ISSN:0883-9212    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

The effects of dynamic exercise training on hemodynamic and catecholamine responses to rest, and to exercise and localized cold (singly and in combination) were studied in patients with coronary artery disease. Patients receiving beta-blocking medications and those not receiving beta blockers responded similarly. Myocardial oxygen demand (MVO2) was estimated by the rate-pressure product. Training caused a 25% increase in maximal oxygen uptake; a 15% decrease in resting MVO2; a decrease in MVO2during acute localized cold exposure alone (16%), in standard submaximal exercise alone (16%), or in the two in combination (19%); and unaltered resting and relative exercise urinary catecholamine excretions, although absolute exercise intensity had nearly doubled. We suggest that this reduction in MVO2may contribute to clinical improvement in patients with cardiac disease who engage in physical activity in cold environments.

ISSN:0883-9212    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

Twenty-six normolipidemic, nondiabetic patients with mild-to-moderate essential hypertension completed a 24-week, randomized, double-blind study to assess the long-term effects of hydrochlorothiazide (HCTZ), propranolol, and atenolol on lipid and carbohydrate metabolism. After a four-week, single-blind, placebo run-in, treatment began with an eight-week dose-titration period, followed by 16 weeks of treatment at a minimum effective dosage of HCTZ (25 or 50 mg bid), propranolol (40, 80, or 160 mg bid), or atenolol (50 or 100 mg once daily). After 12 and 24 weeks of active treatment, patients' serum lipid fractions and oral glucose tolerance were assessed for comparison with placebo baseline. At 24 weeks, propranolol and HCTZ produced a significant increase (P < .05) from baseline values for serum total triglycerides and very-low-density lipoprotein (VLDL). These increases were significant (P < .05) when compared with the reduction in levels of triglycerides and VLDL in the atenolol-treated group. Hydrochlorothiazide produced clinically significant increases in total area under curve for glucose tolerance, whereas atenolol did not. All three treatments produced significant decreases (P < .05) in blood pressure. Adverse effects were predominantly mild; there were no serious side effects among the three groups. This long-term study demonstrates that atenolol had no effect upon lipid or carbohydrate metabolism in contrast to propranolol or to HCTZ. These findings suggest an advantage for the use of atenolol if iatrogenic metabolic effects are shown to be clinically significant.

ISSN:0883-9212    

出版商:OVID    

年代:1988

数据来源: OVID

ISSN:0883-9212    

出版商:OVID    

年代:1988

数据来源: OVID

ISSN:0883-9212    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

We evaluated the effect of added weight load on exercise oxygen consumption (VO2) and heart rate (HR) in 13 cardiac rehabilitation patients (age 66, VO2max = 27 mL/kg/min). Each patient walked on a treadmill at S mph and 0 % grade in eight-minute stages without added weight and with added backpack weight-load increments of 5 kg until a previously determined training HR (THR) or 20-kg weight load was achieved. Oxygen consumption, HR, blood pressure, and rated perceived exertion, increased significantly at each level. The increases in VO2and HR with added weight were not related to initial body weight. Two patients achieved established THR at 15 kg and six patients achieved THR at 20 kg. The remaining five patients reached a mean of 87 % of desired THR. No ischemic electrocardiogram changes or dysrhythmias were observed. We conclude that weight-loaded walking (15–20 kg\ may be used as an alternate method of exercise training in patients who require a training VO2 in the range of 12.0–16.0 mL/kg/min.

ISSN:0883-9212    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

Serum potassium levels, catecholamines, and plasma renin activity are elevated during maximal dynamic exercise. Catecholamines and plasma renin activity have been shown to rise nonlinearly during exercise and to parallel changes in venous blood lactate. Since the hyperkalemia of exercise is modulated by catecholamines, we studied the changes in serum potassium in relation to attaining the exercise intensity associated with a rise in blood lactate (the lactate threshold). Eight healthy male subjects 25 to SO years of age underwent progressive cycle ergometry (PE) at increments of 25 W/4 min. During PE, absolute levels of peripheral venous potassium increased significantly only after the lactate threshold was exceeded (T < .01). In a control study (TC), subjects exercised to their lactate threshold and remained at that work rate for a time equal to that of PE. During TC, there were no significant increases in potassium until the final four minutes of exercise (T < .05). Plasma aldosterone levels rose comparably during PE and TC. These results demonstrate that significant potassium elevation during dynamic exercise begins at the lactate threshold. This threshold response of potassium may have clinical implications for exercise prescription in patients with impaired potassium homeostasis.

ISSN:0883-9212    

出版商:OVID    

年代:1988

数据来源: OVID

ISSN:0883-9212    

出版商:OVID    

年代:1988

数据来源: OVID

ISSN:0883-9212    

出版商:OVID    

年代:1988

数据来源: OVID