Heart Rate Recovery Research Articles

Association between T2DM with high resting heart rate and abnormal heart rate recovery within one minute after treadmill exercise test in CHD patients

Background: Diabetes mellitus and coronary heart disease are chronic diseases that are very closely related. It has long been known that diabetes mellitus is a significant risk factor for coronary heart disease. The incidence of diabetes mellitus is increasing, according to data taken from the PERKENI consensus, WHO predicts an increase in the number of people with DM in Indonesia from 8.4 million in 2000 to around 21.3 million in 2030. The purpose of this study was to determine whether diabetes mellitus is related to cardiovascular autonomic neuropathy. Methods: This research method is helpful to know that diabetes mellitus is directly related to cardiovascular autonomic neuropathy so that it will affect a person's hemodynamic quality functionally. In addition, to functionally affecting a person's hemodynamic capacity, determining that a patient with cardiovascular autonomic neuropathy is determined from the high resting heart rate and abnormal recovery heart rate variables after the treadmill exercise test, we can provide information and education to patients regarding the importance of a cardiac rehabilitation program in patients with coronary heart disease. Results: A total of 45 people according to the calculation of the number of samples by type, male sex numbered 30 and female numbered 15 people. The number of patients who experienced impaired recovery of the 1-minute heart rate in this study was 25 people (55.5%) with the majority being male. And the number of sufferers who experience high heart rates at rest is 22 people (48.9%). In a bivariate analysis, patients with type 2 diabetes mellitus and without type 2 diabetes mellitus significantly worsened recovery heart rate (P value <0.05). Conclusion: There is a significant relationship between diabetes mellitus on high resting heart rate and diabetes mellitus on poor heart rate recovery in 1 minute in patients with coronary heart disease.

Correlation between Heart Rate Recovery & Global Longitudinal Strain in Heart Failure Patients Subjected to Cardiac Rehabilitation

Abstract Background Cardiac rehabilitation is a medically supervised program designed to improve cardiovascular outcomes after MI, heart failure, angioplasty, or heart surgery. It is a complex intervention that involves a variety of therapies, including supervised exercise training, health education and risk factor modification, behavior change, social and psychological support. Objective To study the correlation between heart rate recovery & global longitudinal strain in heart failure patients subjected to cardiac rehabilitation. Patients and Methods This study was conducted in the cardiac rehabilitation (CR) unit in the cardiology department of Ain Shams University hospital between December 2019 and December 2020 to investigate the correlation between heart rate recovery & global longitudinal strain in heart failure patients subjected to cardiac rehabilitation. Results Our study is the first study that investigated the correlation between HRR and GLS in ischemic heart failure patients subjected to cardiac rehabilitation. Conclusion Exercise-based cardiac rehabilitation leads to improvement in the functional capacity of ischemic heart failure patients as reflected by the improvement in HRR and also leads to IMPROVEMENT in LV functions as reflected by the improvement in GLS. Moreover, METs and HR reserve was improved significantly with CR.

Effect of Cardiac Rehabilitation on Post Exercise Systolic Blood Pressure Recovery in Patients with Impaired Left Ventricular Ejection Fraction after Recent Myocardial Infarction

Abstract Background Ischemic Heart diseases (IHD) are significant causes of morbidity and mortality worldwide with an estimated 9 million deaths each year. Exercise-based Cardiac Rehabilitation (CR) is one of the most important and cost-effective aspects of secondary prevention in patients with IHD. Post-exercise Systolic Blood Pressure Recovery (SBPR) represents an important hemodynamic parameter that is associated with the risk and severity of ischemic artery disease and future cardiovascular events. Aim of the Work The aim of this study is to assess the effect of CR on post-exercise SBPR in patients with Left Ventricular Ejection fraction less than 45% following a recent Myocardial Infarction. Patients and Methods this study included patients with Left Ventricular Ejection fraction less than 45% following a recent Myocardial Infarction, presenting to Cardiac Rehabilitation Units. the study included two groups of patients. Study group included Patients on optimal medical treatment who are attending CR sessions, and control group included patients on optimal medical treatment who refused or failed to attend more than 50% of cardiac rehabilitation sessions. SBPR was assessed in each patient before and after the CR program. Results When compared to baseline findings, both groups had statistically significant improvement in LVEF, resting SBP, recovery SBP value and HRR. However, CR group had better improvement in LVEF, lower Resting SBP, lower Peak SBP, Better SBP recovery ratio and better HRR outcomes when compared to the changes in the control group. Conclusions Cardiac Rehabilitation after recent Ischemic coronary artery event can provide significant improvement in Systolic blood pressure recovery and heart rate recovery which are important haemodynamic parameters that are associated with the significance and severity of future cardiovascular events. Abbreviations IHD: Ischemic Heart Disease; CR: Cardiac Rehabilitation; LVEF: Left Ventricular Ejection fraction; SBP: Systolic Blood Pressure

Adding objectivity to submaximal exercise testing by assessment of heart rate recovery at home—a healthy volunteer study iv (search-iv)

Adding objectivity to submaximal exercise testing by assessment of heart rate recovery at home—a healthy volunteer study iv (search-iv)

N terminal prohormone of brain natriuretic peptide is associated with improved heart rate recovery after treadmill exercise test

BackgroundHeart rate recovery (HRR) and N terminal-pro B type natriuretic peptide (NT-proBNP) are markers for survival and cardiac function; however, Little is known about their association. MethodWe examined 2540 healthy subjects aged 12–49 years with data from National Health and Nutrition Examination Survey(NHANES) 1999–2002. HRR parameters 1–3 min after exercise were calculated from exercise test results. Baseline characteristics, anthropometric and NT-proBNP, and other risk covariates were obtained. ResultThe results showed that NT-proBNP was positively correlated with HRR2(correlation coefficient (cc) = 0.042 [0.029–0.054], P < 0.001) and HRR3(cc = 0.046 [0.029–0.064], P = 0.001); with further adjustment, the associations remained significant between NT-proBNP and HRR2(cc = 0.030 [0.010–0.049], P = 0.004)/HRR3(cc = 0.029[0.004–0.054], P = 0.025). Our study also found significant correlations between NT-pro BNP and SBP(cc = −0.026 [-0.046∼-0.005], P = 0.017), DBP(cc = −0.037 [-0.062∼-0.012], P = 0.005), and total cholesterol(cc = −0.065 [-0.12∼-0.018], P = 0.009). ConclusionsOur results suggest that BNP might reduce heart rate after exercise by inhibiting the sympathetic nervous system (SNS), reducing HRR2 and HRR3, as these phases involve the reduction of heart rate through cardiac sympathetic withdrawal. Moreover, the interaction of BNP on the SNS might be related to the effect of BNP on cardiovascular risks.

Abstract P2079: Heart Rate Variability And Chronotropic Incompetence As Prognostic Markers In A Preclinical Model Of HFpEF

The prevalence of heart failure with preserved ejection fraction (HFpEF) in developed countries is increasing alarmingly. This is in part due to an increase in comorbid diseases (obesity, diabetes, hypertension), and risk factors (age, stress, and low physical activity). HFpEF patients often present with chronotropic incompetence (CI) and impaired heart rate variability (HRV), and both CI and decreased HRV are used as prognostic markers of heart disease and sudden cardiac death in clinical studies. In preclinical HFpEF models, however, CI and HRV are not commonly evaluated, and the efficacy of novel compounds is determined primarily through echocardiography results. Thus, there is a need to align efficacy readouts to enhance the translatability of novel compounds from preclinical to clinical stages. Here we sought to determine the utility of CI and HRV in preclinical HFpEF studies in a novel 2-hit HFpEF model; the metabolic syndrome non-alcoholic steatohepatitis mouse with AAV overexpression of renin (MS-NASH+Renin). To collect continuous and conscious electrocardiogram and blood pressure data, C57BL/6 (n=10) and MS-NASH (formerly FATZO, n=32) male mice were implanted with radiotelemeters at 20 weeks and iv injected with either AAV-Vector or AAV-Renin. To assess disease burden, CI and HRV, we acquired and analyzed body weight, electrocardiography, peak VO2, exercise HR, and echocardiography data once a month for 5 months. We found that MS-NASH mice have increased body weight regardless of treatment, and that renin treatment increased blood pressure for both C57BL/6 and MS-NASH mice. Peak VO2, time to exhaustion, distance traveled, and maximum and recovery HR are significantly decreased in MS-NASH mice, indicating CI. HRV is also significantly decreased in MS-NASH mice when compared to C57BL/6. Interestingly, renin treatment did not further decrease treadmill performance or HRV for MS-NASH mice. However, MS-NASH+Renin mice did have decreased functional capacity with preserved ejection fraction and altered heart structure. These results suggest that MS-NASH+Renin is a model for HFpEF, and that CI and HRV are translatable markers for HFpEF. In the future, we will evaluate the use of CI and HRV in preclinical HFpEF drug development studies.

Whole-body cooling effectiveness of cold intravenous saline following exercise hyperthermia: a randomized trial

IntroductionIn some athletic, occupational, military and emergency settings, cold intravenous (IV) fluids are used to facilitate whole-body cooling in an effort to treat heat illness. This treatment has anecdotal support, but currently lacks evidence supporting it as a whole-body cooling modality. Other modalities may offer superior cooling rates, and thus, patient outcomes following treatment. We sought to evaluate cooling rates of cold-IV normal saline immediately following exercise-induced hyperthermia. MethodsEight healthy participants (3 females; 25 ± 2y; 72.9 ± 10.9 kg) completed 2 trials in random order. Prior to exercise, participants provided a small urine sample to confirm hydration status via urine specific gravity. Wet bulb globe temperature (WBGT) was assessed throughout trials. In both trials, participants exercised outdoors until rectal temperature (Tre) reached ∼38.9 °C, or volitional exhaustion, and then were cooled. In cooling, participants received either cold-IV (∼5 °C 0.9% NaCl fluids) or no treatment (sat in the shade; passive). Throughout exercise and treatment, Tre and heart rate (HR) were monitored. During exercise and every 10 min throughout cooling, participants were asked to assess thermal sensation. ResultsHydration status (P = .847) was not significantly different prior to exercise between trials. WBGT throughout was not different between trials (P = .426). Maximum Tre reached was not different between cold-IV (38.88 ± 0.30 °C) and passive cooling (38.76 ± 0.28 °C) trials (P = .184). Mean cooling rate for cold-IV (0.039 ± 0.005 °C·min−1) was significantly greater than for passive cooling (0.028 ± 0.005 °C·min−1; P = .002). Tre throughout cooling was not different between trials (P = .707), but did decrease throughout (P = .008), regardless of trial. HR was decreased over time (P < .001), but cold-IV and passive cooling were not different throughout HR recovery (P = .141). Thermal sensation decreased throughout cooling (P < .001), but was not different between trials (p = .278). ConclusionEmergency medical personnel should adopt treatment protocols that employ documented effective treatments for exertional heat stroke. In isolation, our data casts significant doubt for the use of cold-IV saline infusion for whole-body cooling of hyperthermic individuals.

Myc beyond Cancer: Regulation of Mammalian Tissue Regeneration.

Myc is one of the most well-known oncogenes driving tumorigenesis in a wide variety of tissues. From the brain to blood, its deregulation derails physiological pathways that grant the correct functioning of the cell. Its action is carried out at the gene expression level, where Myc governs basically every aspect of transcription. Indeed, in addition to its role as a canonical, chromatin-bound transcription factor, Myc rules RNA polymerase II (RNAPII) transcriptional pause-release, elongation and termination and mRNA capping. For this reason, it is evident that minimal perturbations of Myc function mirror malignant cell behavior and, consistently, a large body of literature mainly focuses on Myc malfunctioning. In healthy cells, Myc controls molecular mechanisms involved in pivotal functions, such as cell cycle (and proliferation thereof), apoptosis, metabolism and cell size, angiogenesis, differentiation and stem cell self-renewal. In this latter regard, Myc has been found to also regulate tissue regeneration, a hot topic in the research fields of aging and regenerative medicine. Indeed, Myc appears to have a role in wound healing, in peripheral nerves and in liver, pancreas and even heart recovery. Herein, we discuss the state of the art of Myc's role in tissue regeneration, giving an overview of its potent action beyond cancer.

Cardiovascular capacity in adults with obstructive sleep apnoea.

BACKGROUND: Obstructive sleep apnoea (OSA) patients have a decreased exercise capacity. Potential cardiovascular capacity in patients with OSA with different severity without known cardiovascular disease has not been described.OBJECTIVE: To evaluate impaired potential exercise cardiovascular capacity during cardiopulmonary exercise testing (CPET) in OSA patients and to compare cardiovascular performance reaction with different severity during graded exercise stages.DESIGN: All participants were accompanied without cardiovascular disease, especially hypertension and arrhythmia. Parameters of different stages were compared between subjects with and without OSA, and among OSA patients with varied severity.RESULTS: Despite having significantly higher peak exercise diastolic blood pressure (DBP) and ventilatory equivalent for CO2 (EQCO₂), patients with OSA had a lower peak oxygen uptake (VO₂), heart rate (HR), heart rate recovery (HRR) and respiratory reserve (BR) than normal subjects. Furthermore, significant correlations were found between VO₂, DBP, EQCO₂, HRR, BR and the apnoea-hypopnea index. In severe OSA, there was a greater difference in HR and HRR during the anaerobic threshold stages.CONCLUSIONS: OSA patients demonstrate reduced potential cardiovascular capacity, even without documented cardiovascular disease. Patients with severe OSA develop impaired exercise capacity at early stage during exercise. These data point to exaggerated haemodynamic response to graded exercise and delayed post-exercise cardiovascular response recovery in OSA patients. CPET can be a supplement for assessment of OSA severity.

Effect of tele-yoga on aerobic capacity, respiratory muscle strength, and cognitive performance in patients with obstructive sleep apnea syndrome

BackgroundObstructive sleep apnea syndrome (OSAS) causes a decrease in aerobic capacity, respiratory muscle strength, and cognitive function, negatively affecting health-related quality of life. ObjectivesThis study aimed to compare aerobic capacity, respiratory muscle strength, cognitive performance, functional capacity, sleep quality and daytime sleepiness in OSAS patients practicing and not practicing tele-yoga (TY). Methods44 OSAS patients (40 M, 4F) were randomized into TY and control groups. TY group underwent live synchronous group-based TY sessions, 60 min/day, three days/week, for 12 weeks. Control group performed unsupervised thoracic expansion exercises at home 4 times daily for 12 weeks. The following were evaluated at baseline and at the end of the 6th and 12th weeks: inspiratory and expiratory respiratory muscle strength (MIP, MEP), cardiopulmonary exercise test, Corsi Block Tapping Test (CBTT) and Stroop TBAG test, six-minute walk test (6MWT), Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS). ResultsTY significantly improved MIP, and exercise test parameters (VE, HRmax,%HR, heart rate recovery in the first minute and RQmax), CBTT (forward) and Stroop TBAG test scores (parts of 3,4,5) compared to the controls (p<0.05). There were no significant changes 6MWT in the TY group compared to the control group (p > 0.05). Sleep duration (min), sleep efficiency, sleep quality of PSQI and ESS score improved significantly in the TY group compared to the control group (p < 0.05). ConclusionWe suggest including TY intervention as a method of exercise in addition to CPAP treatments since it improves the health-related parameters of OSAS patients.

Effects of Cycle Ergometer Training on Heart Rate Recovery and Mind Fullness in NYHA class I, II Heart Failure Patients

Aim: To determine effect of Cycle ergometer on heart rate recovery and mindfulness in NYHA Class I and II heart failure pts. Study design: The study was a randomized controlled trial. Place and duration: Total study duration was 6 months, carried out at Rawal general and dental hospital Islamabad. Methodology: 38 patients were divided into the Control and experimental group. The control group received only conventional Therapy at home and the hospital on the third and 6th weeks for a supervised conventional therapy session. The experimental group received conventional therapy and cycle ergometer training thrice weekly for six weeks. Baseline demographic data, Vitals, HRR1, HRR2, and MAAS scores were gathered from both groups and compared after six weeks. Results: The mean age of the control group was (46.37±4.43) and of the experimental group (was 50.47±9.22). The MAAS score was significant with a p-value (&lt; 0.05). HRR1 and HRR2 were also significant, with a p-value (&lt;0.05). Conclusion: This study showed that cycle ergometer exercise training significantly improved heart rate recovery in NYHA Class I and II heart failure patients and improved mindfulness. Keywords: Heart failure, Heart Rate Recovery 1(HRR1), Heart Rate Recovery 2 (HRR2), Mindful Attention Aware Scale

An inconsistent social buffering effect from a static visual substitute in horses (Equus caballus): A pilot study

Social buffering occurs when a companion helps to reduce a subject’s stress response during a stressful event and/or to recover more quickly from a stressful event. The aim of this study was to determine if any social buffering function of a horse companion can occur in relation to a visual substitute (poster of a relaxed horse face) during two different stressful situations: a novel object test (a ball presented gradually) and an umbrella test (sudden opening of an umbrella). In order to evaluate the effect of a horse face poster on the subject’s stress responses, behavioral (reactivity score) and physiological (heart rate) measurements were taken. Each of the 28 study subjects completed four trials: two novel object tests and two umbrella tests—each with a relaxed horse face poster and a pixelated poster (control). Our results showed that the presence of a horse face poster might significantly reduce the behavioral response (reactivity) of subject horses in the novel object test but did not improve heart rate recovery (HRR) time. The horse face poster did not have a significant effect on the behavioral reaction or HRR in the umbrella test. Any effect of a horse face poster as a potential social buffer might potentially depend on the nature of the stressful event.

Donor utilization in heart transplant with donation after circulatory death in the United States

Heart transplantation using donation after circulatory death (DCD) was recently adopted in the United States. This study aimed to characterize organ yield from adult (≥18 years) DCD heart donors in the United States using the United Network for Organ Sharing registry. The registry does not identify potential donors who do not progress to circulatory death, and only those who progressed to death were included for analysis. Outcomes included organ recovery from the donor operating room and organ utilization for transplant. Multiple logistic regression was used to identify predictors of heart recovery and utilization. Among 558 DCD procurements, recovery occurred in 89.6%, and 92.5% of recovered hearts were utilized for transplant. Of 506 DCD procurements with available data, 65.0% were classified as direct procurement and perfusion and 35.0% were classified as normothermic regional perfusion (NRP). Logistic regression identified that NRP, shorter agonal time, younger donor age, and highest volume of organ procurement organizations were independently associated with increased odds for heart recovery. NRP independently predicted heart utilization after recovery. DCD heart utilization in the United States is satisfactory and consistent with international experience. NRP procurements have a higher yield for DCD heart transplantation compared with direct procurement and perfusion, which may reflect differences in donor assessment and acceptance criteria.

Effects of childhood obesity on myocardial performance, autonomic and conduction properties of the heart.

Childhood obesity tends to persist into adulthood and associated with increase in developing ischemic and non-ischemic cardiovascular diseases. We aimed to evaluate the effect of obesity on cardiac functions, atrial electromechanical coupling, and heart rate response, which are considered to be predictors of atrial fibrillation and sudden cardiac arrest. Study population included 52 obese children and 52 healthy controls. We performed 12-lead electrocardiography, echocardiographic examination, and treadmill exercise testing. Mitral, septal, and tricuspid segments were analysed by tissue Doppler imaging. Myocardial performance index (p = 0.011, p < 0.001, and p = 0.001, respectively) was higher and E'/A' ratio (p = 0.011, p < 0.001, and p < 0.001, respectively) was lower in obese group than controls. Atrial electromechanical coupling was longer in the obese group at all three segments (p < 0.001, p = 0.009, and p = 0.04, respectively). They had significantly longer interatrial (p < 0.001) and intra-atrial (p = 0.003) electromechanical conduction delay. While chronotropic index was similar between two groups, heart rate reserve was lower in obese children than controls (p = 0.043). The 1st- and 2nd-minute heart rate recovery indices of the obese group were lower compared to controls (p < 0.001 and p = 0.03, respectively). Body mass index was positively correlated with intra- and inter-atrial conduction times, whereas it was negatively correlated with heart rate recovery indices. We showed a deterioration in the diastolic function, atrial conduction, and heart rate response properties in children with obesity. Given the prognostic importance of these parameters, obese patients are might be at risk for atrial fibrillation and severe dysrhythmias from a young age.

Camera-based Cardiovascular Screening based on Heart Rate and Its Variability In Pre- and Post-Exercise Conditions.

Analysis of heart rate (HR) and heart rate variability (HRV) in pre- and post-exercise conditions can provide useful information about the health condition of cardiovascular system. Remote photoplethysmography (rPPG) that uses a contactless camera to measure vital signs from the human face might allow for ubiquitous applications in the fitness scenario. This paper benchmarks the accuracy of HR and HRV measured by ECG, PPG and rPPG, and investigates the difference of HR and HRV parameters between individuals with/without the exercise habit in pre- and post-exercise phases. We built a fitness benchmark consisting of 14 healthy subjects to perform running exercise on a treadmill, with video and reference data recorded simultaneously. The results show that rPPG has a similar performance as PPG in both the estimation of HR and HRV. The HRV parameters (Mean IBI, SDNN, LF, VLF, and SD2) of rPPG/PPG show good agreements with the ECG reference. Subjects with a regular exercise habit show lower resting HR and smaller values of HRV parameters in pre-exercise phase, fewer changes in HR and HRV at the same exercise intensity, and faster HR recovery after exercising, as compared with those without an exercise habit. The preliminary results suggest that rPPG is a promising surrogate of PPG for screening HR and HRV before and after exercise, to indicate the performance of cardiac training.

Prognostic value of the post-exercise heart rate recovery and BHDE-index in chronic obstructive pulmonary disease

BackgroundThe BODE index, consisting of body mass index (B), airflow obstruction (O), dyspnea score (D), and exercise capacity (E), can predict outcomes in COPD. However, when spirometry was restricted to prevent cross-infection such as COVID-19 pandemic, a modified index would be needed. Because cardiovascular dysfunction is associated with poor clinical outcomes in COPD, we conducted a novel BHDE-index by replacing spirometry with post-exercise heart rate recovery (HRR, H) and evaluated its predictive performance in this observational study.MethodsFrom January 2019 to December 2019, enrolled patients were analyzed as a derivation cohort for the setup of the model. This model was verified in another group of patients generated between January 2020 and December 2020, as the validation cohort. The post exercise HRR was defined as the difference of heart rate immediately after and 1 min after test cessation.ResultsA total of 447 patients with COPD were enrolled. Patients with abnormal HRR were older, with more severe airway obstruction, severe airway symptoms, faster resting heart rate, shorter 6-min walk distance and higher frequency of severe acute exacerbation in previous one year. The prediction performance of the BHDE-index for one-year severe COPD exacerbation was similar to that of the BODE-index in both the derivation and validation groups [area under the receiver operating characteristic curve (AUROC) 0.76 vs. 0.75, p = 0.369; AUROC 0.74 vs. 0.79, p = 0.05]. The prediction performance for 1 year mortality was also similar between BHDE-index and BODE-index in both cohorts [AUROC 0.80 vs. 0.77, p = 0.564; 0.76 vs. 0.70, p = 0.234]. Univariate and multivariate analyses also showed that the BHDE-index was an independent and important predictor of annual severe COPD exacerbation in the derivation and validation cohorts.ConclusionsThe BHDE-index is a good and easy-to-perform prediction model for the risk of severe acute exacerbation and 1-year mortality in COPD wherever spirometry results are unavailable.

Cardiovascular fitness is associated with child adiposity at 5 years of age: findings from the ROLO longitudinal birth cohort study

BackgroundCardiovascular fitness is strongly linked with metabolic risk; however, research is limited in preschool children. Although there is currently no simple validated measure of fitness in preschool children, heart rate recovery has been highlighted as an easily accessible and non-invasive predictor of cardiovascular risk in school-aged children and adolescents. We aimed to investigate whether heart rate recovery was associated with adiposity and blood pressure in 5-year-olds.Study designThis is a secondary analysis of 272 5-year-olds from the ROLO (Randomised cOntrol trial of LOw glycaemic index diet in pregnancy to prevent recurrence of macrosomia) Kids study. Three-minute step tests were completed by 272 participants to determine heart rate recovery duration. Body mass index (BMI), circumferences, skinfold thickness, heart rate, and blood pressure were collected. Independent t-tests, Mann-Whitney U, and Chi-square tests were used to compare participants. Linear regression models examined associations between heart rate recovery and child adiposity. Confounders included child sex, age at study visit, breastfeeding, and perceived effort in the step test.ResultsThe median (IQR) age at the study visit was 5.13 (0.16) years. 16.2% (n = 44) had overweight and 4.4% (n = 12) had obesity based on their BMI centile. Boys had a quicker mean (SD) heart rate recovery after the step test than girls (112.5 (47.7) seconds vs. 128.8 (62.5) seconds, p = 0.02). Participants with a slower recovery time (> 105 s) had higher median (IQR) sum of skinfolds (35.5 (11.8) mm vs. 34.0 (10.0) mm, p = 0.02) and median (IQR) sum of subscapular and triceps skinfold (15.6 (4.4) mm vs. 14.4 (4.0) mm, p = 0.02) compared to participants with a quicker recovery time. After adjusting for confounders (child sex, age at study visit, breastfeeding, effort in the step test), linear regression analyses revealed heart rate recovery time after stepping was positively associated with sum of skinfolds (B = 0.034, 95% CI: 0.01, 0.06, p = 0.007).ConclusionChild adiposity was positively associated with heart rate recovery time after the step test. A simple stepping test could be used as a non-invasive and inexpensive fitness tool in 5-year-olds. Additional research is needed to validate the ROLO Kids step test in preschool children.

Social security: can rattlesnakes reduce acute stress through social buffering?

Social buffering comprises the reduction of stress an organism experiences when in the presence of a companion and has been well documented in highly social animals, such as birds and mammals. To date, it has not been reported in reptiles. Rattlesnakes are cryptically social, exhibiting kin recognition and forming subtle social networks in certain contexts. We tested for the presence of social buffering against an acute stressor in 25 wild-caught adult southern Pacific rattlesnakes (Crotalus helleri) by measuring heart rate increase during a standardized disturbance when alone, in the presence of a rope (inanimate object control), and in the presence of a same-sex companion. We further tested for a greater proclivity of social buffering in montane snakes, which overwinter communally, than in lowland snakes, which mostly overwinter alone; and for a greater proclivity in females, which often aggregate during gestation and maternally attend their offspring. Results indicated that the presence of a companion significantly reduced emotional tachycardia (change in heart rate) after disturbance compared to the other treatments. We detected no difference in social buffering proclivity between montane and lowland populations, but lowland snakes exhibited a subdued acute stress response across treatments and had a longer heart rate recovery time. No difference in emotional tachycardia existed between the sexes. This novel study can benefit our understanding of social buffering, including its expression, adaptive roles, and practical applications for captive animals.

Pilot Study on Exercise Performance Level and Physiological Response According to Rest Intervals between Sets during 65% 1RM Bench Press Exercise

The purpose of this study was a pilot study to determine the performance level and physiologic responses (heart rate and heart rate recovery (%)) of six different rest interval conditions during the performance of seven sets of a 65% 1RM bench press exercise. Eight healthy male university students who were 20 years of age and enrolled at University C were tested. The subjects’ bench press 1RM was measured before the experiment, and they performed bench press exercises with six different rest intervals (30 s, 1 min, 2 min, 3 min, 4 min, and 5 min), which were randomized and crossed over. The experimental measurements were performed once a week and repeated six times per rest interval condition (six intervals) to minimize the learning effect for the subjects. A two-way repeated measures ANOVA was used to verify the data, post-comparison (contrast: repeat) was used to establish statistical significance, and the following results were obtained. First, the level of exercise performance (reps) between sets across the six rest interval conditions showed significant differences (p &lt; 0.000) and high effect sizes (ES ≥ 0.70) across the rest interval conditions. In addition, more reps (in terms of volume) were performed in the relatively longer rest interval conditions. The number of reps over the progression of the sets also showed a significant difference (p &lt; 0.000) for the shorter rest interval condition, with a high effect size (ES ≥ 0.64). There was also an interaction effect (p &lt; 0.000) between the rest interval condition and the set, with the number of repetitions at the beginning of the set decreasing significantly as the set progressed for the relatively short rest interval condition, with a high effect size (ES ≥ 0.60). Second, there was no statistically significant difference in after-exercise heart rate among the rest interval conditions between sets, but the longer rest interval conditions of 4 and 5 min showed a significant difference (p &lt; 0.005) as the set progressed, with a high effect size (ES ≥ 0.41). In each of the six rest interval conditions, heart rate levels were similar in sets 1 and 2 but increased from set 3 to set 7. Immediately after each bout of exercise, the resting heart rate according to rest interval condition was statistically highest in the shorter rest intervals (30 s, 1 min), with a high effect size (p &lt; 0.020) and a high ES ≥ 0.39. Heart rate was also higher in the 2, 3, 4, and 5-min rest intervals, and increased significantly (p &lt; 0.000) as the sets progressed, with a high effect size. Third, heart rate recovery (%) according to the rest interval condition between sets was significantly higher in the longer rest interval conditions (1, 2, 3, 4, and 5 min) than in the 30 s rest interval condition (p &lt; 0.039), with a high effect size (ES ≥ 0.37). In addition, heart rate recovery in all rest interval conditions significantly decreased as the sets progressed (p &lt; 0.05), with a high effect size (ES ≥ 0.37). Taken together, there were significant differences in performance levels (reps), physiological responses, and recovery between rest interval conditions during the equal-intensity resistance exercises in this study. Furthermore, the performance levels between rest interval conditions during the 65% 1RM bench press exercise in this study suggest that rest intervals of 2–3 min may be effective for improving muscular endurance, while rest intervals of 4–5 min may be effective for improving muscle hypertrophy. This suggests that manipulating the rest intervals between sets during resistance training at the same intensity may lead to better training outcomes.

Evaluation of a new treadmill exercise protocol to unmask type 1 Brugada electrocardiographic pattern: can we improve diagnostic yield?

High precordial leads (HPL) on the resting electrocardiogram (ECG) are widely used to improve diagnostic detection of type 1 Brugada ECG pattern (Br1ECGp). A parasympathetic activation marks the initial recovery phase of treadmill stress testing (TET), and this can be useful for detecting the typical ECG pattern. Our study aimed to evaluate the role of a new HPL-treadmill exercise testing (TET) protocol in detecting Br1ECGp fluctuation compared to resting HPL-ECG. 74 out of 163 patients of a Brugada syndrome (BrS) Brazilian cohort (GenBra Registry) underwent exercise testing with HPL-TET protocol. Precordial leads were displayed in strategic positions in the right and left parasternal spaces. The step-by-step analysis included ECG classification (as presence or absence of Br1ECGp) in standard vs. HPL leads placement in the following sequences: resting phase, maximal exercise, and the passive recovery phase (including 'quick lay down'). For heart rate recovery (HRR) measurements and comparisons, a Student's t-test was applied. McNemar tests compared the detection of Br1ECGp. The significance level was defined as P < 0.05. Fifty-seven patients (57/74; 77%) were male, the mean age was 49.0 ± 14, 78.4% had spontaneous BrS, and the mean Shanghai score was 4.5. The HPL-TET protocol increased Br1ECGp detection by 32.4% against resting HPL-ECG (52.7% vs. 20.3%, P = 0.001) alone. Stress testing using HPL with the passive recovery phase in the supine position offers an opportunity to unmask the type 1 Br1ECGp, which could increase the diagnostic yield in this population.