Peak Heart Rate Research Articles

Central and peripheral haemodynamics at exercise onset: the role of central command

PurposeThe involvement of central command in central hemodynamic regulation during exercise is relatively well-known, although its contribution to peripheral hemodynamics at the onset of low-intensity contractions is debated. This study sought to examine central and peripheral hemodynamics during electrically-evoked muscle contractions (without central command) and voluntary muscle activity (with central command).MethodsCyclic quadriceps isometric contractions (1 every second), either electrically-evoked (ES; 200 ms trains composed of 20 square waves) or performed voluntarily (VC), were executed by 10 healthy males (26 ± 3 years). In both trials, matched for force output, peripheral and central hemodynamics were analysed.ResultsAt exercise onset, both ES and VC exhibited equal peaks of femoral blood flow (1276 ± 849 vs. 1117 ± 632 ml/min, p > 0.05) and vascular conductance (15 ± 11 vs. 13 ± 7 ml/min/mmHg, p > 0.05), respectively. Similar peaks of heart rate (86 ± 16 bpm vs. 85 ± 16 bpm), stroke volume (100 ± 20 vs. 99 ± 27 ml), cardiac output (8.2 ± 2.5 vs. 8.5 ± 2.1 L/min), and mean arterial pressure (113 ± 13 vs. 113 ± 3 mmHg), were recorded (all, p > 0.05). After ~ 50 s, all the variables drifted to lower values. Collectively, the hemodynamics showed equal responses.ConclusionThese results suggest a similar pathway for the initial (first 40 s) increase in central and peripheral hemodynamics. The parallel responses may suggest an initial minimal central command involvement during the onset of low-intensity contractions, likely associated with a neural drive activation delay or threshold.

Higher final speed in 30–15 intermittent fitness tests correlates with soccer's locomotor demands, not heart rate responses in small-sided soccer games

This study aimed to achieve two objectives: firstly, to analyze the relationships between aerobic fitness, as represented by the VIFT, and the heart rate and locomotor responses of youth male soccer players across various teams; and secondly, to compare players with lower and higher VIFT in terms of performance outcomes extracted during small-sided games (SSGs). A total of twenty-six youth male soccer players, aged 16.5 ± 0.32 years, with 3.4 ± 1.1 years of experience, voluntarily participated in the study. These players belonged to two regional-level tier 2 teams (trained/developmental). In the initial week of observation, the 30–15 Intermittent Fitness Test was implemented to measure the final velocity (VIFT) achieved by the players. Subsequently, the 5v5 format of play was conducted twice a week over two consecutive weeks, during which heart rate responses and locomotor demands were measured. The Pearson product-moment correlation test revealed a significant correlation between VIFT and the total distance covered during the 5v5 format (r = 0.471 [95% CI: 0.093; 0.721], p = 0.015). Conversely, small and non-significant correlations were identified between VIFT and mean heart rate (r = 0.280 [95% CI: − 0.126; 0.598]; p = 0.166), VIFT and peak heart rate (r = 0.237 [95% CI: − 0.170; 0.569]; p = 0.243), as well as VIFT and high-speed running (r = 0.254 [95% CI: − 0.153; 0.580]; p = 0.211). Players with higher VIFT demonstrated a significantly greater total distance, with a large effect size (+ 6.64%; p = 0.015; d = 1.033), compared to those with lower VIFT. Our findings suggest that improved performance in VIFT may lead to covering more distance in 5v5 matches. However, the lack of significant associations between VIFT and heart rate levels during SSGs suggests that they are not strongly correlated, possibly because VIFT is more closely linked to locomotor profile. As a practical implication, coaches may consider organizing players during SSGs based on their VIFT if the goal is to standardize locomotor demands.

Role of ASIC3 in Evoking the Exercise Pressor Reflex in Type 1 Diabetes Mellitus Rats

Previous studies have suggested that the exercise pressor reflex is exaggerated in individuals with type 1 diabetes mellitus (T1DM); however, the mechanisms responsible for this altered reflex are poorly understood. Acid-sensing ion channel 3 (ASIC3) likely contributes to this exaggeration as previous studies found that peripheral blockade, as well as functional knockout (KO) of the ASIC3 gene, prevented the exaggeration of exercise pressor reflex in rats with cardiovascular-related diseases. However, whether ASIC3 plays a similar role in the exaggerated exercise pressor reflex in T1DM is currently unknown. Therefore, the purpose of this study was to determine whether ASIC3 contributes to the exaggerated exercise pressor reflex in T1DM rats. We hypothesized that the exaggerated exercise pressor reflex would be attenuated in ASIC3 KO T1DM rats compared to their wild-type (WT) counterparts. To test this, we used adult, male and female Wistar-Kyoto ASIC3 KO (n=3; body weight: 348 ± 84 g) and WT counterparts (n=5; body weight: 318 ± 112 g) rats. Streptozotocin (50 mg/kg) was injected intraperitoneally in fasted anesthetized rats to induce T1DM, and a random blood glucose over 300 mg/dl was used to diagnose diabetes. One week later, the exercise pressor reflex was evoked in unanesthetized, decerebrated rats by statically contracting the hindlimb muscles for 30 s. Peak mean arterial pressure (MAP) and heart rate (HR) were calculated as the highest change (Δ) during 30 s contraction baseline. We found that the peak pressor and cardioaccelerator responses to static contraction, although is not statistically significant, appear to be lower in ASIC3 KO (ΔMAP: 17 ± 14 mmHg; ΔHR: 13 ± 12 bpm), compared to WT rats (ΔMAP: 23 ± 11 mmHg; P=0.26 ΔHR:23 ± 9 bpm; P=0.11). Furthermore, we found that within female rats, the peak pressor and heart rate responses were lower in ASIC3 KO (n=1) rat (ΔMAP: 7 mmHg; ΔHR: 15 bpm) compared to WT rats (n=3) (ΔMAP: 27 ± 12 mmHg; ΔHR: 27 ± 11 bpm). Our preliminary findings suggest that ASIC3 may play a role in the exaggerated exercise pressor reflex in T1DM rats and that sex differences may also be present. Further studies involving larger sample sizes will reveal if trends from the current results become significant. This project was supported by NIH R01HL 166323-01A1. 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.

Contributors to Diminished Cardiorespiratory Fitness in Young Users of Electronic Cigarettes

Background: Cardiorespiratory fitness, an independent marker of cardiovascular health, represents the ability of respiratory, cardiovascular, and muscular systems to effciently deliver and utilize oxygen (O2) during exercise. Recently, reduced cardiorespiratory fitness was identified in young and healthy, regular users of electronic (e-) cigarettes; however, its limiting factors are not established. Thus, the purpose of this study was to investigate the contributors to impaired cardiorespiratory fitness in young regular users of e-cigarettes. Methods: An evaluation of hemodynamics, chronotropic response, and oxygen utilization during exercise was completed in nineteen regular users of e-cigarettes (EU, age: 23±3 yr; e-cigarette usage 4±2 yr.) and sixteen demographically matched non-users (NU, age: 23±3 yr.). Hemodynamics were accessed via a non-invasive signal morphology impedance cardiography device, while chronotropic responses were measured as changes in peak heart rate (HR). Oxygen extraction ratio (difference in arterial and venous O2 content) at baseline and peak exercise was also recorded. Fold changes from rest to peak exercise were assessed to provide insight into potential factors that limit cardiorespiratory fitness. Results: At peak exercise, users of e-cigarettes exhibited significantly higher chronotropic incompetence ( p=0.033) and lower ( p=0.047) peak HR than non-users, with no differences in other hemodynamic assessments. Significantly ( p=0.025) lower skeletal muscle O2 extraction (EU=51±11 vs. NU=61±10%) was also observed in users of e-cigarettes during peak exercise. Fold changes in chronotropic (HR; p=0.915) and hemodynamic (cardiac output; p=0.279) responses were similar between both groups, while significant ( p=0.048) differences in oxygen extraction ratio were identified between the users of e-cigarettes (0.5±0.3 fold change) and non-users (0.8±0.3 fold change). Conclusions: Results from our study demonstrate that young, regular users of e-cigarettes exhibit abnormal chronotropic responses and impaired skeletal muscle oxygen utilization during exercise when compared to non-users, suggesting reduced cardiovascular and muscle health. Overall, our findings contribute to the growing body of evidence that supports the negative effects of regular e-cigarette use on young individuals. Supported in part by a Rapid Response Project NIDA/FDA (PRM). 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.

COMBINED HIGH-INTENSITY INTERVAL TRAINING FOR PEOPLE WITH DISORDERS OF GUT BRAIN INTERACTION: A CASE REPORT

AIMS The efficacy of high intensity exercise for improving symptoms of chronic idiopathic constipation, a highly prevalent disorder of gut brain interaction (DGBI), remains uncertain. The aim of this case report was to investigate the feasibility, safety, and efficacy of 8-weeks of combined high-intensity interval training (C-HIIT) for a person (female, 23 years old) with chronic constipation. METHODS The participant enrolled in the C-HIIT for DGBI controlled trial that aims to recruit 32 participants with DGBI. Following comprehensive assessments of gastrointestinal symptoms, neuromuscular fitness, cardiorespiratory fitness and mental health, the participant completed an 8-week intervention consisting of thrice weekly 26-minute C-HIIT sessions. These consisted of a 3-minute aerobic warm-up (treadmill; 50-60% peak heart rate [HRpeak]) followed by 4-minutes of high-intensity aerobic exercise at ≥85% HRpeak. After 1-minute rest, eight whole body resistance exercises were performed. These involved continuous repetitions with good technique for 1-minute at an ≥8/10 (very hard) rating of perceived exertion; 1-minute rest separated each exercise. Adverse events were recorded throughout the intervention. RESULTS The participant adhered to the intervention, attending 100% of sessions and reaching the prescribed intensity for 100% of aerobic and 80% of resistance exercises. Efficacy of the exercise training was indicated by a reduction in the severity of gastrointestinal symptoms measured via the irritable bowel syndrome-symptom severity scale (from 111 to 100) and the structured assessment of gastroIntestinal symptoms (39 to 12). There were some improvements in neuromuscular fitness (handgrip strength: 27 to 29.5 kg, 30-second sit to stands: 12 to 10 repetitions) and cardiorespiratory fitness (VO2max: 36.7 to 38.2 mL/kg/min). No changes were observed in mental health (Hospital Anxiety and Depression scale), and one non-serious adverse event (nausea post-eating), which was deemed not related to the intervention. CONCLUSION The C-HIIT intervention in a person with DGBI was feasible, efficacious and safe.

HIITING CANCER BACK: THE EFFECTS OF ONE MONTH OF HIGH INTENSITY INTERVAL TRAINING ON INFLAMMATION, BODY COMPOSITION, AND CARDIORESPIRATORY FITNESS IN CANCER SURVIVORS

INTRODUCTION/AIMS Chronic inflammation, low fitness, and unfavourable body composition are often side effects of anti-cancer therapies and are associated with an increased risk of cancer recurrence. However, the response of these variables to high intensity interval training (HIIT), and the relationship among these predictors of cancer recurrence, is yet to be explored in cancer survivors. The aim of this study was to investigate the effect of one month of HIIT on inflammation, body composition, and cardiorespiratory fitness and explore the relationships among these variables in breast, prostate, and colorectal cancer survivors. METHODS Survivors (n=131) of breast, prostate, and colorectal cancer (60.1±10.3 years, 26.9±4.9 kg/m2, 67% female) completed one month of HIIT (12 sessions: 4x4min at 85-95% peak heart rate (HRpeak), interspersed with 3-minutes at 50-75% HRpeak). Body composition via dual-energy X-ray absorptiometry, cardiorespiratory fitness via V̇O2peak, and fasted blood were measured at baseline and at one month. Blood was analysed for inflammatory factors (interleukin (IL)-6, IL-10), and tumour necrosis factor alpha (TNF-α)). RESULTS HIIT resulted in significant reductions in IL-6, IL-10, TNF-α (-37-39%, p<0.001) and significant increases in leg lean mass (+400g, p=0.008) and absolute V̇O2peak (+0.2 L/min, p<0.001). Despite this, the only significant association among the changes in these variables was a weak correlation between IL-10 and absolute V̇O2peak (rs=0.256, p=0.013). CONCLUSION One month of HIIT elicited significant improvement in markers of systemic inflammation, body composition, and cardiorespiratory fitness. However, improvements in these variables were not strongly related and occur independent of each other. The findings of this study demonstrate 4x4 HIIT is an effective prescriptive tool to elicit rapid improvements in physiological markers, through apparent independent pathways. Therefore, exercise physiologists working with cancer survivors should consider utilising 4x4 HIIT to their exercise prescriptions as a time efficient means to reduce the risk of cancer recurrence and improve survivorship.

High Intensity Interval Exercise Causes Acute Microvascular Dysfunction in Elderly Individuals with Low Cardiorespiratory Fitness - A Pilot Study

Background: Frailty is strongly associated with low physical and cardiorespiratory fitness, and unfortunately is observed in 20-50% of the ~50 million adults that experience surgical stress in the U.S. each year. The peripheral microvasculature may serve as a potential target to increase resilience to stress and improve postoperative outcomes. A better understanding of how the microvasculature responds to stress in elderly individuals with low fitness is thus needed. Objective: To define the relationship between cardiorespiratory fitness and microvascular resiliency to stress in elderly individuals. Hypothesis: Elderly individuals with low cardiorespiratory fitness will show acute reductions in acetylcholine (Ach)-mediated dilation of the skin microvasculature following the physiological stressful stimulus of high intensity interval exercise (HIIE). Methods: This was a prospective, observational study that enrolled elderly individuals aged 65-85 years from the community. Each participant was asked to complete two study visits. During visit 1, participants completed the Frailty Index and performed a graded cardiopulmonary exercise test (CPET) on a cycle ergometer with a metabolic cart to measure peak total body oxygen consumption (VO2 Peak). During visit 2, laser Doppler flowmetry with dermal microdialysis was performed on the ventral forearm to measure peak cutaneous microvascular vasodilation to Ach (10 mM). After baseline assessment, the participants performed a HIIE protocol where they repetitively switched between exercising at 70% of the peak workload achieved during the CPET for 60 seconds, followed by a 60 second active recovery at 10 watts. These intervals were repeated 12 times, for a total exercise duration of 24 min. Thirty minutes following exercise, Ach-mediated dilation of the cutaneous microvasculature was reassessed. Maximum dilator capacity of each site was assessed by infusing sodium nitroprusside (28 mM) and heating the skin to 43 °C. Results: Six individuals (1 male, 5 females; mean age 68 ±4 years) completed all study procedures. Based on age- and sex-predicted normative values for VO2 Max, three of the individuals had high physical fitness while three had low fitness (mean VO2 Peak = 27.5±1.1 vs. 13.6±3.4 ml/kg/min, respectively). Prior to HIIE there was no difference in peak dilation to Ach between the individuals with high vs. low fitness (% max dilation = 72±13 vs. 83±13, respectively). During HIIE, the individuals reached a Borg rating of perceived exertion of 15±4 (out of 20) and their peak heart rate was 74±15% of their age-predicted maximum. Ach-mediated dilation of the dermal microvasculature was reduced following HIIE in elderly individuals with low cardiorespiratory fitness (pre vs. post % maximum dilation = 82±13 vs. 49±27, respectively; mean change = -34±40 %) but unchanged in those with high fitness (pre vs. post % maximum dilation = 72±13 vs. 78±10, respectively; mean change = 5±3 %). Using Pearson correlation tests there was a strong correlation between the change in peak Ach-mediated dilation pre vs. post HIIE and both VO2 Peak (r=0.82, p=0.04) and Frailty Index score (r=-0.98, p<0.001). Conclusion: Microvascular resilience to acute stress is decreased in elderly individuals with low cardiorespiratory fitness compared to those with high fitness. None. 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.

Nocturnal Heart Rate Response to Spontaneous Arousals Following Sleep Restriction

Short sleep duration is associated with future cardiovascular disease including hypertension, especially in females, but mechanistic evidence is largely lacking. Experimental sleep restriction has been shown to cause short sleep-mediated tachycardia and reduced heart rate variability, indicative of autonomic cardiac instability, in some but not all studies. Heart rate (HR) response to spontaneous cortical arousals can be regarded as an index of autonomic cardiac control given its characteristic temporal pattern. Whether the HR response to cortical arousals is altered during experimental sleep restriction remains unknown. We hypothesized that sleep restriction would result in augmented HR reactivity to spontaneous arousals, and that this response would be more marked in females. We studied 19 young, healthy subjects (eight females, age: 23.5 ± 5 years, body mass index [BMI]: 24.5 ± 3.6 kg/m2). In a randomized, crossover design, participants were tested during a normal sleep (NS, 9 hr sleep opportunity) or sleep restriction (SR, 4 hr sleep opportunity) study arm. Each 16-day study visit consisted of a 4-day study acclimation phase, 9-day experimental sleep perturbation segment, followed by a 3-day recovery period. An overnight polysomnography (PSG) study was conducted on study days 2, 5 and 11 (at baseline and after 1 and 7 days of restricted versus control sleep). A registered PSG technician provided sleep staging and spontaneous arousal scoring, which was confirmed by an investigator with sleep expertise (IMG). For each identified spontaneous arousal, the HR change was quantified for 30 cardiac cycles post-arousal onset and compared to a pre-arousal baseline (average HR 5 – 10 cardiac cycles prior to arousal). An arousal was considered valid for analysis if at least one minute of stage N2 or rapid eye movement (REM) sleep occurred following sleep stage transition and was at least 30 seconds apart from other sleep disturbance-related events (e.g., limb movement, apneic event, etc.). Given low prevalence of slow wave sleep (SWS) arousals, arousals occurring in that sleep stage were excluded from present analysis. Statistical analysis, including repeated measures ANOVA (RMANOVA, p < 0.05) with condition and time (cardiac cycles) as within-subjects factors and sex as the between-subjects factor, was conducted to compare the beat-to-beat HR response to arousal between study conditions. Additionally, average and peak HR responses to spontaneous arousals were compared via RMANOVA with condition and time (study days) as within-subjects and sex as between-subjects factors. HR response to spontaneous arousal in stage two and REM sleep was similar between NS and SR on study day 5 or day 11 (condition × time: p = 0.943, 0.865). Secondary analysis of average and peak HR responsiveness to spontaneous arousals in stage two and REM sleep between conditions and study days was also not statistically different (condition × time: p = 0.193, 0.185). Last, no significant sex differences were detected across comparisons (condition × time × sex: p > 0.05 for all). These findings suggest that a 9-day sleep restriction paradigm may not alter cardiac autonomic function in otherwise healthy adults. Future work is warranted to determine whether these results extend to individuals with established cardiovascular risk factors or cardiovascular disease. Support: NIH T32-DK007013, R01-114676, and CTSA grant UL1-TR002377. 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.

Abstract 2123: Evaluation Of Autonomic Neuropathy In Patients With T2DM By Measuring R-R Interval During Rest, Standing And Deep Breathing

Objective: In patients of diabetes mellitus (DM), heart rate variability (HRV), an index of autonomic nervous system activity, tends to be lower than in healthy individuals. This reduction in HRV is associated with an increased risk of cardiovascular diseases. We aimed to evaluate HRV under varying conditions with novel indicators in patients with DM. Methods: The patients were recruited from patients with type 2 DM (T2DM) aged 20 to 79 years old from two facilities from January 2020 to December 2023. The control comprised patients without DM. Patients taking oral corticosteroids, adrenergic agonists and antagonists, and those with malignant tumors were excluded. Heart rate (HR) was measured under varying conditions of rest, standing and deep breathing (inhalation and exhalation alternating every 5 seconds). The R-R interval variation was continuously recorded in each segment of 33 beats. Subsequently, the peak HRs for each load were obtained: minimum HR during rest (mHr), maximum HR during standing (MHs), and minimum HR during deep breathing (mHb). Additionally, the SD-RR for each load was calculated. Results: We analyzed a total of 117 subjects, including 75 with T2DM and 42 without DM. The participant demographics were as follows: mean age of 55.4±13.9 years, BMI of 25.9±5.6, eGFR of 71.5±26.1 mL/min/1.73m 2 , HbA1c of 7.31±2.26 %, with 46 % of male, and duration of T2DM in patient group at 8.2±8.3 years. The subjects were categorized into three groups: G1 - non DM with CV-RR≧2, G2 - T2DM with CV-RR≧2, and G3 - T2DM with CV-RR<2.mHr was G1: 64.5±7.4, G2: 69.4±7.7, G3: 75.2±13.1 (beats/minute, p<0.001). G3 is markedly higher than G1 and G2. Furthermore, the HR change ratio from mHr to MHs was: G1: 1.36±0.12, G2: 1.31±0.11, G3: 1.22±0.10 (p<0.001). G3 is markedly lower than G1 and G2. The HR change ratio from mHr to mHb was: G1: 0.99±0.04, G2: 0.96±0.05, G3: 0.96±0.05 (p=0.043), with G3 being markedly lower than G1. The SD-RR during rest was: G1: 26.4±18.6, G2: 28.0±12.5, G3: 10.1±4.4 (p<0.001), with G3 being markedly lower than G1 and G2. Conclusion: Assessing R-R intervals under varying conditions of rest, standing, and deep breathing can indicate autonomic nervous system dysfunction among patients with T2DM.

Efficacy of pulmonary telerehabilitation on exercise tolerance, fatigue, perceived exertion, depression, and quality of life in COVID-19 survivors

INTRODUCTION: Telerehabilitation advanced significantly with the emergence of COVID-19 and the recommendation of limiting physiotherapist-patient contact time whenever practicable. The effectiveness of telerehabilitation on those who had a longer stay in hospital and on oxygen support following discharge is still under question. OBJECTIVES: To evaluate the effects after six weeks of pulmonary telerehabilitation on exercise tolerance, fatigue level, perceived exertion, symptoms of depression and quality of life in patients surviving COVID-19. MATERIALS AND METHODS: A quasi-experimental study was conducted on 25 post-COVID-19 patients following discharge in a home environment setting. The participants were advised to prepare equipment such as oxygen concentrator, B-type oxygen cylinder (backup), lengthy oxygen tubes, finger pulse oximeter, mini static pedal exerciser, incentive spirometry, weight cuffs or water bottles and sandbags. After six weeks of telerehabilitation, the patients underwent assessments including initial oxygen saturation (SPO2), heart rate, peak oxygen demand during exercise to maintain baseline SPO2, peak heart rate, maximum drop in SPO2, recovery time to baseline SPO2 measured with a pulse oximeter and stopwatch, peak perceived exertion using the Borg Dyspnea Scale, peak fatigue score using the visual analog scale (VASF), quality of life assessed with the SF-36 questionnaire, and mental health status evaluated with the Hamilton Depression Scale (HAMD). One-way repeated measure ANOVA and paired t-test were used. RESULTS: Significant improvements following the intervention on the initial SPO2 (F (2.12, 23.13) = 21.0, p<0.05) and heart rate (F (1.839, 20.23) = 43.73, p<0.05), peak maximum oxygen demand during exercise to maintain baseline SPO2 (F (1.487, 16.36) = 8.96, p<0.05), peak maximum perceived exertion (F (5, 55) = 112.51, p<0.05), peak maximum fatigue score (F (1.755, 19.30) = 67.44, p<0.05), peak heart rate (F (1.798, 19.78) = 50.99, p<0.05), peak drop in SPO2 (F (2.467, 27.14) = 41.46, p<0.05) and peak recovery time to achieve baseline SPO2 (F (5, 55) = 78.89, p<0.05). Six-week post-analysis on the depressive symptoms (mean difference =11.25, p< 0.05) and quality of life also showed significant improvement (mean difference =29.92, p< 0.05). CONCLUSION: Six weeks of comprehensive pulmonary telerehabilitation with simple equipment improved tolerance to exercise, fatigue, perceived exertion, symptoms of depression and quality of life for post-COVID-19 patients.

Feasibility of Continuous Bronchoscopy During Exercise in the assessment of large airway movement in healthy subjects.

Excessive dynamic airway collapse (EDAC) is a recognized cause of exertional dyspnea arising due to invagination of the trachea and/ or main bronchi. EDAC is typically assessed by evaluating large airway movement with forced expiratory maneuvers. This differs from the respiratory response to exercise hyperpnea. We aimed to evaluate large airway movement during physical activity, with continuous bronchoscopy during exercise (CBE), in healthy subjects and compare findings with resting bronchoscopic maneuvers and imaging techniques. Twenty-eight individuals were recruited to complete two visits including treadmill-based CBE, to voluntary exhaustion and cine magnetic resonance imaging (MRI) with forced expiratory maneuvers at rest. 25 subjects (aged 29 (26 - 33) years, 52% female) completed the study (n=2 withdrew before bronchoscopy, and one was unable to tolerate insertion of bronchoscope). The majority (76%) achieved a peak heart rate of >90% predicted during CBE. The procedure was prematurely terminated in five subjects (n=3; elevated blood pressure and n=2; minor oxygen desaturation). The CBE assessment enabled adequate tracheal visualization in all cases. Excessive dynamic airway collapse (tracheal collapse ≥50%) was identified in 16 subjects (64%) on MRI, and in 6 (24%) individuals during resting bronchoscopy, but in no cases with CBE. No serious adverse events were reported, but minor adverse events were evident. The CBE procedure permits visualization of large airway movement during physical activity. In healthy subjects, there was no evidence of EDAC during strenuous exercise, despite evidence during forced maneuvers on imaging, thus challenging conventional approaches to diagnosis.

Accurate Prediction Equations for Ventilatory Thresholds in Cardiometabolic Disease When Gas Exchange Analysis is Unavailable: Development and Validation.

To develop and validate equations predicting heart rate (HR) at the first and second ventilatory thresholds (VTs) and an optimized range-adjusted prescription for patients with cardiometabolic disease (CMD). To compare their performance against guideline-based exercise intensity domains. Cross-sectional study involving 2,868 CMD patients from nine countries. HR predictive equations for first and second VTs (VT1, VT2) were developed using multivariate linear regression with 975 cycle-ergometer cardiopulmonary exercise tests (CPET). 'Adjusted' percentages of peak HR (%HRpeak) and HR reserve (%HRR) were derived from this group. External validation with 1,893 CPET (cycle-ergometer or treadmill) assessed accuracy, agreement, and reliability against guideline-based %HRpeak and %HRR prescriptions using mean absolute percentage error (MAPE), Bland-Altman analyses, intraclass correlation coefficients (ICC). HR predictive equations (R²: 0.77 VT1, 0.88 VT2) and adjusted %HRR (VT1: 42%, VT2: 77%) were developed. External validation demonstrated superiority over widely used guideline-directed intensity domains for %HRpeak and %HRR. The new methods showed consistent performance across both VTs with lower MAPE (VT1: 7.1%, VT2: 5.0%), 'good' ICC for VT1 (0.81, 0.82) and 'excellent' for VT2 (0.93). Guideline-based exercise intensity domains had higher MAPE (VT1: 6.8%-21.3%, VT2: 5.1%-16.7%), 'poor' to 'good' ICC for VT1, and 'poor' to 'excellent' for VT2, indicating inconsistencies related to specific VTs across guidelines. Developed and validated HR predictive equations and the optimized %HRR for CMD patients for determining VT1 and VT2 outperformed the guideline-based exercise intensity domains and showed ergometer interchangeability. They offer a superior alternative for prescribing moderate intensity exercise when CPET is unavailable.

Short-duration aerobic high-intensity intervals versus moderate exercise training intensity in patients with peripheral artery disease: study protocol for a randomised controlled trial (the Angiof-HIIT Study)

IntroductionSupervised exercise training is among the first-line therapies for patients with peripheral artery disease (PAD). Current recommendations for exercise include guidance focusing on claudication pain, programme and session duration, and...

Effect of Piracetam and Iron Treatment on Heart Rate Variability in Patients With Breath-Holding Spell

BackgroundBreath-holding spells are a benign condition primarily seen in 3% to 5% of healthy children aged between six months and five years. Although no specific treatment is recommended due to its benign nature, iron and piracetam are used in severe or recurrent cases. We planned to compare the heart rate variability (HRV) before and after treatment with 24-hour Holter monitoring in patients receiving iron and piracetam treatment and investigate the treatment's effectiveness. MethodsTwenty-five patients who applied to the outpatient clinic between 2013 and 2015 due to breath-holding spells were included in the study. The patients who received piracetam and iron therapy and underwent 24-hour rhythm Holter monitoring were evaluated retrospectively. ResultsFourteen (56%) of these patients were evaluated as having cyanotic-type and 11 (44%) patients were assessed as having pale-type breath-holding spells. A significant difference was found only between hourly peak heart rate and total power in the group receiving iron treatment. Significant differences were also found among the minimum heart rate, mean heart rate, the standard deviation of RR intervals, the mean square root of the sum of the squares of their difference between adjacent RR intervals, spectpow, and low frequency before and after the treatment in the patients who started piracetam treatment (P < 0.05). ConclusionsOur study is critical as it is the first to investigate the effects of treatment options on various HRV in patients with breath-holding spells. There were statistically significant changes in HRV parameters in patients receiving piracetam, and the number of attacks decreased significantly. Piracetam treatment contributes positively to the breath-holding spell with regard to efficacy and HRV, therefore it can be used to treat breath-holding spells.

Cardiopulmonary Exercise Testing in a Prospective Multicenter Cohort of Older Adults.

Cardiorespiratory fitness (CRF) measured by peak oxygen consumption (V̇O 2peak ) declines with aging and correlates with mortality and morbidity. Cardiopulmonary exercise testing (CPET) is the criterion method to assess CRF, but its feasibility, validity, and reliability in older adults are unclear. Our objective was to design and implement a dependable, safe, and reliable CPET protocol in older adults. V̇O 2peak was measured by CPET, performed using treadmill exercise in 875 adults ≥70 yr in the Study of Muscle, Mobility and Aging (SOMMA). The protocol included a symptom-limited peak (maximal) exercise and two submaximal walking speeds. An adjudication process was in place to review tests for validity if they met any prespecified criteria (V̇O 2peak <12.0 mL·kg -1 ·min -1 ; maximum heart rate <100 bpm; respiratory exchange ratio <1.05 and a rating of perceived exertion <15). A subset ( N = 30) performed a repeat test to assess reproducibility. CPET was safe and well tolerated, with 95.8% of participants able to complete the V̇O 2peak phase of the protocol. Only 56 (6.4%) participants had a risk alert and only two adverse events occurred: a fall and atrial fibrillation. Mean ± SD V̇O 2peak was 20.2 ± 4.8 mL·kg -1 ·min -1 , peak heart rate 142 ± 18 bpm, and peak respiratory exchange ratio 1.14 ± 0.09. Adjudication was indicated in 47 tests; 20 were evaluated as valid and 27 as invalid (18 data collection errors, 9 did not reach V̇O 2peak ). Reproducibility of V̇O 2peak was high (intraclass correlation coefficient = 0.97). CPET was feasible, effective, and safe for older adults, including many with multimorbidity or frailty. These data support a broader implementation of CPET to provide insight into the role of CRF and its underlying determinants of aging and age-related conditions.

Effects of Exercise Interventions on Estimated Pulse Wave Velocity and Mean Arterial Pressure in Overweight Adults: The Role of Modality.

Estimated pulse wave velocity (ePWV) is mathematically calculated from age and mean arterial pressure (MAP). We examined the effects of high-intensity interval training (HIIT) vs. moderate-intensity continuous training (MICT) on ePWV and MAP in insufficiently active overweight adults. Using the randomized controlled trial design, thirteen males (27.46 3.80 years old; body mass index (BMI) = 29.61 5.52) randomly completed either two-week HIIT (n = 7) or MICT (n = 6). HIIT consisted of 8 sessions of cycling, 20 min/session with an exercise-to-rest ratio of 10/50 s at 90% peak heart rate ( ). MICT consisted of 8 cycling sessions, 40 min/session at 60-75% . Oscillometric brachial MAP was measured pre- and post-intervention, and ePWV was calculated. Two-way repeated measure analysis of variance examined the effects of time, intervention, and their interactions on ePWV and MAP. Significant time effects were observed for ePWV and MAP, where both measures comparably decreased over time in HIIT and MICT groups (p 0.05 for all). However, no significant intervention or interaction effects were detected, indicating no superiority of either exercise modality for ePWV or MAP improvements. This study uniquely revealed that two weeks of HIIT or MICT resulted in significant, comparable, and clinically meaningful decreases in ePWV and MAP among insufficiently active overweight adults. As such, overweight adults who have time as a constraint to engage in traditional exercise (i.e., MICT) can accomplish comparable vascular benefits by performing HIIT.

Hemodynamic and Metabolic Responses to Moderate and Vigorous Cycle Ergometry in Men Who Have Had Transtibial Amputation.

Adults who have had an amputation face barriers to having an active lifestyle which attenuates cardiorespiratory fitness. Prior studies in amputees typically involve treadmill walking or arm ergometry, yet physiological responses to bilateral leg cycling are less understood. This study assessed the hemodynamic and metabolic responses to moderate and vigorous cycle ergometry in men who have had a transtibial amputation (TTA). Five men who had had a unilateral TTA (age = 39 ± 15 yr) and six controls (CONs) without an amputation (age = 31 ± 11 yr) performed two 20 min bouts of cycling differing in intensity. Cardiac output (CO), stroke volume (SV), and oxygen consumption (VO2) were measured during moderate intensity continuous exercise (MICE) and high intensity interval exercise (HIIE) using thoracic impedance and indirect calorimetry. In response to MICE and HIIE, the HR and VO2 levels were similar (p > 0.05) between groups. Stroke volume and CO were higher (p < 0.05) in the CONs, which was attributed to their higher body mass. In men with TTAs, HIIE elicited a peak HR = 88%HRmax and substantial blood lactate accumulation, representing vigorous exercise intensity. No adverse events were exhibited in the men with TTAs. The men with TTAs show similar responses to MICE and HIIE versus the CONs.

The variability of physical enjoyment, physiological responses, and technical-tactical performance according to the bout duration of small-sided games: a comparative study between female and male soccer players

BackgroundThis study aimed to compare various factors, namely perceived enjoyment (PE), percentage of peak heart rate (%HRpeak), blood lactate (La), rating of perceived exertion (RPE), and technical-tactical performance among soccer players across different bout durations (CB: continuous bout, MIB: medium intermittent bouts, and SIB: short intermittent bouts) and between male and female players during four-a-side (4vs4) small-sided games (SSGs) including goalkeepers.Methodssixteen female soccer players (age: 20.1 ± 0.5 years old) and sixteen professional male adults (age: 20.7 ± 0.7 years old) participated in the study. SSGs (4vs4) were performed in a CB: (1 × 12 min), and in an interval format: MIB: (2 × 6 min), and SIB: (3 × 4 min) with 2 min of passive recovery. PE was collected after each SSGs. The players’ heart rate (HR) was continuously measured, whereas ratings of perceived exertion (RPE) and, blood lactate concentration ([La]) were determined at the end of each SSGs. Technical-tactical performance were analyzed during each session of SSGs. Pitch dimensions were (length x width) (25 × 32 m), and relative space per players was 100 m2.ResultsFor female soccer players, medium intermittent bouts (MIB) elicited significantly higher perceived enjoyment (PE) compared to continuous bouts (CB) (p < 0.001) and short intermittent bouts (SIB) (p < 0.01). Conversely, for male soccer players, CB resulted in higher PE compared to MIB (p < 0.001) and SIB (p < 0.001). During CB and MIB, peak heart rate (PeakHR) and percentage of peak heart rate (%HRpeak) were significantly higher in female players compared to SIB (PeakHR: CB: p < 0.001; PeakHR: MIB: p < 0.01; %HRpeak: CB: p < 0.001; %HRpeak: MIB: p < 0.01). Blood lactate (La) and rating of perceived exertion (RPE) were significantly greater in CB compared to MIB (La: p < 0.001; RPE: p < 0.01) and SIB (La: p < 0.001; RPE: p < 0.001) for female players only. For male players, CB resulted in significantly higher PeakHR, %HRpeak, La, and RPE compared to MIB (peak HR: p < 0.01, dunb = 1.35; %HR: p < 0.01; La: p < 0.01; RPE: p < 0.01) and SIB (peak HR: p < 0,01; %HR: p < 0.01; RPE: md = 0.87, p < 0.05). Regarding technical-tactical performance, in female players, the % of successful passes, successful tackles, and successful duels were higher during SIB compared to CB (p < 0.01; p < 0.001; p < 0.001) and MIB compared to CB (p < 0.01; p < 0.001; p < 0.001), while ball loss was lower during SIB compared to CB (p < 0.001) and MIB compared to CB (p < 0.001). In male players, % of successful passes and tackles were higher during CB compared to MIB (p < 0.001 and p < 0.05) and SIB (p < 0.001 and p < 0.05), while CB had a lower % of ball loss compared to MIB (p < 0.01) and SIB (p < 0.001). There was no significant difference in the % of successful duels between the bouts for either gender.ConclusionThis study showed a difference in physical enjoyment between male and female soccer players depending on the bout duration of SSGs. For that, trainers should consider intermittent bouts for female soccer players and continuous bouts for male soccer players when designing SSGs-based training in order to significantly improve PE, training load, and technical-tactical performance.

Cardiac hemodynamics phenotypes and individual responses to training in coronary heart disease patients.

In patients with coronary heart disease (CHD), individualized exercise training (ET) programs are strongly recommended to optimize peak oxygen uptake ( O2peak) improvement and prognosis. However, the cardiac hemodynamic factors responsible for a positive response to training remain unclear. The aim of this study was to compare cardiac hemodynamic changes after an ET program in responder (R) versus non-responder (NR) CHD patients. A total of 72 CHD patients completed a 3-month ET program and were assessed by cycle ergometer cardiopulmonary exercise test (CPET: O2peak assessment) with impedance cardiography (ICG) for hemodynamic measurements before and after training. Cardiac hemodynamics (e.g., CO, CI, SV, ESV, EDV, and SVR) were measured by ICG during CPET. The R and NR groups were classified using the median change in O2peak (>the median for R and ≤the median for NR). In the R group, O2peak (+17%, p < 0.001), CO, CI, SV, and HR increased by 17%, 17%, 13%, and 5%, respectively (p < 0.05) after the training program. In the NR group, O2peak, CO, CI, and SV increased by 0.5%, 5%, 8%, and 6%, respectively (p < 0.01). The SVR decreased in both groups (-19% in R and -11% in NR, p < 0.001). Among CHD patients, the R group showed a better improvement in peak cardiac output via an increase in peak stroke volume and heart rate and a reduced systemic vascular resistance than the NR group. Different cardiac phenotype adaptations and clinical individual responses were identified in CHD patients according to the aerobic fitness responder's status.

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.