Percent Of Heart Rate Reserve Research Articles

Investigating the Impact of Eight Weeks of Aerobic Training on Liver Enzymes and Hematological Profile in Children with Leukemia

Objectives: The objective of the evaluation was to study and determine the impact of eight weeks of aerobic training (AT) on liver enzymes and changes in hematological profile in children with leukemia.Methods: This is a semi-experimental and applied study. Statistical samples include 24 children aged 7 to 10 years that referred to hospital and were divided randomly into two control (n=12) and experimental (n=12) groups. Eight-week AT with 40 to 70 percent of heart rate reserve, three sessions per week, no exercise training program was observed in the controls during the study. We measure Liver enzymes such as Aspartate aminotransferase (AST) and alanine aminotransferase (ALT), Hemoglobin (Hb), White Blood Cells (WBC), platelets (PLT), and bilirubin. Data analysis using a paired t-test and analysis of covariance was performed with software SPSS version 20.Results: The results showed that moderate-intensity AT has a significant effect on hemoglobin and liver enzyme levels and a significant increase in Hb (p<0.05) and significant reduction the ALT and AST (p<0.05) whereas there was no significant influence on WBC, ALT, and bilirubin (p>0.05).Conclusion: AT may accelerate the oxygen supply and reduce liver damage caused by medications in children diagnosed with leukemia without having corrupting effect on PLT, bilirubin, and safety factors.

Physiological demands in simulated tennis matches and hitting tests take account of the translational and rotational kinetic energy ratio of the ball.

Assessment of fatigue effect on hitting ability in tennis has been controversial in previous studies. The purpose of this study was to determine the relationship between player fatigue and groundstroke type in tennis. We hypothesized that subjects with higher blood lactate concentration during play would apply heavier spin to the ball. We divided players into two groups based on their blood lactate concentration during a pre-measured hitting test (HIGH and LOW). Each group performed a simulated match-play protocol consisting of repeated running and hitting tests, which simulated a three-set match. Heart rate, percent of heart rate reserve, oxygen uptake, pulmonary ventilation, and respiratory exchange were measured. The distance between the ball's landing point and the target, and the ball's kinematics, were recorded during the hitting test between sets. We found no significant difference in ball kinetic energy between groups, but the HIGH group hit the ball with a greater ratio of rotational kinetic energy to total kinetic energy. However, the progression of the simulation protocol did not affect physiological responses (including blood lactate concentration) or hitting ability. Therefore, it is suggested that the type of groundstrokes used by players is one of the factors that should be considered when discussing fatigue in tennis.

Low chronotropic index predicts rehospitalization in post-acute myocardial infarction patients with preserved or mildly reduced left ventricular ejection fraction

Abstract Background There are limited data about the clinical utility of combined stress echocardiography and cardiopulmonary exercise testing (CPET-ESE) in predicting prognosis in patients after acute myocardial infarction (AMI) with preserved left ventricular ejection fraction (LVEF). Aim To assess prognostic parameters using CPET-ESE in post-AMI patients with preserved or mildly reduced LVEF. Methods Eighty-seven patients after the first AMI with LVEF >40% were followed for 2 years (median 1.93 years IQR 1.16–2.41). The composite end-point was all-cause mortality or rehospitalization due to ischaemic heart disease (AMI, unstable angina, percutaneous coronary intervention/coronary artery bypass grafting) or heart failure exacerbation. All patients underwent symptom-limited CPET-ESE on a semi-supine cycle ergometer 3 to 5 weeks after AMI. The chronotropic index was calculated as the percent of heart rate reserve. Six patients refused to complete the survey and they were not included in the analysis. Results Follow-up was conducted in 81 consecutive patients (mean age 59±10 years, 62% males, 50% AMI with ST-segment elevation, 85% on beta-blockers). Mean LVEF was 56±9% and peak VO2 18.5±5.0 mL/kg/min. There were no deaths during follow-up. The composite end-point occurred in 13 patients. In multivariate Cox regression analysis after correction for demographic and clinical variables, only chronotropic index correlated with the composite end-point (HR 0.93, 95% CI 0.87–0.99, p=0.026). A positive predictive value of 33.3% and a negative predictive value of 91.3% (sensitivity 61.5%, specificity 76.5%, area under the curve, AUC 71%) for predicting the composite end-point was established for the chronotropic index ≤36.8% (Fig. 1). There was a statistically significant difference in the composite end-point occurrence (p<0.01) between subgroups with the chronotropic index above and below that threshold (Fig. 2). Conclusions In patients after the first AMI with preserved or mildly reduced left ventricular systolic function, a lower chronotropic index is a predictor of rehospitalization in 2-year follow-up. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): Centre of Postgraduate Medical Education, Warsaw, Poland

Israel's first national remote cardiac rehabilitation program - patient response and potential factors affecting successful completion

Abstract Funding Acknowledgements Type of funding sources: Public hospital(s). Main funding source(s): Sheba Medical Center Introduction Cardiac rehabilitation is an essential program for the reduction of future cardiac events and improve quality of life. However, many vulnerable individuals do not achieve this desired outcome due to the restrictive nature of institution-based rehabilitation. With this in mind was developed the Remote Cardiac Rehabilitation Program (RCRP). Our aim was to create the optimal conditions so that our patients are guided and stimulated in order to successfully complete the program. Material and method This study involved 306 patients with established CHD who underwent a six-month RCRP, three months of which were subsidized by health insurance. RCRP involves regular exercise, monitored by a smart sports watch and transferred to both the medical operations center as well as the mobile application on the patient’s smartphone. We built models to get predictors for the best patient performance in the last (third) month. Predictions were made based on their performance in the first month and some demographical data. Age and gender were taken as base features to all the models. Results and discussion The study involved patients, 81.5% men, aged 57.59 (±10.62), who were admitted to the RCRP mainly after myocardial infarction or coronary interventions (49%). The median minutes per week that patients performed aerobic exercise was 164, a median of 92 minutes at target HR (established by exercise physiologist), and the median percent of heart rate reserve was 76 % across exercise training. The median number aerobic sessions per week was 4, while the median daily steps was 8,370. Values had no significant differences across the 24 weeks. Following the 24-weeks of intervention, there was a significant improvement in exercise capacity, assessed by estimated METS using pre and post exercise stress tests from 9.95±2.57 to 11.71±3.43 (p<0.001). The most significant predictors of program adherence were older age and the number of weekly aerobic minutes and sessions in the first weeks of training (p<0.005). There is a direct relationship between the patient's age and the program compliance - the older the patient, the higher the compliance. Conclusion Adherence and the performance achieved by patients in the RCRP is well within guideline recommendations, leading to a significant improvement in exercise capacity. Older age, as well as early program adherence were significant factors which led to better program completion.

Effects of Matched Intermittent and Continuous Exercise on Changes of Cardiac Biomarkers in Endurance Runners.

PurposeEndurance runners training with high-intensity intermittent exercise might experience damage to cardiac muscle. We have therefore compared changes of cardiac biomarkers after workload-matched intermittent and continuous exercise.MethodsTwelve endurance runners [11 males, 1 female; means ± SD O2max, 62.4 ± 5.4 ml kg–1 min–1; velocity of O2max (v O2max), 17.1 ± 1.4 km h–1] completed an intermittent and continuous exercise trial in random order. Intermittent exercise consisted of running at 90% vO2max for 2 min followed by 50% vO2max for 2 min, repeated for 92 min. Continuous exercise was performed at 70% vO2max for 92 min. Blood samples were drawn before and 0, 2, 4, 24, and 48 h after exercise for assay of various cardiac biomarkers. Changes in concentration of biomarkers were averaged for the comparison of intermittent with continuous exercise after adjustment for baseline concentration and exercise intensity expressed as percent of heart-rate reserve (%HRR); magnitudes were assessed by standardization.ResultsThere were moderate and large increases in high-sensitivity cardiac troponin-I and -T respectively following exercise. The differences between the increases adjusted to the mean intensity of 78 %HRR were trivial, but at 85 %HRR the increases for cardiac troponin-I and -T were moderately higher for intermittent compared with continuous exercise (factor difference, ×/÷90% confidence limits: 3.4, ×/÷1.9 and 2.1, ×/÷1.8 respectively). Differences in the changes in other cardiac biomarkers were trivial.ConclusionProlonged intermittent exercise is potentially more damaging to cardiac muscle than continuous exercise of the same average running speed at higher average heart rates in endurance runners.

Psychophysiological responses to Salsa dance.

Speculation exists whether dance provides physiological stimuli adequate to promote health and fitness benefits. Unfortunately, research to date has not addressed the affective and exertional responses to dance. These responses are of interest as positive affective and exertional responses experienced during physical activity may play an important role in predicting adherence. The present study aims to examine the psychophysiological responses of different Salsa dance styles. Ten pairs of dancers performed two different structured lessons of Salsa dance, including Typical Salsa and Rueda de Casino lessons, and a non-structured Salsa dance at a night club. Physiological responses (i.e., percent of heart rate reserve; %HRR) were continuously assessed and perceived exertion and affective valence were rated every 15 min throughout the trials. %HRR responses differed between the Salsa dance styles (%HRR from 41.3 to 51.9%), and participants were dancing at intensities near their ventilatory threshold. Specifically, Typical Salsa lesson elicited lower %HRR responses than Rueda de Casino lesson (p < 0.05), but similar %HRR responses to Salsa dance at a night club condition (p > 0.05). Surprisingly, exertional (from 8 to 11) and affective (from +3 to +5) responses were unaffected by Salsa dance styles (p > 0.05). These data support that different Salsa dance styles provide physiological stimuli adequate to promote health and fitness benefits, and perhaps more importantly, produce pleasurable experiences, which in turn might lead to an increase in adherence to Salsa dancing which likely provides exercise-like health benefits.

MEASUREMENT OF ENERGY EXPENDITURE WHILE PLAYING EXERGAMES AT A SELF-SELECTED INTENSITY.

Exergames have been suggested as a possible alternative to traditional exercise in the general population. The purpose of this study was to examine the heart rate (HR) and energy expenditure (EE) of young adults playing several different exergames, while self-selecting the component of the game to play and the intensity. A total of 117 participants, 18-35 years of age, were evaluated on one of four active video games. Participants were free to choose any component of the given game to play and they played at a self-selected intensity. The average HR and EE during the individual games were compared to resting conditions and to the American College of Sports Medicine (ACSM) guidelines. The HR and EE increased above resting conditions during each game (p<0.05). When the results of all games were combined, the HR was 125.4 ± 20.0 bpm and the average EE was 6.7 ± 2.1 kcal/min. This HR represents an average percent of heart rate reserve of 44.6 ± 14.1, high enough to be considered moderate intensity exercise. If performed for 30 minutes a day, five days per week, the average EE would be 1,005 kcals, enough to meet the ACSM recommendations for weekly EE. Therefore, at least some exergames could be a component of an exercise program.

여고생의 운동부하검사시 심폐기능과 심박수 회복에 대한 비만의 영향

The purpose of this study was to effect of obesity on cardiopulmonary functions and heart rate recovery at grade exercise test for high school girl`s. The subjects were composed of obese group(n=13) and normal group(n=14) in high school girl`s. Each groups completed an grades exercise test with Bruce protocol. Heart Rate Recovery(maximum heart rate-heart rate at recovery state) and the percent of heart rate reserve{(heart rate at recovery state-resting heart rate)/(measured maximum heart rate-resting heart rate)×100} were evaluated during three minutes after maximum exercise. The results were as follows: First, in the cardiopulmonary function, VO2max were significantly lower older obese group than normal group. HRrest were significantly higher older obese group than normal group. HRmax were significantly higher older obese group than normal group. Second, Heart rate recovery response in 1min, 2min and 3min after grades exercise test were significantly lower older obese group than normal group. %Heart rate recovery were not significantly different between obese group and normal group. In conclusion, obese group was lower compared to normal group in cardiovascular function. Also, in after grades exercise test show that delayed heart rate recovery.

Evaluation of heart rate as a method for assessing moderate intensity physical activity.

To further develop our understanding of the relationship between habitual physical activity and health, research studies require a method of assessment that is objective, accurate, and noninvasive. Heart rate (HR) monitoring represents a promising tool for measurement because it is a physiological parameter that correlates well with energy expenditure (EE). However, one of the limitations of HR monitoring is that training state and individual HR characteristics can affect the HR-VO2 relationship. The primary purpose of this study was to examine the relationship between HR (beats x min(-1)) and VO2 (mL x kg(-1 x -1) min(-1)) during field- and laboratory-based moderate-intensity activities. In addition, we examined the validity of estimating EE from HR after adjusting for age and fitness. This was done by expressing the data as a percent of heart rate reserve (%HRR) and percent of VO2 reserve (%VO2R). Sixty-one adults (18-74 yr) performed physical tasks in both a laboratory and field setting. HR and VO2 were measured continuously during the 15-min tasks. Mean values over min 5-15 were used to perform linear regression analysis on HR versus VO2. HR data were then used to predict EE (METs), using age-predicted HRmax and estimated VO2max. The correlation between HR and VO2 was r = 0.68, with HR accounting for 47% of the variability in VO2. After adjusting for age and fitness level, HR was an accurate predictor of EE (r = 0.87, SEE = 0.76 METs). This method of analyzing HR data could allow researchers to more accurately quantify physical activity in free-living individuals.