Prescription of exercise to heart transplantation recipients: the role of respiratory rate.
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Adult↗
Biomedical subjects
David Ben-Sira
Publications and source records attributed to David Ben-Sira.
Beta-blockers, exercise, and the immune system in men with coronary artery disease.
PURPOSE: The purpose of the present study was to examine the effect of aerobic exercise training on the immune system in coronary artery disease patients treated with beta-blockers. METHODS: Twenty-five patients (46.1 +/- 2 yr) treated with atenolol, a beta-blocker agent, for 3 months before exercising were divided randomly into two groups: 15 underwent an aerobic exercise training program for 12 wk at 65-70% of their work capacity, whereas the other 10 patients served as controls. RESULTS: After training, levels of CD4 and CD8 cells were significantly (P < 0.05) higher and concomitantly the CD4/CD8 ratio decreased significantly (P < 0.05) in the exercising group compared with the control group. CONCLUSIONS: Data suggest that coronary artery disease patients exercising aerobically at 65-70% of their work capacity gain a statistically significant higher lymphocyte T cell function as compared with their untrained counterparts.
Adrenergic beta-Antagonists↗
Effect of changes in load carriage while walking on the left ventricular function in highly trained elderly subjects.
BACKGROUND: In previous studies, the effect of isometric stress on the dynamic performance of a graded exercise test in normal subjects augmented afterload and brought about changes in left ventricular function more often than did results from physical exercise. OBJECTIVE: This study used the metabolic charts and echocardiography to examine the influence of two different types of load carriage during 30 min of treadmill walking on left ventricular function, hemodynamics, and cardiovascular responses. METHODS: Fifteen elderly (age 66.1 +/- 3.5 years) aerobically well-trained male subjects (VO(2 peak) 44.2 +/- 5.0 ml x kg(-1) x min(-1)) volunteered in this study. The subjects walked on a treadmill (at a speed of 4.5 km x h(-1)), carrying a load of 20 kg during one session and a load of 30 kg during a second session. RESULTS: Following the 30-min exercise in each session, significant (p < 0.05) differences were noted between the 20-kg and the 30-kg work loads with regard to cardiac output (6.8 +/- 0.5 and 7.8 +/- 0.4 l.min(-1)), heart rate (114.0 +/- 11.0 and 126.0 +/- 10.0 beats.min(-1)), diastolic blood pressure (79.4 +/- 5.0 and 84.3 +/- 5.0 mm Hg, mean arterial blood pressure (104.0 +/- 4.0 and 109.2 +/- 3.0 mm Hg), and left ventricular contractility ratio (3.3 +/- 0.4 and 3.6 +/- 0.3). No significant differences were noted between the work loads with regard to systolic blood pressure, cardiac output, left ventricular volumes, and ejection fraction. CONCLUSIONS: This study suggests that in the highly trained elderly, the influence of the autoregulation mechanism dominates during combined dynamic and isometric exercises, thus the opposing force to the left ventricular ejection is reduced which in turn does not change left ventricular global function.
Aged↗
Left ventricular function at peak all-out anaerobic exercise in older men.
BACKGROUND: All-out anaerobic exercise may be dangerous for the older population, due to hypoxia and inappropriate blood pressure response. OBJECTIVES: This study compared and evaluated left ventricular function at peak all-out anaerobic effort in 12 well-trained older (58 +/- 1 years) and 12 young men (22 +/- 1 years). METHODS: Subjects were studied by echocardiography at peak all-out anaerobic exercise, on a cycle ergometer. RESULTS: Seven older subjects experienced ECG abnormalities. Significant (p < 0.05) differences between the older group and the young group, respectively, were noted for: cardiac output (9.8 +/- 0.9 and 15.8 +/- 0.9 l.min(-1)), left ventricular end-systolic pressure-volume ratio (4.7 +/- 0.8 and 4.4 +/- 4.9), left ventricular end-diastolic volume (104.8 +/- 6.9 and 125.7 +/- 6.2 ml), ejection fraction (67.1 +/- 6.0 and 59.8 +/- 5.5%), left ventricular end-systolic pressure volume ratio (4.4 +/- 0.4 and 4.8 +/- 0.3 ratio), and total peripheral resistance (966.0 +/- 84.0 and 660 +/- 82.8 dyn.s(-1).cm(-5)). CONCLUSIONS: Data suggest that during all-out anaerobic exercise, forces opposing ejection were not reduced enough to avoid left ventricular dysfunction and ECG abnormalities in the older subjects. This is attributed to functional changes with age in the myocardium and associated blood vessels, leading to impairment of left ventricular function and blunted inotropic and chronotropic responses to catecholamine. Therefore, an all-out anaerobic-type effort should not be given to an older subject due to the great hazardous potential.
Adult↗