Home About us Contact
|
Home About us Contact | ||
|
|
||
Exercise Duration (exercise + duration)
Selected AbstractsSelf glucose monitoring and physical exercise in diabetesDIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue S1 2009G. Pugliese Abstract Cardiorespiratory fitness, which is determined mainly by the level of physical activity, is inversely related to mortality in the general population as well as in subjects with diabetes, the incidence of which is also increased by low exercise capacity. Exercise is capable of promoting glucose utilization in normal subjects as well as in insulin-deficient or insulin-resistant diabetic individuals. In diabetic subjects treated with insulin or insulin secretagogues, exercise may also result in complications, with too much insulin causing hypoglycaemia and not enough insulin leading to hyperglycaemia and possibly ketoacidosis; both complications may also occur several hours after exercise. Therefore, self-monitoring of blood glucose before, during (for exercise duration of more than 1 h) and after physical exercise is highly recommended, and also carbohydrate supplementation may be required. In the Italian Diabetes Exercise Study (IDES), measurement of blood glucose and systolic and diastolic blood pressure levels before and after supervised sessions of combined (aerobic + resistance) exercise in type 2 diabetic subjects with the metabolic syndrome showed significant reductions of these parameters, though no major hypoglycaemic or hypotensive episode was detected. The extent of reduction of blood glucose was related to baseline values but not to energy expenditure and was higher in subjects treated with insulin than in those on diet or oral hypoglycaemic agents (OHA). Thus, supervised exercise training associated with blood glucose monitoring is an effective and safe intervention to decrease blood glucose levels in type 2 diabetic subjects. Copyright © 2009 John Wiley & Sons, Ltd. [source] Echocardiographic Doppler Evaluation of Left Ventricular Diastolic Filling in Older, Highly Trained Male Endurance AthletesECHOCARDIOGRAPHY, Issue 1 2000PETER R. JUNGBLUT M.D. Previously published data have suggested that endurance training does not retard the normative aging impairment of early left ventricular diastolic filling (LVDF). Those studies, suggesting no effect of exercise training, have not examined highly trained endurance athletes or their LVDF responses after exercise. We therefore compared LVDF characteristics in a group of older highly trained endurance athletes (n= 12, mean age 69 years, range 65,75) and a group of sedentary control subjects (n= 12, mean age 69 years, range 65,73) with no cardiovascular disease. For all subjects, M-mode and Doppler echocardiographic data were obtained at rest. After baseline studies, subjects underwent graded, maximal cardiopulmonary treadmill exercise testing using a modified Balke protocol. Breath-by-breath respiratory gas analysis and peak exercise oxygen consumption (VO2max) measurements were obtained. Immediately after exercise and at 3,6 minutes into recovery, repeat Doppler echocardiographic data were obtained for determination of LVDF parameters. VO2max (44 ± 6.3 vs 27 ± 4.2 mllkglmin, P< 0.001), oxygen consumption at anaerobic threshold (35 ± 5.4 vs 24 ± 3.8 mllkglmin, P< 0.001), exercise duration (24 ± 3 vs 12 ± 6 minutes, P< 0.001), and left ventricular mass index (61 ± 13 vs 51 ± 7.8 kglm2, P< 0.05) were greater in endurance athletes than in sedentary control subjects, whereas body mass index was lower (22 ± 1.7 vs 26 ± 3.4 kglm2, P< 0.001). No differences in any of the LVDF characteristics were observed between the groups with the exception of a trend toward a lower atrial filling fraction at rest in the endurance athlete group versus the control subjects (P= 0.07). High-intensity endurance exercise training promotes exceptional peak exercise oxygen consumption and cardiovascular stamina but does not appear to alter normative aging effects on left ventricular diastolic function. (ECHOCARDIOGRAPHY, Volume 17, January 2000) [source] DNA damage in peripheral blood leukocytes of physically active individuals as measured by the alkaline single cell gel electrophoresis assayENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 4 2009Gursatej Gandhi Abstract DNA damage induced by physical activity and/or exercise has been reported under different conditions but not for individuals maintaining physical fitness by regular strenuous exercise. Therefore, we compared levels of DNA damage in blood leukocytes of 40 healthy individuals (35 males, 5 females) who regularly exercised in gymnasiums/health clubs and 15 healthy sedentary controls who had never exercised. The former group was selected (after informed consent) on the basis of how long they had been exercising on a regular basis as well as their exercise schedule and regimen. The length of time since starting a regular exercise regimen ranged from 2 months to 9 years, whereas the daily exercise duration ranged from 40 min to 3 hrs and warm-up sessions ranged from none to 90 min. The length of DNA migration (44.66 ± 2.68 ,m in males, 29.62 ± 1.69 ,m in females) and the percentage of cells with tails (79.86 ±1.27% in males, 67.20 ± 0.96% in females) in peripheral blood leukocytes of physically active individuals were increased significantly (P < 0.001) with respect to corresponding values in control males and females (18.85 ± 1.79 ,m, 23.37 ± 3.94 ,m; 24.50 ± 1.98%, 33.00 ± 4.44%, respectively). Highly significant differences for DNA damage were also observed between physically active males and females. These observations, in the absence of any other exposures, indicate a correlation between strenuous exercise to keep fit and increased levels of DNA damage. This finding may have relevance in terms of the ageing process, with diseases associated with aging, and with carcinogenesis. Environ. Mal. Mutagen. 2009. © 2009 Wiley-Liss, Inc. [source] Endurance exercise is associated with increased plasma cardiac troponin I in horsesEQUINE VETERINARY JOURNAL, Issue S36 2006T. C. HOLBROOK Summary Reason for performing study: Information is lacking regarding the influence of long distance exercise on the systemic concentration of cardiac troponin I (cTnl) in horses. Objectives: To determine if the concentration of cTnl in horses competing in 80 and 160 km endurance races increases with exercise duration and if cTnl concentrations can be correlated with performance data. Methods: Blood samples for the measurement of cTnl and 3 min electrocardiogram recordings were obtained from horses prior to, during and after completion of 80 and 160 km endurance races at 3 ride sites during the 2004 and 2005 American Endurance Ride Conference competition seasons. Results: Full data sets were obtained from 100 of the 118 horses. Endurance exercise was associated with a significant increase in cTnl over baseline in both distance groups. Failure to finish competition (poor performance) was also associated with an increased cTnl concentration over baseline at the time of elimination when data from both distances were combined. Other than one horse that developed paroxysmal atrial fibrillation, no arrhythmias were noted on the 3 minute ECG recordings that were obtained after endurance exercise in either distance group. Conclusions: Systemic concentrations of cTnl increase in endurance horses competing in both 80 and 160 km distances. Although final cTnl concentrations were significantly increased over their baseline values in horses that failed to finish competition, the degree of increase was not greater than the increase over baseline seen in the horses that successfully completed competition. The clinical significance of increased cTnl in exercising horses could not be ascertained from the results of this study. Potential relevance: These data indicate that cardiac stress may occur in horses associated with endurance exercise. Future studies utilising echocardiograpy to assess cardiac function in horses with increased cTnl are warranted. [source] The Effects of Rate-Adaptive Atrial Pacing Versus Ventricular Backup Pacing on Exercise Capacity in Patients with Left Ventricular DysfunctionPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 1 2009M.S.C.E., ROD PASSMAN M.D. Background: Atrial rate-adaptive pacing may improve cardiopulmonary reserve in patients with left ventricular dysfunction. Methods: A randomized, blinded, single-crossover design enrolled dual-chamber implantable defibrillator recipients without pacing indications and an ejection fraction ,40% to undergo cardiopulmonary exercise treadmill stress testing in both atrial rate-adaptive pacing (AAIR) and ventricular demand pacing (VVI) pacing modes. The primary endpoint was change in peak oxygen consumption (VO2). Secondary endpoints were changes in anaerobic threshold, perceived exertion, exercise duration, and peak blood pressure. Results: Ten patients, nine males, eight with New York Heart Association class I, mean ejection fraction 24 ± 7%, were analyzed. Baseline VO2 was 3.6 ± 0.5 mL/kg/min. Heart rate at peak exercise was significantly higher during AAIR versus VVI pacing (142 ± 18 vs 130 ± 23 bpm; P = 0.05). However, there was no difference in peak VO2 (AAIR 23.7 ± 6.1 vs VVI 23.8 ± 6.3 mL/kg/min; P = 0.8), anaerobic threshold (AAIR 1.3 ± 0.3 vs VVI 1.2 ± 0.2 L/min; P = 0.11), rate of perceived exertion (AAIR 7.3 ± 1.5 vs VVI 7.8 ± 1.2; P = 0.46), exercise duration (AAIR 15 minutes, 46 seconds ± 2 minutes, 54 seconds vs VVI 16 minutes, 3 seconds ± 2 minutes, 48 seconds; P = 0.38), or peak systolic blood pressure (AAIR 155 ± 22 vs VVI 153 ± 21; P = 0.61) between the two pacing modes. Conclusion: In this study, AAIR pacing did not improve peak VO2, anaerobic threshold, rate of perceived exertion, or exercise duration compared to VVI backup pacing in patients with left ventricular dysfunction and no pacing indications. [source] AAIR Versus DDDR Pacing in the Bradycardia Tachycardia Syndrome: A Prospective, Randomized, Double-blind, Crossover TrialPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 11 2001BERNHARD SCHWAAB SCHWABB, B., et al.: AAIR Versus DDDR Pacing in the Bradycardia Tachycardia Syndrome: A Prospective, Randomized, Double-blind, Crossover Trial. In 19 patients paced and medicated for bradycardia tachycardia syndrome (BTS), AAIR and DDDR pacing were compared with regard to quality of life (QoL), atrial tachyarrhythmia (AFib), exercise tolerance, and left ventricular (LV) function. Patients had a PQ interval , 240 ms during sinus rhythm, no second or third degree AV block, no bundle branch block, or bifascicular block. In DDDR mode, AV delay was optimized using the aortic time velocity integral. After 3 months, QoL was assessed by questionnaires, patients were investigated by 24-hour Holter, cardiopulmonary exercise testing (CPX) was performed, and LV function was determined by echocardiography. QoL was similar in all dimensions, except dizziness, showing a significantly lower prevalence in AAIR mode. The incidence of AFib was 12 episodes in 2 patients with AAIR versus 22 episodes in 7 patients with DDDR pacing (P = 0.072). In AAIR mode, 164 events of second and third degree AV block were detected in 7 patients (37%) with pauses between 1 and 4 seconds. During CPX, exercise duration and work load were higher in AAIR than in DDDR mode (423 ± 127 vs 402 ± 102 s and 103 ± 31 vs 96 ± 27 Watt, P < 0.05). Oxygen consumption (VO2), was similar in both modes. During echocardiography, only deceleration of early diastolic flow velocity and early diastolic closure rate of the anterior mitral valve leaflet were higher in DDD than in AAI pacing (5.16 ± 1.35 vs 3.56 ± 0.95 m/s2 and 69.2 ± 23 vs 54.1 ± 26 mm/s, P < 0.05). As preferred pacing mode, 11 patients chose DDDR, 8 patients chose AAIR. Hence, AAIR and DDDR pacing seem to be equally effective in BTS patients. In view of a considerable rate of high degree AV block during AAIR pacing, DDDR mode should be preferred for safety reasons. [source] The repeatability of submaximal endurance exercise testing in cystic fibrosis,PEDIATRIC PULMONOLOGY, Issue 1 2007MB BCh BAO, Sinead C. Barry BSc Abstract Submaximal endurance cycle ergometer exercise tests are used to measure the efficacy of an exercise intervention, but the repeatability of these tests in patients with cystic fibrosis (CF) has not been established. The purpose of this study was to examine the repeatability of submaximal endurance testing in stable CF. Fifteen adults with CF underwent two submaximal endurance tests carried out over a 7-day period. A subset of six subjects returned 28 days later for a third submaximal endurance test. Workload was set at 80% of maximum workload and exercise was performed to exhaustion. Oxygen consumption, minute ventilation, tidal volume, carbon dioxide output, respiratory rate, heart rate, and oxygen saturation were measured at rest, at end exercise and at four matched times during the submaximal endurance tests (20, 40, 60, and 80% of exercise duration calculated from the first endurance test). Submaximal endurance test time was highly repeatable with no significant learning effect identified on multiple testing. Submaximal endurance exercise time demonstrated a variability of 5.7% which is consistent with high levels of repeatability. Metabolic, ventilatory and cardiac variables were all also highly reproducible between test days. Submaximal endurance testing is repeatable in stable CF, confirming that submaximal endurance tests are a reliable tool for assessment of therapeutic benefit in patients with CF. Pediatr Pulmonol. 2007; 42:75,82. © 2006 Wiley-Liss, Inc. [source] Chest pain is inversely associated with blood pressure during exercise among individuals being assessed for coronary heart diseasePSYCHOPHYSIOLOGY, Issue 2 2007Blaine Ditto Abstract Acute and chronic increases in blood pressure have been related to decreases in pain perception. This phenomenon has been studied primarily using acute experimental pain stimuli. To extend the literature to naturalistic pain and in particular the problem of silent cardiac ischemia, this study examined the relationship between blood pressure and chest pain during exercise stress testing. Nine hundred seven (425 men, 482 women) individuals undergoing exercise stress testing for diagnosis of possible myocardial ischemia completed the McGill Pain Questionnaire (MPQ) immediately afterward and other questionnaires before and after testing. Blood pressure was measured before, during, and after exercise. Systolic blood pressure at the end of exercise was inversely related to a number of measures of pain such as total score on the MPQ. The relationship could not be explained by individual differences in exercise duration, medication use, sex, or other measured variable. In sum, the inverse relationship between blood pressure and sensitivity to pain that has been observed in other populations in experimental and naturalistic conditions was observed for chest pain during exercise. Blood pressure may contribute to episodes of silent ischemia. [source] The effects of protective helmet use on physiology and cognition in young cricketersAPPLIED COGNITIVE PSYCHOLOGY, Issue 9 2004Nick Neave Many studies have reported physiological and cognitive decrements following heat stress. Of particular concern in cricket are the possible negative effects of sustained protective helmet use, as this leads to an increase in heat-related stress. Correct and rapid decision making, and focused attention are essential for efficient performance whilst batting, and it is possible that helmet usage could impair such processes. In a repeated-measures, randomized crossover study, physiological, self-report, and cognitive measures were taken from 16 teenage cricketers before and after moderately intense (batting) exercise. Participants underwent the assessments twice, once while wearing a standard protective helmet, and again, when not wearing a helmet (counterbalanced). While helmet use did not lead to significant physiological changes, wearing a helmet led to some cognitive impairments in attention, vigilance and reaction times. These preliminary findings could have significance for cognitively demanding sports (and perhaps military and industrial settings) in which participants perform cognitively demanding operations under conditions of physical exercise whilst wearing protective helmets. Additional factors of hydration, exercise duration, and helmet design are discussed. Copyright © 2004 John Wiley & Sons, Ltd. [source] A historical overview of enhanced external counterpulsationCLINICAL CARDIOLOGY, Issue S2 2002Anthony N. Demaria M.D., MACC Chief Abstract Angina remains a significant health problem in the United States and the world. Although there are a variety of pharmacologic and interventional therapies to treat angina, many patients are not adequately helped by these treatments. Enhanced external counterpulsation (EECP) is an effective, noninvasive technique designed to decrease the frequency and duration of anginal episodes, as well as increase exercise duration in patients with acute angina. Since the early 1960s, the technology of EECP has been thoroughly refined. In addition, a number of important clinical trials have provided evidence for its effectiveness. Continuing research is needed to determine the best patients for EECP and its appropriate clinical application. [source] Relationship between arterial baroreflex sensitivity and exercise capacity in patients with acute myocardial infarctionCLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 1 2010Fumio Yuasa Summary To investigate the relationship between arterial baroreflex sensitivity (BRS) and exercise capacity, we examined arterial BRS and its relation to exercise capacity during upright bicycle exercise in 40 uncomplicated patients with acute myocardial infarction. Arterial BRS was measured 3 weeks (20 ± 5 days) after acute myocardial infarction and assessed by calculating the regression line relating phenylephrine-induced increases in systolic blood pressure to the attendant changes in the R,R interval. All patients underwent graded symptom-limited bicycle exercise with direct measurements of hemodynamic and metabolic measurements. In all patients, the average arterial BRS was 5·6 ± 2·6 ms mmHg,1. There were no significant correlations between arterial BRS and hemodynamic measurements at rest. However, arterial BRS was negatively related to systemic vascular resistance at peak exercise (r = ,0·60, P = 0·0001) and percent change increase in systemic vascular resistance from rest to peak exercise (r = ,0·45, P = 0·003), whereas arterial BRS was positively related to cardiac output (r = ,0·48, P = 0·002) and stroke volume at peak exercise (r = 0·42, P = 0·007), and percent change increase in cardiac output (r = ,0·55, P = 0·0002) and stroke volume from rest to peak exercise (r = 0·41, P = 0·008). Furthermore, arterial BRS had modest but significant correlations with peak oxygen consumption (r = ,0·48, P = 0·002) and exercise duration (r = 0·35, P = 0·029), indicating that patients with better arterial BRS have better exercise capacity in patients with acute myocardial infarction. These results suggest that arterial BRS was linked to central and peripheral hemodynamic responses to exercise and hence, contributed to exercise capacity after acute myocardial infraction. [source] | |||||||||||||