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PubMed1993

Influence of posture on arm exercise tolerance and physiologic responses in persons with spinal cord injured paraplegia.

This study compared metabolic and cardiopulmonary responses to incremental supine and upright sitting arm crank ergometry (ACE) in nine men with spinal cord injured paraplegia ranging from T1-T5. Both tests consisted of continuous graded ACE from rest to volitional fatigue on a modified electronically braked cycle ergometer with the work rate increased by 8.2 W.min-1. No significant differences (P > 0.05) existed for peak ACE power output (W), oxygen uptake, pulmonary ventilation, respiratory exchange ratio, and O2 pulse between the two tests. Heart rate and O2 pulse responses at six submaximal work rates representing 0-58% peak W were also not significantly different between postures. These data indicate that ACE tolerance in persons with high-lesion paraplegia was not enhanced when ACE was performed in the supine posture.

Adult↗
PubMed1989

Exercise tolerance and effects of training in young patients with cystic fibrosis and mild airway obstruction.

We evaluated the effects of an 8-week aerobic training (1 hr, three times a week) on physical performance of ten patients with cystic fibrosis (CF) (median age, 12.5 yr; range 11.1-15.3 yr), with mild airway obstruction (FEV1 = 77 +/- 22% pred.), and ten healthy age-matched children (CONTR) (median age, 12.7 yr; range 12.2-15.2 yr). Physical performance was tested with maximal incremental (MAX) and submaximal (SMAX) (fixed workload of 1.7 W/kg during 6 min) exercise tests on a cycle ergometer. These and standard spirometric and anthropometric measurements were performed at the beginning and end of a period with usual daily activity and one with the training program. The kinetics of ventilatory parameters at the onset and end of SMAX were displayed by fitting data on oxygen uptake and minute ventilation by monoexponential curves (least-squares method). At the start and the end of the training period, all children were timed for endurance run to voluntary exhaustion and for sprinting through an obstacle course. A pattern of relative hyperventilation during SMAX and of poor performance in endurance and obstacle runs were evident at the start of the training period in patients with CF. The effects of training on MAX and SMAX were small and partial; the improvement in field test performances was significant only for CF and could be attributed to improvement of skill and motivation.

Adolescent↗
PubMed1998

Ventilatory efficiency and exercise tolerance in 101 healthy volunteers.

The ventilatory equivalent for CO2 defines ventilatory efficiency largely independent of metabolism. An impairment of ventilatory efficiency may be caused by an increase in either anatomical or physiological dead space, the latter being the most important mechanism in the hyperpnoea of heart failure, pulmonary embolism, pulmonary hypertension and the former in restrictive lung disease. However, normal values for ventilatory efficiency have not yet been established. We investigated 101 (56 men) healthy volunteers, aged 16-75 years, measuring ventilation and gas exchange at rest (n = 64) and on exercise (modified Naughton protocol, n = 101). Age and sex dependent normal values for ventilatory efficiency at rest defined as the ratio ventilation:carbon dioxide output (VE:VCO2), exercise ventilatory efficiency during exercise, defined as the slope of the linear relationship between ventilation and carbon dioxide output (VE vs VCO2 slope), oxygen uptake at the anaerobic threshold and at maximum (VO2AT, VO2max, respectively) and breathing reserve were established. Ventilatory efficiency at rest was largely independent of age, but was smaller in the men than in the women [VE:VCO2 50.5 (SD 8.8) vs 57.6 (SD 12.6) P < 0.05]. Ventilatory efficiency during exercise declined significantly with age and was smaller in the men than in the women (men: (VE vs VCO2 slope = 0.13 x age + 19.9; women: VE vs VCO2 slope = 0.12 x age + 24.4). The VO2AT and VO2max were 23 (SD 5) and 39 (SD 7) ml O2 x kg x min(-1) in the men and 18 (SD 4) and 32 (SD 7) in the women, respectively, and declined significantly with age. The VO2AT was reached at 58 (SD 9)% VO2max. Breathing reserve at the end of exercise was 41% and was independent of sex and age. It was concluded from this study that ventilatory efficiency as well as peak oxygen uptake are age and sex dependent in adults.

Adolescent↗
PubMed1985

Working ability and exercise tolerance during treatment of a mild hypertension. I. Comparison between a beta-adreno-receptor blocking drug and a calcium antagonist.

A randomized cross-over trial was undertaken on 21 occupationally active persons who had a stable mild or moderate hypertension with the purpose of comparing the effect of a beta-adreno-receptor blocking agent (atenolol) with that of a calcium channel inhibitor (nifedipine). The doses recommended by the manufactures were used. Atenolol (100 mg) given once a day resulted in a marked hypotensive effect at rest as well as during exercise, the compliance was satisfactory, and the hemodynamic changes were not reflected in unfavourable side effects during muscular exercise or in the subjects own personal assessment of fatigue during the exercise tests which ranged in energy expenditure from about three to six times the resting level. However, unfavourable, modest side effects occurred in two subjects during atenolol medication to the extent that they wanted to terminate the study. Nifedipine therapy with doses of 10 mg, three times a day, resulted in a modest, but statistically insignificant reduction in arterial blood pressure, which contrasts with previous published results. It is suggested that the modest effect is caused or related to the poor compliance and a daily dose that was quantitatively too small. No unfavourable side effects were seen during muscular efforts when the subjects were on nifedipine medication.

Adrenergic beta-Antagonists↗
PubMed1999

Effects of sodium bicarbonate administration on the exercise tolerance of normal subjects breathing through dead space.

STUDY OBJECTIVE: The purpose of this study was to determine whether the administration of sodium bicarbonate to normal individuals would increase their PaCO2 and thereby decrease the ventilatory requirements at a given workload. DESIGN: In this double-blind crossover study, six normal men ingested either 3 mEq/kg NaHCO3 or 1 mEq/kg NaCl once a day for 5 days, in addition to 40 mg of furosemide and 40 mEq KCl. After each 5-day treatment, the subjects underwent a symptom-limited maximal bicycle ergometer exercise test while breathing through external dead space (with a volume of approximately 50% of their FEV1), a second exercise test without any external dead space, and an assessment of their respiratory response to hypercapnia. RESULTS: The administration of the NaHCO3 resulted in a significant increase in the arterial HCO3- from 20.8 to 24.0 mEq/L and a significant increase in the PaCO2 from 31.7 to 36.9 mm Hg at rest that persisted during exercise. During exercise periods with the added dead space, the Borg scores were significantly lower at each workload after the subjects received bicarbonate, but the maximal exercise level did not increase. The mean (+/-SD) slope of the mouth occlusion pressure response to hypercapnia was significantly lower after the administration of NaHCO3 than after NaCl, respectively: 0.73+/-0.41 vs 1.27+/-0.97 cm H2O/mm Hg. CONCLUSION: From this study we conclude that the administration of NaHCO3 results in a significant increase in the PaCO2, decreases the ventilation and the Borg score at equivalent workloads, and decreases the hypercapnic response in normal individuals.

Adult↗
PubMed1995

Effects of fosinopril on exercise tolerance and clinical deterioration in patients with chronic congestive heart failure not taking digitalis. Fosinopril Heart Failure Study Group.

A total of 241 men and women with mild to moderately severe chronic heart failure (New York Heart Association functional class II [90%] or III) and a mean (+/- SD) left ventricular ejection fraction of 25 +/- 7%, entered a 24-week, prospective, double-blind, placebo-controlled trial of 10 or 20 mg/day of fosinopril, a phosphinic acid angiotensin-converting enzyme inhibitor. Patients received concomitant diuretic therapy but not digitalis. Primary end points were mean change in maximal treadmill exercise time and occurrence of prospectively defined clinical events indicative of worsening heart failure (most to least severe): death, withdrawal for worsening heart failure, hospitalization for worsening heart failure, need for supplemental diuretic or emergency room visit for worsening heart failure, and no event. At study end point, treadmill exercise time had improved in the fosinopril versus the placebo group (+28.4 vs -13.5 seconds, p = 0.047). New York Heart Association functional class had improved at end point more frequently (24% vs 13%) and deteriorated less frequently (18% vs 32%) in the fosinopril group (p = 0.003). More patients treated with fosinopril (66% vs 50%) remained free of clinical events indicative of worsening heart failure, and fosinopril-treated patients had less severe clinical events (p = 0.004). Dyspnea, fatigue, and paroxysmal nocturnal dyspnea improved more often and worsened less often in this group (p < or = 0.002), and edema showed a trend toward improvement (p = 0.088). These clinical benefits did not require concomitant digitalis therapy. Fosinopril was associated with an acceptable safety profile.

Aged↗
PubMed1986

Effects of bevantolol and atenolol on symptoms, exercise tolerance and metabolic risk factors in angina pectoris.

To assess the effects of bevantolol on stable angina pectoris of effort and its impact on metabolic risk factors, a comparison study of this beta 1-blocking agent and atenolol was undertaken in 40 subjects (mean age 51 years). After a 4-week, single-blind, placebo washout period, 12 men and 8 women were randomized to receive 150 mg of bevantolol twice daily and 12 men and 8 women to treatment with 100 mg of atenolol once daily in a parallel, double-blind, 12-week treatment phase. Patients were assessed at weeks 2, 6 and 12 after bicycle exercise until angina or ST-segment depression greater than or equal to 0.15 mV appeared. Concentrations of cholesterol lipoproteins and 3 prostaglandin metabolites were determined. One patient receiving bevantolol was withdrawn from the study because of insufficient efficacy and 2 receiving atenolol were withdrawn because of side effects. After 2 weeks of therapy, significant decreases were seen in both groups in the number of angina attacks, mean sitting heart rate, systolic and diastolic blood pressure, mean maximum heart rate during exercise and mean double-product of systolic blood pressure and heart rate at the end of exercise. There was a trend toward significance in the increase of mean duration of exercise and total work performed with both agents, although these values were not statistically significant. Both high density lipoproteins and the ratio of high density lipoproteins to low density lipoproteins increased in the bevantolol group and decreased in the atenolol group. These changes were statistically significant at week 6.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1997

Effect of a heart failure program on hospitalization frequency and exercise tolerance.

BACKGROUND: Most patients with heart failure are currently managed by physicians with little specific expertise in heart failure. This management system has been associated with evidence of suboptimal care, such as high rates of hospital readmission and underuse of ACE inhibitors. The current study was undertaken to determine whether hospitalization rates and functional outcomes are improved when patients are managed by physicians with special expertise in heart failure working in a dedicated heart failure program. METHODS AND RESULTS: All patients with heart failure referred to the Vanderbilt Heart Failure and Heart Transplantation Program between July 1994 and June 1995 were identified. Annual hospitalization rates, medications, and peak exercise capacity before and after referral were compared in patients followed for >30 days. A total of 187 patients were referred during the index time period, of whom 134 (72%) were followed for >30 days. During the year before referral, 94% of the patients were hospitalized (210 cardiovascular hospitalizations) versus 44% of the patients during the year after referral (104 hospitalizations) (53% reduction) (P<.01). Hospitalizations for heart failure decreased from 164 to 60 for all patients regardless of follow-up duration and decreased from 97 to 30 (69% reduction) for patients followed at least 1 year after referral. Eighty-eight of the patients were able to exercise at the time of referral. Peak exercise VO2 in this group increased from 12.8+/-4.7 to 15.7+/-4.8 mL x min(-1) x kg(-1) (P<.01) by 6 months after referral. Loop diuretic doses were on averaged doubled during the first 6 months after referral. CONCLUSIONS: These findings suggest that patients with heart failure have fewer hospitalizations for heart failure and are significantly more functional when managed by heart failure specialists working in a dedicated heart failure program rather than by physicians with limited expertise in heart failure.

Adult↗
PubMed1990

Long-term therapy with benazepril in patients with congestive heart failure: effects on clinical status and exercise tolerance.

Benazepril hydrochloride (CGS 14824A) is an orally active, nonsulfhydryl compound that is transformed in vivo to a long-acting inhibitor of angiotensin-converting enzyme (ACE). Previous studies have shown benazepril to lower blood pressure in hypertensive patients and to confer acute hemodynamic benefits in patients with congestive heart failure (CHF). In the current multicenter investigation, 16 patients with chronic CHF due to left ventricular systolic dysfunction (ejection fraction less than 0.40 at rest) whose symptoms corresponded to New York Heart Association classes II to IV were given open-label benazepril once daily in ascending doses of 2 to 20 mg and followed biweekly for 12 weeks. Evaluation of the 15 subjects who completed the trial showed a progressive increase in treadmill exercise duration (from 7.65 +/- 3.64 [SD] minutes at baseline to 9.74 +/- 3.66 minutes at 12 weeks, P less than .001); augmentation of the mean left ventricular ejection fraction (from 0.266 +/- 0.133 at baseline to 0.292 +/- 0.136 at 12 weeks, P less than .025); relief of exertional dyspnea in 7 of the 15 patients (P less than .02); and improvement in global symptomatic status in 10 of the patients (P less than .01). These responses were accompanied by a reduction in serum ACE activity of 75% (from 27.2 +/- 10.5 IU/L at baseline to 6.7 +/- 1.9 IU/L at 12 weeks, P less than .001), which was independent of dose and duration of treatment. The magnitude of ACE inhibition did not correlate with changes in the efficacy variables. Aside from two instances of symptomatic hypotension (one of which was complicated by volume depletion), the drug was well tolerated.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1984

[Comparative study of the exercise tolerance of patients with autonomic circulatory dystonia, angina pectoris and previous myocardial infarction].

Ninety-eight men were examined. Of these, 13 were practically healthy, 29 had vegetovascular dystonia, 15 stable angina pectoris, and 41 men suffered myocardial infarction. Each group was appraised for work fitness. The double product, work, chrono- and inotropic reserves of the heart, as well as the index of energy losses of the heart per unit of work were calculated. A significant decrease in chrono- and inotropic reserves of the heart were revealed in patients with demonstrable coronary pathology and with cicatricial lesions after myocardial infarction. The patients with vegetovascular dystonia showed inadequate response to the exercise, manifested by greater energy losses of the heart per unit of work as compared to normal.

Adult↗
PubMed1986

Effects of beta-agonists on breathlessness and exercise tolerance in patients with chronic obstructive pulmonary disease.

In a single-blind placebo-controlled trial in 12 patients with advanced chronic obstructive pulmonary disease (COPD) we compared the effects of nebulized salbutamol (1 mg), clenbuterol (30 micrograms) and placebo (4 ml of normal saline) on spirometric indices (FVC, FEV1), maximal expiratory flows (Vmax50 and Vmax25), the distance walked in 6 min (6MD), assessment of breathlessness by visual analogue scale (VAS), and estimates by the patients of perceived exertion (RPE). Both clenbuterol and salbutamol produced significant increases in FEV1, FVC, Vmax50 and Vmax25. With both drugs, 6MD increased significantly (p less than 0.01) and breathlessness decreased significantly without an appreciable increase in RPE after exercise despite the extra distance covered. The absolute improvements in FEV1 and 6MD after clenbuterol were correlated (r = 0.763, p less than 0.01), but these indices were not correlated after salbutamol (r = 0.121, p greater than 0.1). The lack of correlation between the changes in 6MD and FEV1 after salbutamol might indicate that relief of airways obstruction is not the only explanation for the effects on distance walked, at least with salbutamol.

Aged↗
PubMed1985

Improvement in symptoms and exercise tolerance by metoprolol in patients with dilated cardiomyopathy: a double-blind, randomized, placebo-controlled trial.

It has been suspected that the increased sympathetic activity seen in patients with chronic congestive heart failure from dilated cardiomyopathy may be harmful. We therefore tested the long-term effect of metoprolol on eight patients in a double-blind, randomized protocol and 12 patients in an unblinded, crossover protocol who were treated for 12 months (range 10 to 24), and compared them with 16 similar subjects who were treated with placebo for 10 months (range 6 to 12) in a double-blind, randomized protocol. Patients were followed by serial clinical assessment, treadmill testing, radionuclide ventriculography, and echocardiography. Metoprolol-treated patients had an improvement in mean exercise capacity by 3 mets (p less than .0001) while experiencing a significant improvement in functional classification (p less than .001) during both the double-blind and open-label crossover studies and had an improved ejection fraction during the double-blind study (p less than .02). These improvements were not seen in matched control subjects receiving placebo. Seven of 20 patients receiving long-term metoprolol therapy had resolution of nearly all symptoms of heart failure, doubled their exercise capacity, and had progressive improvement in resting radionuclide left ventricular ejection fraction (12.6 +/- 3% to 26.9 +/- 6%) and echocardiographic left ventricular end-diastolic dimension (7.7 +/- 0.5 to 6.5 +/- 0.5 cm). Only one of 21 patients treated was intolerant of metoprolol. We conclude that metoprolol can be given safely to a select group of patients with dilated cardiomyopathy in doses that substantially reduce both resting and exercise heart rates. Long-term beta-blockade improved functional class and exercise capacity in 14 of 20 patients while producing an exceptional clinical response in seven that was accompanied by improved resting parameters of left ventricular function.

Adult↗
PubMed1977

Efficacy of ambulatory systemic vasodilator therapy with oral prazosin in chronic refractory heart failure. Concomitant relief of pulmonary congestion and elevation of pump output demonstrated by improvements in symptomatology, exercise tolerance, hemodynamics and echocardiography.

The long-term efficacy of the new oral vasodilator, prazosin (PZ), was evaluated in nine patients with refractory heart failure due to chronic coronary heart disease. Ventricular function was assessed by cardiac catheterization, echocardiography, and treadmill testing; symptomatic evaluation was carried out for two to four months. One hour following 2-7 mg PZ, control left ventricular filling pressure was reduced (32 to 18 mm Hg, P less than 0.001) and cardiac index was elevated (1.95 to 2.89 L/min/m2, P less than 0.001) for a 6-hour period. After two weeks of PZ 2 to 7 mg four times daily, echographic end-diastolic dimension fell (5.7 to 5.4 cm, P less than 0.001) while shortening fraction increased (27.6 to 30.2%, P less than 0.005). Treadmill exercise duration increased from 209 to 317 seconds (P less than 0.001). Symptoms diminished throughout the duration of follow-up (mean 94 days) with improvement in NYHA functional class (3.7 to 2.2, P less than 0.001). Thus, prazosin possesses sustained nitroprusside-like balanced dilator actions on the systemic arterial and venous systems and is effective in the ambulatory management of chronic severe heart failure.

Administration, Oral↗
PubMed1995

[Spirometric investigation and spiro-ergometric test in evaluation of exercise tolerance in patients suffering from aluminosis and silicosis].

The main purpose of our research was to estimate the ventilation and physical efficiency in 6 patients suffering from aluminosis and silicosis. Chest X-ray examinations, statical spirometric investigations and spiroergometric tests (TSE) were performed. Oxygen levels achieved in this group were equal or even higher than medium values achieved by healthy people. Ability to physical effort can be estimated only using TSE.

Adult↗
PubMed1992

Beneficial effects of pimobendan on exercise tolerance and quality of life in patients with heart failure. Results of a multicenter trial. The Pimobendan Multicenter Research Group.

BACKGROUND: This multicenter trial was conducted to determine the efficacy and safety of pimobendan, an inotropic agent with calcium-sensitizing properties and activity as a phosphodiesterase inhibitor, in patients with heart failure. METHODS AND RESULTS: One hundred ninety-eight ambulatory patients with symptoms of moderate to severe heart failure despite therapy with digitalis and diuretics with or without a single vasodilator were randomly assigned to receive either placebo (n = 49) or pimobendan (n = 149) in a double-blind fashion for 12 weeks. A dose range of pimobendan was used including 2.5 (n = 49), 5 (n = 51), or 10 mg/day (n = 49). One hundred fifty-eight (80%) patients were taking a converting enzyme inhibitor (CEI) and 28 (14%) patients were taking a non-CEI vasodilator. At end point, the 5-mg dose of pimobendan significantly increase exercise duration compared with placebo (121.6 +/- 19.1 seconds, p less than 0.001), whereas the 10-mg dose produced an increase of borderline significance (81.1 +/- 19.5 seconds, p = 0.05). Peak VO2 was significantly increased by 2.23 +/- 0.58 ml/kg/min in the 5-mg group (p less than 0.01 versus placebo). Furthermore, quality of life measured with the Minnesota Living With Heart Failure Questionnaire improved by 8.5 +/- 2.3 units in the 5-mg group compared with 1.3 +/- 2.2 units in the placebo group (p less than 0.01). There were a total of 23 all-cause hospitalizations in the placebo group, which was significantly greater compared with 33 in the three groups treated with pimobendan (p less than 0.01). There were no significant differences between the placebo and pimobendan groups with respect to changes in ejection fraction and plasma norepinephrine measured at baseline and at the completion of the 12-week study, proarrhythmic effect, or the number of patients with a significant adjustment in background therapy. Eleven patients died, including three (6%) on placebo and eight (5%) on pimobendan (p = NS). Among all adverse events, headache tended to be more common in the pimobendan groups compared with placebo, with the incidence increasing with dose (p less than 0.05). CONCLUSIONS: These data demonstrate that pimobendan significantly increases exercise duration, peak VO2, and quality of life in patients with heart failure. Pimobendan appears to be useful adjunctive therapy when added to digitalis, diuretics, and vasodilators.

Analysis of Variance↗
PubMed1995

Addition of zatebradine, a direct sinus node inhibitor, provides no greater exercise tolerance benefit in patients with angina taking extended-release nifedipine: results of a multicenter, randomized, double-blind, placebo-controlled, parallel-group study. The Zatebradine Study Group.

OBJECTIVES: We examined the antianginal and anti-ischemic effects of oral zatebradine, a direct sinus node inhibitor that has no blood pressure-lowering or negative inotropic effects in patients with chronic stable angina pectoris taking extended-release nifedipine. BACKGROUND: Heart rate reduction is considered an important pharmacologic mechanism for providing anginal pain relief and anti-ischemic action in patients with chronic stable angina, suggesting a benefit for sinus node-inhibiting drugs. METHODS: In a single-blind placebo run-in, randomized double-blind, placebo-controlled, multicenter study, patients already receiving extended-release nifedipine (30 to 90 mg once a day) were randomized to receive zatebradine (5 mg twice a day [n = 64]) or placebo (n = 60). All subjects had reproducible treadmill exercise-induced angina at baseline, and after randomization they performed a serial exercise test 3 h after each dose for 4 weeks. RESULTS: Zatebradine reduced rest heart rate both at 4 weeks ([mean +/- SEM] 12.9 +/- 1.23 vs. 2.3 +/- 1.6 [placebo] beats/min, p < 0.0001) and at the end of comparable stages of Bruce exercise (16.7 +/- 1.2 vs. 3.4 +/- 1.2 [placebo] beats/min, p < 0.0001). Despite the significant effects on heart rate at rest and exercise, there were no additional benefits of zatebradine from placebo baseline in measurements of total exercise duration, time to 1-mm ST segment depression or time to onset of angina. Subjects taking zatebradine also had more visual disturbances as adverse reactions. CONCLUSIONS: Zatebradine seems to provide no additional antianginal benefit to patients already receiving nifedipine, and it raises questions regarding the benefit of heart rate reduction alone as an antianginal approach to patients with chronic stable angina.

Adult↗
PubMed1990

Criteria to verify attainment of maximal exercise tolerance test with obese females.

This study compared criteria used to determine attainment of maximal ETT used with normal subjects to results shown by obese subjects. Results indicated that obese subjects do not show the values that normal subjects show for plateau in oxygen consumption, respiratory exchange ratio, predicted maximal heart rate, or perceived exertion. Generally, less than 60% of the obese subjects met criteria for maximal ETT. These findings suggest that alternate criteria and/or alternate testing are needed to ascertain that ETT was maximal. Suggestions include longer treadmill stage times and the use of blood lactate.

Adult↗