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Maximal Heart Rate (maximal + heart_rate)
Selected AbstractsTen-Year Echo/Doppler Determination of the Benefits of Aerobic Exercise after the Age of 65 YearsECHOCARDIOGRAPHY, Issue 1 2010Alexander J. Muster M.D. As the human lifespan becomes progressively extended, potential health-related effects of intense aerobic exercise after age 65 need evaluation. This study evaluates the cardiovascular (CV), pulmonary, and metabolic effects of competitive distance running on age-related deterioration in men between 69 (±3) and 77 (±2) years (mean ± SD). Twelve elderly competitive distance runners (ER) underwent oxygen consumption and echo/Doppler treadmill stress testing (Balke protocol) for up to 10 years. Twelve age-matched sedentary controls (SC) with no history of CV disease were similarly tested and the results compared for the initial three series of the study. CV data clearly separated the ER from SC. At entry, resting and maximal heart rate, systolic/diastolic blood pressure, peak oxygen consumption (VO2max), and E/A ratio of mitral inflow were better in the ER (P < 0.05 vs. SC). With aging, ER had a less deterioration of multiple health parameters. Exceptions were VO2max and left ventricular diastolic function (E/A, AFF, IVRT) that decreased (P < 0.05, Year 10 vs. Year 1). Health advantages of high-level aerobic exercise were demonstrated in the ER when compared to SC. Importantly, data collected in ER over 10 years confirm the benefit of intensive exercise for slowing several negative effects of aging. However, the normative drop of exercise capacity in the seventh and eighth decades reduces the potential athleticism plays in prevention of CV events. (Echocardiography 2010;27:5-10) [source] Retrospective study of predictive variables for maximal heart rate (HRmax) in horses undergoing strenuous treadmill exerciseEQUINE VETERINARY JOURNAL, Issue S36 2006T. L. VINCENT Summary Reasons for performing study: Heart rate is one of the most commonly measured variables in equine exercise physiology and relative exercise intensity commonly expressed as % of maximal heart rate. A number of influences affect maximal heart rate (HRmax), including age of the horse but other factors have not been described. Objectives: To determine if fitness, health status, gender, breed, athletic use, body mass, in addition to age, are predictive of HRmax in the horse. Methods: Maximal heart rate data from 328 horses which underwent treadmill exercise tests at 5 different laboratories were obtained retrospectively. Univariable linear regression analyses were performed on individual variables. Multiple linear regression analysis using a backward elimination modelling procedure was then used to relate the observed HRmax values simultaneously with different predictive variables. Variables were retained in the final regression model if they or any of their categories were significantly predictive of HRmax at P<0.05 and if there was a significant collective contribution to the model from inclusion of each variable, also at P<0.05. Results: Age, fitness status, laboratory, gender and breed/use (combined category) were all statistically significantly predictive of HRmax. Together these variables accounted for 41% of the variance in HRmax. Age alone accounted for only ,13% of the variation between horses in HRmax. Neither body mass nor health status were significantly predictive. Conclusions: HRmax in the horse declines with age but is also influenced by other factors. As the factors investigated accounted for only 41% of the variation between horses, other unidentified variables with a strong influence on HRmax remain to be identified. Potential relevance: Factors such as fitness, age, gender, breed and use need to be considered when interpreting estimates or measurements of HRmax. [source] Clenbuterol administration does not attenuate the exercise-induced pulmonary arterial, capillary or venous hypertension in strenuously exercising Thoroughbred horsesEQUINE VETERINARY JOURNAL, Issue 6 2000M. MANOHAR Summary The present study was carried out to ascertain whether ,2 -adrenergic receptor stimulation with clenbuterol would attenuate the pulmonary arterial, capillary and venous hypertension in horses performing high-intensity exercise and, in turn, modify the occurrence of exercise-induced pulmonary haemorrhage (EIPH). Experiments were carried out on 6 healthy, sound, exercise-trained Thoroughbred horses. All horses were studied in the control (no medications) and the clenbuterol (0.8 ,g/kg bwt, i.v.) treatments. The sequence of these treatments was randomised for every horse, and 7 days were allowed between them. Using catheter-tip-transducers whose in-vivo signals were referenced at the point of the left shoulder, right heart/pulmonary vascular pressures were determined at rest, sub-maximal exercise and during galloping at 14.2 m/s on a 3.5% uphill grade - a workload that elicited maximal heart rate and induced EIPH in all horses. In the control experiments, incremental exercise resulted in progressive significant increments in right atrial as well as pulmonary arterial, capillary and venous (wedge) pressures and all horses experienced EIPH. Clenbuterol administration to standing horses caused tachycardia, but significant changes in mean right atrial or pulmonary vascular pressures were not observed. During exercise performed after clenbuterol administration, heart rate as well as right atrial and pulmonary arterial, capillary and wedge pressures also increased progressively with increasing work intensity. However, these values were not found to be statistically significantly different from corresponding data in the control study and the incidence of EIPH remained unaffected. Since clenbuterol administration also does not affect the transpulmonary pressure during exercise, it is unlikely that the transmural force exerted onto the blood-gas barrier of exercising horses is altered following i.v. clenbuterol administration at the recommended dosage. [source] Usefulness of a program of hospital-supervised physical training in patients with cystic fibrosisPEDIATRIC PULMONOLOGY, Issue 2 2004Attilio Turchetta MD Abstract Exercise is an important part of normal childhood, but the ability to exercise may be impaired in chronic lung diseases such as cystic fibrosis (CF). Improving exercise performance by training is very attractive. The aim of the present study was the evaluation of the effects of a physical aerobic training program, performed in the Children's Hospital and Research Institute "Bambino Gesł" (Rome, Italy) in outpatient CF children, supervised by a physician. Twelve patients (mean forced expiratory flow in 1 sec (FEV1), 71%), age range 12,24 years (16.7 ± 4.4 years), were enrolled. They performed a maximal exercise stress test on the treadmill (modified Bruce protocol) with breath-by-breath determination of oxygen consumption (VO2) to maximum at end-exercise; we measured time of exercise (TE), maximal heart rate (Hrmax) in beats per minute (bpm), and maximal systolic blood pressure (SBPm) in mmHg. The program consisted of 12 weeks of training twice a week. Each training session consisted of walking or running on the treadmill for 30 min at the speed that allowed the child to attain 60% of the maximal heart rate obtained during a baseline stress test for 4 weeks, 70% in the following 4 weeks, and 80% in the last 4 weeks, under strict medical supervision. HR was continously monitored. There was no change in FEV1 and forced vital capacity after the treatment period. Hrmax and SBPm also remained the same (P,=,0.37 and P,=,0.25, respectively). There was a significant increase in TE (P,<,0.002), VO2, VO2/kg, and pulmonary ventilation (VE) (P,<,0.0001, P,<,0.001, and P,<,0.001, respectively). This pilot study showed that a simple training program improves short-term cardiopulmonary fitness in children with CF. Further studies with a larger sample and for a more prolonged time are necessary to assess if sport can have a long-term effect on lung function or survival in CF patients. Pediatr Pulmonol. 2004; 38:115,118. © 2004 Wiley-Liss, Inc. [source] Composition of alveolar surfactant changes with training in humansRESPIROLOGY, Issue 3 2000Ian R. Doyle Objective: We test the hypothesis that the changes we observed previously in the relative amounts of disaturated phospholipids (DSP), cholesterol (CHOL), and surfactant protein-A (SP-A) in human alveolar surfactant in response to acute exercise, and which were related to fitness, can be induced by training. Methodology: We examine the effect of 7 weeks' training on these major surfactant components, together with surfactant protein-B (SP-B), in bronchoalveolar lavage fluid harvested from 17 males, both at rest and after acute exercise. Fitness was assessed as workload/heart rate achieved during cycling for 30 min at 90% of theoretical maximal heart rate, and was increased in all subjects following training (mean increase 22.2 ± 3.91%; P = 0.001). Results: Training significantly increased the SP-A/DSP, SP-B/DSP, SP-A/CHOL and SP-A/SP-B ratios in whole surfactant harvested from subjects both at rest and immediately following exercise. Training also increased the SP-B/CHOL ratio at rest. Changes were particularly marked at rest in the SP-A/DSP, SP-A/CHOL, and SP-B/CHOL ratios in the tubular myelin-rich fraction, and after exercise in the SP-A/DSP, SP-A/CHOL, and SP-A/SP-B ratios in the tubular myelin-poor fraction. Conclusion: We conclude that training markedly alters the composition of alveolar surfactant both at rest and with exercise; the physiological significance of these changes remains to be determined. [source] Correlation between 6-min walk test and exercise stress test in healthy childrenACTA PAEDIATRICA, Issue 3 2010A Limsuwan Abstract Aim:, To investigate the correlation between 6-min walk test (SMWT) and incremental treadmill exercise stress test (EST) as indicators for the functional capacity in children. Methods:, Healthy children aged 9,12 years were included. The anthropometric data, SMWT and EST were prospectively measured using the standard protocols. Various parameters were analysed to define the correlation between SMWT and EST. Results:, A total of 100 subjects (53 boys) aged 10.3 ± 1.0 years participated in the study. The SMWT distance was 586.1 ± 44.0 m. Height (r = 0.59, R2 = 35%), length of the leg (r = 0.64, R2 = 41%), heart rate at the end of SMWT (r = 0.59, R2 = 35%) and heart rate difference at the end of SMWT (r = 0.71, R2 = 50%) were found to have significant correlation with SMWT distance. The estimated maximal oxygen consumption (eVO2) obtained during the EST tended to be greater in boys than in girls. Among the parameters obtained during EST, maximal heart rate (r = 0.33, R2 = 11%) and the eVO2 (r = 0.54, R2 = 53%) were found to have significant correlation with SMWT. Conclusions:, SMWT distance is significantly correlated with the eVO2 obtained during the EST. This indicates that SMWT is also one of the predictive markers for EST performance. [source] Changes of QT dispersion in patients with coronary artery disease dependent on different methods of stress inductionCLINICAL CARDIOLOGY, Issue 3 2000B. Hailer M.D. Abstract Background: Episodes of stress-induced myocardial ischemia in patients with coronary artery disease (CAD) may cause increases of QT dispersion (QTd). Hypothesis: Aim of this study was to analyze the effect of increasing heart rates on QTd and to compare the effect of different methods of stress induction in patients with varying degrees of CAD when estimating QTd. Methods: We studied 58 patients, 22 with prior myocardial infarction (MI), 25 without MI or wall motion disturbances at rest, and 11 patients without evidence of CAD. Prior to coronary angiography, standard 12-lead ECGs were obtained at rest as well as during dynamic exercise and pharmacologic stress using arbutamine simultaneously with echocardiography. QTd was determined at each stress level by subtracting minimal from maximal QT interval duration. Results: QTd values at rest were not consistently higher in the patients with CAD. At maximal heart rate, QTd was statistically significantly higher in patients with CAD with a better discrimination between groups for pharmacologic stress (p < 0.005 for exercise, p < 0.0001 for arbutamine). Patients after MI had higher QTd values under all conditions than did the groups without MI. As in patients with CAD, the values of this group changed more radically as a result of pharmacologic stress. Conclusion: Patients with CAD can be identified on the basis of QTd under stress. These changes were not as marked in patients with MI as their rest values were already increased. Overall, drug-induced stress produced greater differences than dynamic exercise, suggesting that the ischemic threshold might be lower in the former. [source] Comparison of girth materials, girth tensions and their effects on performance in racehorsesAUSTRALIAN VETERINARY JOURNAL, Issue 1-2 2005J BOWERS Objective To compare the effect of girth materials and commonly used girth tensions on athletic performance of racehorses and to test the length tension properties of commercially available girths. Procedure Seven horses were exercised at speeds to produce 95% of maximal heart rates on 15 occasions using a randomised block design, and girthed with 5 different girths at 3 nominal tensions of 6, 12 or 18 kg. The girths used were a standard elastic race girth, an ,American' elastic race girth, an elastic race girth twice the normal width, a standard canvas race girth and a canvas race girth at twice the normal width. Tension in the girth was recorded continuously using an in-line load cell connected to a physiograph. Horses ran to fatigue on a treadmill inclined at 10% slope. Tensions were measured at peak inhalation (T/inh) and exhalation (T/exh), recorded at rest (rest) and during exercise (ex). An analysis of variance was used to compare the mean run to fatigue times (RTFT) between girth types and tensions, multiple pair-wise comparisons were then carried out using Tukey's test where significant differences were found. The length-tension relationships of five commercially available girths for training and racing of Thoroughbred racehorses were studied by the application of standardized weights in series to multiple samples of each type of girth. Measurements were taken in a controlled environment and analysis of variance was used to compare the means for length-tension of each girth type. Results The elastic and the ,American' elastic girths produced significantly longer RTFT when compared to the standard canvas girth (P=0.01 and P = 0.001 respectively). Also girths tensioned at Texhrest 6 kg and Texhrest 12 kg produced significantly longer RTFT than when girthed at Texhrest 18 kg (P=0.03 and P = 0.08 respectively). There were significant differences between the commercially available girth types at each tension (P < 0.05), but differences were not significant between girths of the same type. Girths with an elastic component reached their peak for maximum extension at 14.5 kg and thereafter their extension declined. Conclusion The type of girth and the tension at which it is applied affects athletic performance. Lower girth tensions and the use of elastic materials in the girth would appear to optimise performance. However according to this study and our previous study, none of the commercially available girths studied would adequately protect against the potentially detrimental effects of overtightening on athletic performance. [source] | |||||||||||||||||||