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At least 649 records · Page 36Linked to original sources
PubMed1979

The effect of beta-adrenoceptor blockade on factors affecting exercise tolerance in normal man.

1 We have studied the effects of single oral doses of 80 mg propranolol and 100 mg metoprolol on the cardiovascular and respiratory responses to progressive exercise in nine healthy men in double-blind, placebo-controlled experiment. As judged by their effects on exercise heart rate and cardiac output the doses of the two drugs used were equivalent. 2 Beta-adrenoceptor blockade reduced oxygen consumption by 3.5% over the whole work range with an increase in the respiratory exchange ratio of 0.056 units. Carbon dioxide production and exercise ventilation were unchanged. The two drugs had similar effects. Possible mechanisms for these observations are discussed. 3 Perceived exertion during exercise was increased by both the beta-adrenoceptor blocking drugs and this may be of relevance to the symptom of fatigue reported by patients on these drugs. Endurance, assessed as either total work done or maximal work achieved, was reduced by 15%.

Adrenergic beta-Antagonists↗
PubMed1977

Influence of short-term physical training on exercise tolerance after myocardial infarction.

14 patients with stabilized myocardial infarction were submitted to a functional evaluation before and after 3 sessions of interval training on the bicycle ergometer. With submaximal exercise, myocardial load decreases after short-term training, the heart rate and the blood pressure--heart rate product being significantly lower for the same oxygen consumption. Maximal working capacity, expressed in watts or oxygen consumption, increases significantly after short-term training, the benefit being one-third of that obtained after 6 weeks' training. These early changes in functional capacity are positively correlated with those obtained by a more prolonged rehabilitation program. Leg muscular blood flow during submaximal and maximal exercise tends to increase after short-term training, although this change is not systematic and thus not significant.

Adult↗
PubMed1989

Exercise tolerance in the heat on low and normal salt intakes.

1. Salt restriction is recommended in the treatment of hypertension and is included in national dietary guidelines, but its effect on exercise in hot conditions has not been extensively studied. 2. The effects of 2 weeks on two levels of salt intake (50 and 150 mmol/day) on the ability to exercise (60% of maximal oxygen uptake) in a hot environment (35 degrees C) were studied in eight healthy normotensive subjects. 3. All subjects were able to complete the exercise load on the two levels of salt intake. No differences in mean oxygen uptake, heart rate or rectal temperature during exercise were observed between the two salt intakes. 4. Plasma sodium, potassium and osmolality were similar on the two salt intakes both before and during exercise. Plasma renin activity and aldosterone concentration were elevated after 2 weeks on the reduced salt intake and remained so during exercise. 5. The estimated sweat rate during exercise was similar on the two salt intakes but the loss of sodium was less on the low salt intake. 6. On the basis of these results it is concluded that moderate salt restriction does not impair the ability to exercise in a hot environment.

Adult↗
PubMed1977

Increased exercise tolerance with nitrates in beta-blockaded patients with angina.

In 14 beta-blockaded anginal subjects, 10 of whom had poor left ventricular function, sublingual isosorbide dinitrate significantly increased maximal exercise capacity on a standardized multistage treadmill test. This was associated with changes in heart rate and blood pressure suggestive of a fall in left ventricular work. The effect of isosorbide lasts for at least two hours and when taken before exercise may be a useful addition to beta-blockade in patients with angina.

Adrenergic beta-Antagonists↗
PubMed1999

[Effect of specific inspiratory muscle training on dyspnea and exercise tolerance in congestive heart failure].

It has been shown that the inspiratory muscles of patients with congestive heart failure (CHF) are weaker than normal. This weakness may contribute to dyspnea and limit exercise capacity. But respiratory muscles can be trained for increase in both strength and endurance. This study was designed to evaluate the effect of specific inspiratory muscle training (SIMT) on muscular performance, lung function, dyspnea and exercise capacity in moderate heart failure. 10 patients with CHF (NYHA functional class II-III) received 1/2 hour of SIMT daily, 6 times/week, for 3 months. They started breathing at a resistance 15% of their Pimax for 1 week and the resistance was then increased incrementally to 60%. Spirometry, inspiratory muscle strength and endurance, and the 12-minute walk test were performed before and after the training period. All showed an increase in inspiratory muscle strength and endurance. This was associated with a small but significant increase in FVC, a significant increase in the distance walked (458 +/- 29 to 562 +/- 32 m, p < 0.01), and improvement in the dyspnea index score. SIMT resulted in increased inspiratory muscle strength and endurance. This increase was associated with decreased dyspnea and an increase in submaximal exercise capacity. SIMT may prove to be useful complementary therapy in CHF.

Aged↗
PubMed1983

Effect of nitroglycerin ointment (Nitrong) on exercise tolerance and several circulatory parameters in patients with angina pectoris.

Nine patients with coronary heart disease, 8 of whom were taking adrenergic beta-blockers, were tested by dynamic (bicycle) and isometric (sitting handgrip) exercise before and 2 and 6 h after application of nitroglycerin 30 mg in an ointment, or a matching placebo ointment, over 225 cm2 surface on the chest, in a double-blind, cross-over, single dose study. Exercise time until stopping from chest pain was significantly increased (by about 20%) by active ointment, and electrocardiographic ST-depression and chest pain intensity were significantly less pronounced during exercise both 2 and 6 h after application. During seated rest, active ointment also produced a significantly lower systolic blood pressure and a significantly higher heart rate at both 2 and 6 h, whereas during handgrip, significant differences from placebo were seen only at 2 h. All patients experienced headache for at least the 6 h of the study. At a given heart rate, ST-depression was less pronounced with active ointment than with placebo.

Aged↗
PubMed1986

Effects of aerobic training on exercise tolerance and echocardiographic dimensions in untrained postmenopausal women.

The cardiovascular effects of physical training were evaluated in a controlled trial involving 32 healthy, untrained, postmenopausal women. The subjects were randomly assigned to an aerobic exercise training program or a control group. The exercise group participated in at least three 40-minute supervised sessions per week for 8 months. Twenty-five subjects completed the study: eight in the control group and 17 in the training group. The training group had a significant increase over the training period in maximal oxygen consumption (27.3 +/- 4.6 ml/kg/min vs 30.8 +/- 5.4 ml/kg/min, p less than 0.05) and maximal treadmill exercise duration (9.8 +/- 2.6 minutes vs 11.3 +/- 2.2 minutes; p less than 0.05). The control group had no significant change in maximal treadmill exercise duration (9.0 +/- 1.2 minutes vs 9.2 +/- 1.4 minutes) but had a slight increase in maximal oxygen consumption (23.7 +/- 3.4 ml/kg/min vs 24.4 +/- 4.1 ml/kg/min, p less than 0.05). The training group had significant increases in M-mode echocardiographic left ventricular end-diastolic dimension (4.6 +/- 0.6 cm vs 4.8 +/- 0.4 cm, p less than 0.05) and calculated left ventricular ejection fraction (0.66 +/- 0.14 vs 0.74 +/- 0.12, p less than 0.05). M-mode echocardiograms demonstrated no significant change in left ventricular dimensions or wall thickness in the control group. In this group of untrained postmenopausal women, a training effect was associated with enhanced resting left ventricular ejection fraction and increased resting left ventricular end-diastolic dimension.

Adaptation, Physiological↗
PubMed1998

Improvement in exercise tolerance in isovaleric acidaemia with L-carnitine therapy.

The effect of 4 weeks' treatment with oral-L-carnitine (100 mg/kg per day) on carnitine status and metabolic parameters during an incremental ramp exercise test in a 12-year-old girl with isovaleric acidaemia was examined to determine its possible therapeutic role. The maximum work rate achieved increased from 110 to 120 watts; oxygen consumption at anaerobic threshold from 600 to 800 L/min; peak oxygen consumption from 1270 to 1450 L/min; and oxygen pulse, a measure of cardiac output, from 7.0 to 8.1 L/beat. These changes were associated with increases in plasma and urinary free and acyl carnitine concentrations but no change in physical activity. This observed effect of L-carnitine on exercise performance may be on cardiac or skeletal muscle function or both. We conclude that, in this single patient with isovaleric acid-aemia, L-carnitine supplementation had objective benefits and further studies on more patients are warranted.

Amino Acid Metabolism, Inborn Errors↗