic regression explored variables associated with inability to achieve RC at subsequent visits. Kaplan-Meier survival analysis was used to compare survival time of early vs late RC. At visit 2, 11/52 dogs were RC; at visit 3, 14/52 were RC; and at visit 4, 4/52 were RC. At the end of study, 25/52 remained NRC. At visit 2, both groups had increased cardiac dimensions, but NRC dogs had larger dimensions; biomarkers did not differ. At the end of study, RC showed decreased cardiac dimensions and end-terminal pro-brain natriuretic peptide (NT-proBNP) compared with NRC. No variables were useful at predicting RC success in subsequent visits. Survival analysis found no differences between early vs late RC. The RC dogs had decreased cardiac dimensions and NT-proBNP, suggesting HR-mediated reverse-remodeling might benefit survival, even with delayed RC achievement. Pursuit of RC is crucial despite initial failures.

Cardiohemodynamic responses and heart rate variability following an active orthostatic test among male residents of the North with different NOS3 (rs2070744) genotypes

AIM: This study explored associations between the -786TC (rs2070744) genetic polymorphism of the NOS3 gene and the main indices of systemic hemodynamics and heart rate variability following an active orthostatic test in men living in the North. MATERIAL AND METHODS: Eighty-three healthy men aged 33.5±1.5 yеаrs on average, who were permanent residents of the Magadan Region, comprised the sample. The participants underwent both resting and active orthostatic testing modes. Cardiovascular system variables were recorded using an automatic tonometer. Hemodynamic indices were then calculated. Short-term heart rate variability in frequency and spectral areas was simultaneously measured using the Varikard hardsoft complex unit. Genotyping was conducted using polymerase chain reaction. The sample was then divided into two groups: Group 1 consisted of homozygotes with the TT genotype (n=34), while Group 2 comprised carriers of the NOS3*C allele variant (genotypes TC+CC) associated with reduced nitric oxide production (n=49). RESULTS: By examining the complex vasomotor, chrono- and inotropic reactions of hemodynamic and heart rate variables during the active orthostatic test, we were able to discern unique patterns in the response of the two groups under study. Men in Group 1 demonstrated an elevated cardiac output response during orthostatic changes, while maintaining consistent vascular resistance values. This was accompanied by a shift towards sympathetic autonomic activity and an increase in the very low-frequency component of heart rate variability. In Group 2, individuals with sympathetic insufficiency and increased vascular resistance during the orthostatic test showed a 35% increase in the low-frequency component of the cardiac rhythm reflecting the importance of this indicator as a stimulator of blood pressure rhythm fluctuations mediated by baroreflex mechanisms. CONCLUSION: Our findings suggest that men lacking the NOS3*С allele variant in their genotype demonstrate more favorable responses to the active orthostatic test. This may reflect higher level of cardiovascular functional reserves. The 786TC (rs2070744) polymorphism of the NOS3 gene can be considered as a marker of cardiohemodynamic status and autonomic regulations during functional exercise, such as an active orthostatic test.

Re-evaluating the Need for Routine Maximal Aerobic Capacity Testing within Fighter Pilots.

INTRODUCTION: There is a current belief in aviation suggesting that aerobic training may reduce G-tolerance due to potential negative impacts on arterial pressure response. Studies indicate that increasing maximal aerobic capacity (<mml:math id="ie1" display="inline"><mml:mrow><mml:mover><mml:mtext>V</mml:mtext><mml:mo>˙</mml:mo></mml:mover></mml:mrow></mml:math>o₂ max) through aerobic training does not hinder G-tolerance. Moreover, sustained centrifuge training programs revealed no instances where excessive aerobic exercise compromised a trainee's ability to complete target profiles. The purpose of this review article is to examine the current research in the hope of establishing the need for routine <mml:math id="ie2" display="inline"><mml:mrow><mml:mover><mml:mtext>V</mml:mtext><mml:mo>˙</mml:mo></mml:mover></mml:mrow></mml:math>o₂-max testing in air force pilot protocols.METHODS: A systematic search of electronic databases including Google Scholar, PubMed, the Aerospace Medical Association, and Military Medicine was conducted. Keywords related to "human performance," "Air Force fighter pilots," "aerobic function," and "maximal aerobic capacity" were used in various combinations. Articles addressing exercise physiology, G-tolerance, physical training, and fighter pilot maneuvers related to human performance were considered. No primary data collection involving human subjects was conducted; therefore, ethical approval was not required.RESULTS: The <mml:math id="ie3" display="inline"><mml:mrow><mml:mover><mml:mtext>V</mml:mtext><mml:mo>˙</mml:mo></mml:mover></mml:mrow></mml:math>o₂-max test provides essential information regarding a pilot's ability to handle increased Gz-load. It assists in predicting G-induced loss of consciousness by assessing anti-G straining maneuver performance and heart rate variables during increased G-load.DISCUSSION: <mml:math id="ie4" display="inline"><mml:mrow><mml:mover><mml:mtext>V</mml:mtext><mml:mo>˙</mml:mo></mml:mover></mml:mrow></mml:math>o₂-max testing guides tailored exercise plans, optimizes cardiovascular health, and disproves the notion that aerobic training hampers G-tolerance. Its inclusion in air force protocols could boost readiness, reduce health risks, and refine training for fighter pilots' safety and performance. This evidence-backed approach supports integrating <mml:math id="ie5" display="inline"><mml:mrow><mml:mover><mml:mtext>V</mml:mtext><mml:mo>˙</mml:mo></mml:mover></mml:mrow></mml:math>o₂-max testing for insights into fitness, risks, and tailored exercise.Zeigler Z, Acevedo AM. Re-evaluating the need for routine maximal aerobic capacity testing within fighter pilots. Aerosp Med Hum Perform. 2024; 95(5):273-277.

Constructing an elderly health monitoring system using fuzzy rules and Internet of Things

Monitoring the health of the elderly using wearable sensors and Internet of Things (IoT) devices necessitates the collection of data from various sources, thereby increasing the volume of data to be gathered at the monitoring center. As previously elucidated, the system exhibits high accuracy in measuring variables such as blood oxygen saturation (BOS) and heart rate (HR), as well as demonstrating proficient accuracy in implementing fuzzy rules to detect the “stable” or “unstable” condition of elderly patients. Therefore, by integrating wearable sensors and IoT devices into the elderly health monitoring system, we can enhance the quality of monitoring and provide more timely healthcare solutions tailored to the elderly population’s needs. The integration of fuzzy rules and IoT technology into the elderly health monitoring system offers an efficient and effective solution for continuous health surveillance. In this research, we integrated fuzzy rules and IoT technology into the elderly health monitoring system using parameters such as BOS and HR, through the integration of MAX30100 sensors and ESP32 microprocessors. The implementation of fuzzy rules resulted in nine rules indicating whether an elderly patient is in a “stable” or “unstable” condition. The methodology involved (1) component preparation, (2) device accuracy analysis, (3) fuzzy rule development, (4) Android-based mobile application development, (5) fuzzy rule accuracy analysis, and (6) cost analysis. Experimental results indicated a device accuracy of 98.89% in measuring BOS and HR variables compared to medical devices and a fuzzy rule accuracy of 96% in detecting whether the patient’s condition is “stable” or “unstable.” Based on the experimental findings, the elderly health monitoring system provides a user-friendly, precise, and cost-effective solution to enhance the quality of life for the elderly population.

Calculating Load and Intensity Using Muscle Oxygen Saturation Data.

The study aimed to calculate training intensity and load using muscle oxygen saturation (SmO2) during two differentiated physical tasks. 29 university athletes participated in a 40-m Maximal Shuttle Run Test (MST, 10 × 40-m with 30 s recovery between sprints) and a 3000-m time trial run. Distance and time were used to calculate external load (EL). Internal load indicators were calculated based on percentage of maximum heart rate (%HRMAX) and SmO2 variables: muscle oxygen extraction (∇%SmO2) and the cardio-muscle oxygen index (CMOI) was also provided by relating ∇%SmO2 ÷ %HRMAX, and the training load were calculated as the product of speed (m/min × IL) and the efficiency index [Effindex (m/min ÷ IL)]. A student t test was applied based on Bayesian factor analysis. As expected, EL differed in the 40-m MST (331 ± 22.8) vs. 3000-m trials (222 ± 56.8) [BF10 = 6.25e+6; p = <0.001]. Likewise, IL showed higher values in 40-m MST (39.20 ± 15.44) vs. 3000-m (30.51 ± 8.67) in CMOI: [BF10 = 1.70; p = 0.039]. Training load was greater in 40-m MST (85.77 ± 27.40) vs. 3000-m (15.55 ± 6.77) [(m/min × ∇%SmO2): BF10 = 12.5; p = 0.003] and 40-m MST (129.27 ± 49.44) vs. 3000-m (70.63 ± 32.98) [(m/min × CMOI): BF10 = 169.6; p = <0.001]. Also, the Effindex was higher in 40-m MST (10.19 ± 4.17) vs. 3000-m (6.06 ± 2.21) [(m/min × ∇%SmO2): BF10 = 137.03; p = <0.001] and 40-m MST (9.69 ± 4.11) vs. 3000-m (7.55 ± 1.87) [(m/min × CMOI): BF10 = 1.86; p = 0.035]. This study demonstrates calculations of training intensity and load based on SmO2 as an internal load indicator along with speed as an external load indicator during two differentiated exercises.

Validation of Air Storage System for Hypoxia Exposure During Exercise.

Norberto, Matheus S., João Victor G. Torini, Matheus S. Firmino, and Marcelo Papoti. Validation of air storage system for hypoxia exposure during exercise. High Alt Med Biol. 00:000-000, 2024.-Considering the importance of optimizing normobaric hypoxia exposure (i.e., higher delivery capacity), the current study aims to validate a hypoxic air storage system. The study has a cross-over, one-blind randomized design. The air storage is composed of a piping system that directs hypoxic air from a hypoxia generator into nylon bags. Sixteen men (age, 25.4 ± 4.8 years; height, 174.9 ± 9.4 cm; weight, 77.1 ± 17.2 kg) performed three incremental treadmill tests until exhaustion on different days. For test-retest, the subjects repeated two tests in similar hypoxia conditions (H1 and H2; fraction of inspired O2 [FIO2] = ∼0.13; reliability analysis), and one time in normoxia (FIO2 = ∼0.20; condition comparison). Subjects' performance, blood lactate concentration ([La-]), arterial oxygen saturation (SpO2), oxygen consumption (VO2), heart rate (HR), and several respiratory-derived variables were evaluated. A comparison was made between the rest, moderate intensity, and exhaustion stages. All variables were compared using the Friedman test with Durbin-Conover post hoc (p < 0.05). The hypoxia test-retest showed no statistical differences for any variable. Time analysis showed similar behavior for SpO2, HR, and cardiorespiratory variables (p < 0.01) for both conditions. The mean FIO2 at rest and during the incremental treadmill test was higher for normoxia (20.6 ± 0.2%) than for H1 (13.8 ± 0.8%) and H2 (13.7 ± 0.3%) (p < 0.001). The VO2 response was higher in normoxia than during hypoxia exposure at moderate intensity (Normoxia = 43.1 ± 8.1; H1 = 38.7 ± 5.7; H2 = 35.8 ± 8.8 ml.kg-1.min-1) and at the exhaustion stage (Normoxia = 52.7 ± 12.5; H1 = 41.9 ± 8.8; H2 = 40.5 ± 8.9 ml.kg-1.min-1) (p < 0.01). SpO2 and HR showed excellent intraclass correlation coefficient (ICC) during all moments, whereas VO2, SpO2, ratio between ventilation and CO2 production (VE/VCO2), ratio between oxygen consumption and ventilation (VE/VO2), and HR showed moderate or good ICC and coefficient of variation <9% during hypoxia test-retest exercises. Thus, the air storage system showed validity for its application and reliability in the measurements associated.

Evaluation of physical variables, thermal nociceptive threshold testing and pharmacokinetics during placement of transdermal buprenorphine matrix-type patch in healthy adult horses.

Matrix type transdermal buprenorphine patches have not been investigated in horses and may provide an effective means of providing continuous pain control for extended period and eliminating venous catheterization. Assessment of the physiological variables (heart rate, respiratory rate, body temperature) and thermal nociceptive threshold testing, and describing the pharmacokinetic profile of transdermal buprenorphine matrix-type patch (20 μg h-1 and 40 μg h-1 dosing) in healthy adult horses. Randomised experimental study with a Latin-square design. Six adult healthy horses received each of the three treatments with a minimum 10 day washout period. BUP0 horses did not receive a patch (control). BUP20 horses received one patch (20 μg h-1) applied on the ventral aspect of the tail base resulting in a dose of 0.03-0.04 μg kg-1 h-1. BUP40 horses received two patches placed alongside each other (40 μg h-1) on the tail base resulting in a dose of 0.07-0.09 μg kg-1 h-1. Whole blood samples (for determination of buprenorphine concentration), physiological variables and thermal threshold testing were performed before (0 h) and at 2, 4, 8, 12, 16, 24, 32, 40, 48, 56, 64, 72, and 96 h after patch application. The patches were removed 72 h following placement and were analyzed for residual buprenorphine content. Between the three groups, there was no change in physiological variables across timepoints as compared to baseline (p > 0.1). With the higher dose, there was a significant increase in thermal thresholds from baseline values from 2 h until 48 h and these values were significantly higher than the group receiving the lower patch dose for multiple timepoints up to 40 h. 40 μg h-1 patch led to consistent measurable plasma concentrations starting at 2 h up to 96 h, with the mean plasma concentrations of > 0.1 ng/ml from 4 h to 40 h. 20 μg h-1 and 40 μg h-1 patch doses were well tolerated by all horses. At higher dose, plasma buprenorphine concentrations were more consistently measurable and blunted thermal thresholds for 48 h vs. 32 h with 20 μg h-1 dosing as compared to control.

Effects of shift work on sleep quality and cardiovascular function in Taiwanese police officers

ABSTRACT This study aimed to investigate the effects of shift work on sleep quality, cardiovascular function, and physical activity (PA) levels in Taiwanese police officers. Twenty-one male police officers aged 26.9 ± 4.1 years old located in Taipei voluntarily participated in this study. The participants completed the resting heart rate (HR) and hemodynamic variables (e.g. blood pressure, BP) before and after day-time (DTW) and night-time (NTW) shift work phases (5 working days and 2 resting days for each phase). Additionally, an actigraphy was administered to measure PA and sleep patterns in the last 3 working days. The average total sleep time and sleep efficiency were 278.5 ± 79. 6 min and 72.9 ± 10%, respectively, in the NTW phases, which were significantly lower than that in the DTW phases. A comparison of the PA characteristics between the two phases revealed that a lower proportion of moderate-vigorous PA (1.2 ± 0.8%) and a greater proportion of sedentary behaviour PA (74.8 ± 6.4%) was found in the NTW phases. The results of hemodynamic measures demonstrated that the police officers have significantly elevated systolic BP by 3.3% and diastolic BP by 3.9% after the NTW phases. Furthermore, the NTW phases exhibited a significantly higher percentage change ratio of systolic BP and diastolic BP compared to the DTW phases. Compared with the DTW phases, the NTW phase was significantly more likely to report higher decreasing parasympathetic-related HR variability with a range of −5.9% to −7.8%. In conclusion, night-time shift work resulted in negative physiological changes leading to adverse effects on the health and well-being of Taiwanese police officers.

Belief That Caffeine Ingestion Improves Performance in a 6-Minute Time Trial Test without Affecting Pacing Strategy.

Thirteen recreationally trained males in long-distance running (age: 38.5 ± 11.9 years, 11.0 ± 8.8 years of running experience) performed a 6 min time trial test in each experimental condition (caffeine-informed/placebo ingested (placebo) and non-ingested (control)) separated by 7 days. The total distance covered was measured, and partial times of each 400 m were used to analyze the pacing strategy. Heart rate and kinematic variables were recorded for each split. In addition, the rate of perceived exertion and prevalence of caffeine side effects was measured using questionnaires. Placebo ingestion improved running performance in the 6 min time trial test (1668 ± 139 m placebo vs. 1642 ± 158 m control, t = 2.49; p = 0.03; moderate ES = 0.69), while pacing, heart rate, RPE, and kinematic variables were similar between conditions (p > 0.05 in all cases). Minor side effects were reported. Beliefs of caffeine ingestion can improve running performance at speeds around maximal aerobic speed in recreationally trained runners without affecting pacing strategy so this "nutritional" strategy could be useful in competition scenarios. As a practical application, recreationally trained runners could improve ≈5 s in 1500 m or mile competitions.

Assessing the Risk of Hypertension in Chronic, Elderly Patients during the COVID-19 Pandemic: A Prospective Study.

This study considers care management for older chronic patients during and after the COVID-19 pandemic. To identify groups of variables at previous time points as a basis for deriving efficient classification models during and after a pandemic situation and to quantify the effect of each variable within the model to predict levels of worsening risk in diastolic and systolic arterial hypertension (AHT). In this prospective longitudinal study, data were collected at three time points: before, during, and after the COVID-19 pandemic period. The study included 148 patients with an average age of 81.6 years. During the study period, mean systolic blood pressure among this population rose by 5 mmHg to 128.8 mmHg; the number of patients with systolic blood pressure > 140 mmHg rose by 45.3%; among those with diastolic blood pressure > 90, the number rose by 41.2%; mean triglycerides levels rose to 152.6 mg/dL; cholesterol levels rose to 147 mg/dL; and LDL cholesterol rose to 112.2 mg/dL. Meanwhile, mean levels of HDL cholesterol decreased to 46.5 mg/dL. Binary-response logistic regression models were constructed to identify the most relevant variables for predicting AHT risk during and after the pandemic. The heart rate (OR = 1.79; 95% CI: 1.22-2.72) and body mass index (OR = 1.75; 95% CI: 1.08-2.94) variables were significant at the population level (p < 0.05) for diastolic and systolic AHT in the pandemic period risk models. The body mass index variable was also significant for diastolic AHT in the post-pandemic period risk model (OR = 1.97; 95% CI: 1.32-2.94), whilst the triglycerides variable was significant in the systolic AHT post-pandemic period risk model (OR = 1.49; 95% CI: 1.01-1.86). Bad control of arterial hypertension in older patients with chronic disease is associated with elevated levels of LDL cholesterol, total cholesterol, systolic blood pressure, heart rate and triglycerides, and lower levels of HDL cholesterol.

ANESTHESIA IN CAPTIVE GIANT PANDAS (AILUROPODA MELANOLEUCA) WITH MEDETOMIDINE-KETAMINE.

One male and one female giant panda (Ailuropoda melanoleuca) from a Belgian zoo were anesthetized on eight different occasions over a course of 4 yr for electro-ejaculation (n = 3) or artificial insemination (n = 5). Medetomidine (0.03-0.04 mg/kg) and ketamine (2.5-3 mg/kg) were administered by intramuscular remote injection. Animals gained sternal recumbency with the loss of response to external stimuli after 4.9 ± 1.6 min (mean ± SD). The trachea was intubated with a 14-mm-internal diameter endotracheal tube; anesthesia was maintained with isoflurane in oxygen adjusted according to the required depth of anesthesia with a small-animal circle system. Physiological variables (heart rate, respiratory rate, oxygenation, end tidal carbon dioxide partial pressure and non-invasive blood pressure) were measured and remained within an acceptable range throughout anesthesia. Atipamezole (0.17-0.25 mg/kg) was administered intramuscularly after anesthesia. Recoveries were rapid and uneventful. Medetomidine 0.03 mg/kg and ketamine 2.5 mg/kg IM appeared to be the preferred doses for giant pandas.