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PubMed2004

The influence of exercise tolerance on quality of life among patients with heart failure.

The purpose of this study was to explore the influence of exercise tolerance on quality of life (QOL) among patients with heart failure (HF). A descriptive correlational design was used to guide the study. Forty-nine participants who met the selection criteria were enrolled at a medical center in Taipei. Data were collected by using the Short-Form 36 and treadmill tests including an exercise intensity-increasing test and duration-increasing test. The results revealed the mean scores of QOL in terms of physical functioning and mental functioning were 66.99 and 68.82, respectively. The average peak VO2 (exercise intensity tolerance) was 4.65 mets. The average exercise duration tolerances were 768.55, 1717.04 and 1923.48 s for reaching 50% heart rate reserve (HRR), 90% HRR, and completing the whole test, respectively. Patients whose exercise intensity tolerance was > or = 5 mets or whose exercise duration tolerance was > or = 1800 s had better physical functioning, but a significant difference in mental functioning was not observed between the two groups. The findings of the study support the view that exercise testing is safe, feasible, and effective in evaluating exercise tolerance, and that both exercise duration and exercise intensity tolerance were important factors in determining QOL, particularly in physical functioning, for HF patients.

Aged↗

PubMed1994

Angiotensin-converting enzyme inhibition increases exercise tolerance and muscle blood flow in rats with peripheral arterial insufficiency.

To determine the effect of angiotensin-converting enzyme (ACE) inhibition on exercise tolerance and muscle blood flow (BF) to ischemic limbs, both femoral arteries of male Sprague-Dawley rats (approximately 325 g) were surgically stenosed. Rats were either active (treadmill run, 20 m/min (a) 15% grade, 5 d/wk for 3 wk) or sedentary (limited to cage activity), and assigned to one of three doses of zabicipril at 0.0 (zero), 0.3 (low), and 3.0 (high) mg.kg-1.d-1 administered via food intake (N = 14-15/group). After 3 weeks, the left carotid and caudal arteries were catheterized under anesthesia for BF measurement later in the day. Muscle BF was determined during exercise at two treadmill speeds (20 and 30 m/min) with 85Sr and 141Ce labeled microspheres to ensure a peak BF. Plasma ACE was inhibited 31%, 65% in the low- and high-dose sedentary rats and 75%, 74% in the low- and high-dose active animals, respectively (P < 0.001). Angiotensin-converting enzyme inhibition improved exercise tolerance by 3 weeks, at a low speed (20 m/min) in the sedentary groups (P < 0.025) and in a dose-dependent manner at a higher speed (25 m/min) in the active groups (P < 0.001). Blood pressures and heart rates during running were not different among groups. However, total hindlimb BF, reduced to approximately 33% of normal by femoral stenosis, was increased by ACE inhibition and chronic activity in a dose-dependent manner (P < 0.025). Blood flows to the plantar flexors were most improved (approximately 20-40%; to 124 mL.min-1 x 100 g-1) in the high-dose groups (P < 0.01). The higher run speed did not increase BF above the low speed. Training adaptation, indicated by an enhanced muscle mitochondrial content (P < 0.001), was similar for low- and high-dose active animals. Our results indicate that ACE inhibition improves BF to ischemic muscles and, together with chronic physical activity, improves exercise tolerance. The results from this study support those advocating ACE inhibition in managing appropriate patients with peripheral arterial insufficiency.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1988

Spectrum of exercise intolerance in 45 patients with Ebstein's anomaly and observations on exercise tolerance in 11 patients after surgical repair.

To determine the effects of definitive operation for Ebstein's anomaly on rest and exercise cardiorespiratory function, cycle exercise studies were performed on 38 patients with Ebstein's anomaly before definitive operation and on 11 patients after operation. An atrial septal defect was present in 29 of the 38 preoperative patients and in none of the postoperative patients. Seven of the postoperative patients had tricuspid valvuloplasty and four had valve replacement. Exercise tolerance, as defined by maximal oxygen uptake, was significantly greater in patients after operation for Ebstein's anomaly than in the preoperative patients. However, exercise tolerance for preoperative patients without an atrial septal defect was similar to that for postoperative patients. Tricuspid valve repair or replacement appeared to affect favorably cardiac output response to exercise. Rest systemic arterial oxygen saturation increased from 88 to 95% and exercise saturation from 77 to 93% after operation. Rest ventilatory equivalent for oxygen decreased from 48 +/- 13 preoperatively to 37 +/- 6 postoperatively, and exercise ventilatory equivalent for oxygen decreased from 53 +/- 23 preoperatively to 38 +/- 6 postoperatively. Definitive operation (tricuspid valvuloplasty or replacement and atrial septal defect closure) for Ebstein's anomaly results in significant improvement of exercise tolerance, normalization of systemic arterial oxygen saturation and reduction of excess ventilation at rest and during exercise.

Adolescent↗

PubMed2004

Growth hormone and exercise tolerance in patients with cystic fibrosis.

Cystic fibrosis (CF) is a life-limiting inherited disorder characterised by pulmonary disease, pancreatic dysfunction and symptoms of malnutrition that are all interrelated with low exercise capacity and poor survival rate. Therapy with growth hormone (GH) may improve the reduced dimensional and functional capacity associated with poor nutritional status and catabolism and therefore improve exercise tolerance, quality of life and survival rate in patients with CF. The literature about GH treatment and its effect on exercise tolerance are rather limited, not always consistent and methodological concerns restrict further analysis. GH treatment may have beneficial effects on both growth and exercise tolerance without serious complications in prepubertal children with CF. The observed dimensional changes of the muscular, cardiovascular and pulmonary system seem to improve aerobic exercise capacity and respiratory and peripheral muscle strength. The physiological background of the observed changes is not yet fully understood, therefore, larger-scale studies with an optimised design are required.

Body Composition↗

PubMedDate not supplied

Non-invasive assessment of respiratory muscle function and its relationship to exercise tolerance in patients with chronic obstructive pulmonary disease.

Most patients with chronic obstructive pulmonary disease (COPD) have impaired respiratory muscle function. Maximal oesophageal pressure correlates closely with exercise tolerance and seems to predict the distance walked during the 6-min walk test. This study assessed the non-invasive parameters of respiratory muscle function in 41 patients with COPD to investigate their relationship to pulmonary function tests and exercise tolerance. The COPD patients, who demonstrated the full range of airway obstruction severity, had a mean forced expiratory volume in 1 s of 42.5% predicted (range, 20 - 79% predicted). Both the maximal inspiratory muscle strength and non-invasive tension-time index were significantly correlated with the degree of lung hyperinflation, as expressed by the ratio of residual volume to total lung capacity, and the distance walked in 6 min. We conclude that respiratory muscle function was influenced mainly by lung hyperinflation and that it had an important effect on exercise tolerance in COPD patients.

Aged↗

PubMed1996

Impaired exercise tolerance in hypertensive patients.

PURPOSE: To review information on exercise testing in hypertensive patients and persons at risk for developing hypertension and to determine whether this type of investigation is valuable for diagnosis, prognosis, or assessment of the effect of therapy. DATA SOURCES: A MEDLINE search of English-language articles published between 1985 and 1995 and reviews of the bibliographies of textbooks. STUDY SELECTION: Primary research articles on exercise testing in patients with hypertension, with an emphasis on methods, diagnosis, prognosis, and assessment of drug therapy. DATA EXTRACTION: Study design and quality were assessed, with particular attention paid to methods and aims. Relevant data on hemodynamic responses in hypertensive patients and persons at risk for developing hypertension and correlations to end-organ damage, mortality, and exercise tolerance were analyzed. DATA SYNTHESIS: The exercise capacity of hypertensive patients was found to be reduced by as much as 30% compared with age-matched controls. This exercise impairment increases with age and end-organ damage, and its origin can be traced back to adolescence. Total peripheral resistance also progressively increases. These changes are caused by functional and structural involvement of the cardiovascular system. Diastolic dysfunction of the heart is a prominent factor in this exercise limitation. The blood pressure responses to exercise have prognostic value for the future development of hypertension, end-organ damage, and death. The adequacy of antihypertensive treatment should therefore be evaluated in terms of normalizing these stress-related blood pressure responses. CONCLUSION: Exercise testing is a simple procedure that has great potential for assessing hypertensive patients. More research is necessary, however, to determine whether controlling blood pressure during exercise is beneficial.

Age Factors↗

PubMed1989

Quantitative analysis of the exercise tolerance test for determining the severity of coronary artery disease.

Results were compiled from the literature on the use of the exercise tolerance test to identify patients with severe coronary artery disease. Pooled estimates of sensitivity and specificity were derived for the ability of the exercise tolerance test to identify three-vessel or left main coronary artery disease. There was great variability among the studies examined in the estimated sensitivity and specificity of a given criterion for severe coronary artery disease. This variability could not be explained by reported variations in study design. The findings suggest that the accuracy of the exercise tolerance test and other tests cannot be properly interpreted without much greater detail presented in the literature on patient selection and test administration.

Coronary Disease↗

PubMed1998

Exercise tolerance, body composition and blood lipids in obese African-American women following short-term training.

BACKGROUND: The purpose of this investigation was to examine the exercise tolerance, body composition and blood lipids in African-American women, possessing greater than or equal to 30% body fat, following six weeks of endurance training. METHODS: Oxygen consumption (VO2), central hemodynamics, blood lipids, body weight, body fat, and the body mass index of seven subjects (21.0 +/- 0.8 yrs) were studied. Heart rate (HR), blood pressure (BP), exercise duration, rating of perceived exertion (RPE), blood lactate (bLA) and VO2 were obtained in response to a maximal exercise tolerance test on a motorized treadmill. Subjects trained three times per week for 50 minutes per session (30 minutes at 70% maximal oxygen consumption (VO2max). RESULTS: Dependent "t"-tests revealed significant (p < 0.05) increases in VO2max, 27%; exercise duration, 31%; as well as peak HR, systolic blood pressure (SBP), and bLA. Values for submaximal HR, SBP, RPE during the post-training test were lower. In addition, body weight, body fat and the body mass index decreased 2.2%, 1.3% and 3.4% respectively. There were no changes in blood lipids. CONCLUSIONS: These findings suggest short-term training at 70% VO2max provides the necessary stimulus for obese women to improve exercise tolerance and body composition. However, the training stimulus is insufficient to alter lipid profiles.

Adult↗

PubMed1995

Normalization of hematocrit with recombinant human erythropoietin in chronic hemodialysis patients does not fully improve their exercise tolerance abilities.

In the recombinant human erythropoietin (rHuEPO) treatment of renal anemia, the target level has widely been accepted as approximately 30% of hematocrit (Hct) which means only partial improvement of the anemia. We tried to maintain 1 female and 9 male patients within a normal Hct and to estimate their exercise tolerance abilities. During the study, no serious complications were experienced. Their maximal oxygen uptake (VO2max), evaluated for 1-6 months after reaching the desired Hct of 35-40% with rHuEPO, was 30.7 +/- 2.4 ml of O2/kg/min. These results were significantly higher than those of the control groups whose Hct levels were maintained at around 30%. Although 1 female and 2 male patients were considered to be within the normal exercise tolerance abilities, the others showed lower values in comparison with the Japanese age- and sex-matched values. Thus, it is not always possible to regain full exercise tolerance abilities even after restoring a normal Hct. Unknown factors besides anemia impairing their exercise tolerance abilities might exist in chronic dialysis patients.

Adolescent↗

PubMed1994

Effect of inspiratory pressure support on exercise tolerance and breathlessness in patients with severe stable chronic obstructive pulmonary disease.

BACKGROUND: In patients with chronic obstructive pulmonary disease exercise tolerance is commonly limited by breathlessness. These patients have an increased ventilatory load at rest which is exacerbated during exercise. The purpose of this study was to investigate the effect of supporting ventilation by non-invasive inspiratory pressure support (IPS) during submaximal treadmill exercise in such patients to see if they would experience less breathlessness and improve their exercise capacity. METHODS: Eight men with disabling breathlessness due to chronic obstructive pulmonary disease (COPD) (mean (SD) FEV1 0.73 (0.2) 1) were studied. Patients walked on a treadmill until their sensation of breathlessness, scored at one minute intervals, reached level 5 ("severe") on the 10-point Borg scale. Studies were performed with IPS (mean airway pressure 12-15 cm H2O), continuous positive airway pressure (CPAP 6 cm H2O), and with oxygen (2 l/min via a mask) in random order on three separate days. Each of these walks was compared with a control walk using a sham circuit (breathing air via an oxygen mask at 2 l/min from an unlabelled cylinder), and with a baseline walk in which patients walked freely on the treadmill. On cessation of exercise, distance achieved and a leg fatigue score were recorded. RESULTS: No patients stopped due to leg fatigue, all stopping only when their sensation of breathlessness had reached level 5 on the Borg scale. IPS improved median walking distance by 62% compared with the control walk (sham circuit). There was no change in walking distance with either CPAP or oxygen at 2 l/min. There was no difference between the control and the baseline walks. CONCLUSIONS: Inspiratory pressure support can reduce breathlessness and increase exercise tolerance to submaximal treadmill exercise in patients with COPD. This could have implications for the rehabilitation of these severely disabled patients.

Aged↗

PubMed2004

Motor performance, exercise tolerance, and health-related quality of life in children on dialysis.

In contrast to the adult population, little is known regarding health-related quality of life and exercise tolerance in children with end-stage renal disease (ESRD) undergoing chronic intermittent hemodialysis. We designed a pilot study to investigate whether research into this area is indicated. The aim of this study was to describe the motor skills, exercise tolerance, and health-related quality of life in children with ESRD. The study population consisted of ten hemodialysis patients (aged 7-16 years). In eight children motor proficiency according to Bruininks-Oseretsky was determined. In all ten children a progressive exercise test on a treadmill was performed. The results were compared with an age-matched healthy reference group. Nine children filled in the TNO-AZL Child Quality of Life (TACQOL) scoring list. One child had a markedly reduced fine motor skills capacity; another five children scored < or = -2 SD compared with healthy children in gross motor skills. Seven children showed a diminished VO(2)max (per kilogram body weight); six of these are physically inactive. Four of these seven children did not sustain the maximum workload. The self-assessed physical and mental health of children on dialysis seems comparable to the general population. We found no correlation between exercise performance or motor skills and hemoglobin levels, Kt/V, and time on dialysis. In conclusion, in this study most children had a reduced exercise tolerance and gross motor skills. There was no difference in fine motor skills. Pediatric dialysis patients report a good health-related quality of life.

Adolescent↗

PubMed1993

Following PTCA exercise tolerance is only moderately correlated with cinevideo-densitometric measurement of restenosis.

There is a pressing need for a non-invasive marker of restenosis following percutaneous transluminal coronary angioplasty. Computerised measurement of restenosis has not been used in conjunction with exercise test variables reflecting maximum exercise capacity. Thus we investigated thirty consecutive patients undergoing repeat coronary angiography for restenosis who had a satisfactory symptom limited exercise test. Exercise test variables namely ST segment depression, maximum exercise tolerance and rate/pressure product were correlated with the percentage stenosis measured by videodensitometry. Maximum exercise tolerance expressed in metabolic equivalents was correlated with restenosis severity (correlation coefficient -0.52, p = 0.003) as was maximum duration of exercise (correlation coefficient -0.46, p = 0.01). Maximum ST segment depression on exertion was not correlated with the degree of restenosis. In assessing patients after angioplasty exercise tolerance is related to the severity of restenosis. However the degree of variation within this relationship is such that it cannot be used confidently in the clinical setting to predict restenosis.

Angioplasty, Balloon, Coronary↗

PubMed2001

Skeletal muscle oxidative capacity and exercise tolerance in rats with heart failure.

PURPOSE: Past research has shown the development of exercise intolerance after myocardial infarction (MI). The purpose of this study was to test the hypothesis that reductions in oxidative enzyme activity, in a variety of skeletal muscles, coincide with the development of exercise intolerance in a rat model of chronic heart failure (CHF) induced by MI. METHODS: The animals were initially divided into two groups: sham-operated controls (Sham) and animals in which a MI was surgically induced. MI rats were then subdivided into two groups according to left ventricular end-diastolic pressure (LVEDP): <20 mm Hg [small MI (SMI)] and > 20 mm Hg [large MI (LMI)]. Exercise tolerance was measured by performing a progressive run to fatigue test (RTF). Citrate synthase (CS), 3-hydroxyacyl CoA dehydrogenase (HADH), and malate dehydrogenase (MDH) activities were measured in six hindlimb muscles. RESULTS: After approximately 6 wk of recovery, LVEDP differed among groups (P < 0.05): Sham (1 +/- 1 mm Hg, N = 7), SMI (7 +/- 2 mm Hg, N = 7), and LMI (30 +/- 2 mm Hg, N = 6). RTF was 20 +/- 1 min for Sham, 25 +/- 3 min for SMI, and 11 +/- 2 min for LMI (P < 0.05 for LMI vs Sham, SMI). Significant reductions in enzyme activity were found for all three enzymes in the red portion of the gastrocnemius muscles of LMI. However, no significant correlation was found between RTF and CS, HADH, or MDH in any muscle of the three groups of animals. DISCUSSION: The results of the present study demonstrate that severe left ventricular dysfunction is associated with reductions in exercise tolerance and modest decreases in oxidative enzyme activities in selected muscles. It does not appear, however, that the development of exercise intolerance in CHF and oxidative enzyme activities are mechanistically related to one another.

3-Hydroxyacyl CoA Dehydrogenases↗

PubMed1993

Physician characteristics affecting referral decisions following an exercise tolerance test.

OBJECTIVE: To examine whether physician background and attitudes were altered to the decision to refer a patient with chronic angina to a cardiologist following the results of an exercise tolerance test. DESIGN: Mailed questionnaire asking family physicians and internists how they would make referral decisions for a patient with classic angina in a detailed case vignette. PARTICIPANTS: Two hundred sixty-five family physicians and 105 internists. OUTCOME MEASURES: Physician referral decisions following results of an exercise tolerance test. RESULTS: Only 15% of the respondents believed that the patient should have been directly referred for cardiac catheterization without conducting an exercise tolerance test previously. Data on the remaining 85% of physicians were analyzed to identify factors influencing referral decisions. These physicians were significantly more likely to refer a patient if they were concerned about a lawsuit (68% vs 53% following a test result suggesting coronary disease and 40% vs 24% following a normal test result). Referral decisions were significantly more likely to be changed on the basis of the test result if the test was administered to determine the need for cardiac catheterization (50% vs 34%) or if the physician was a family practitioner rather than an internist (47% vs 24%). A physician's number of years in practice, experience with patients with angina, and board certification were not associated with referral decisions. CONCLUSIONS: Many physicians with very different attitudes and backgrounds order diagnostic tests for reasons other than to make referral decisions. This problem appeared to be less prevalent among family physicians than internists, and it may partly be due to fear of lawsuits or lack of knowledge about how the test should be used.

Angina Pectoris↗

PubMed1992

Acute effect of consumption/omission of breakfast on exercise tolerance in adolescents.

The purpose of this study was to determine the acute effects of the consumption or omission of breakfast on exercise tolerance in adolescents. Physically active adolescents (14 males and 21 females) were randomly assigned to receive a breakfast (B) or placebo (P) after an overnight fast. Exercise tolerance tests were done 1.5 hours (test 1) and again 4 hours (test 2) after consuming B or P and consisted of cycling on a stationary bike for 4 minutes at each of four consecutive power settings: 25, 50, 75, and 100 watts. Blood glucose and beta-hydroxybutyrate concentrations were measured before both tests. VO2 and VCO2 were measured during minute 3 of cycling at loads 50 and 75 watts and were used to compute the respiratory exchange ratio (RER). Heart rates (HR) were monitored throughout the test and ratings of perceived exertion (RPE) were made at the end of each 4 min interval. Repeated measures ANOVA revealed that there were no differences in RPE; however, differences for HR and RER did exist. Mean RER values were higher for the males receiving B vs males receiving P during test 1. For females, HR were higher for P compared B, and beta-hydroxybutyrate was significantly elevated for P before test 2. The data suggest that exercise tolerance as indicated by the ratings of perceived exertion are unaffected by prior ingestion of a breakfast but breakfast does affect the physiologic responses to exercise.

Adolescent↗

PubMed1988

Relationships between heart rate, exercise tolerance and cardiac output in atrial fibrillation: the effects of treatment with digoxin, verapamil and diltiazem.

Six patients with chronic atrial fibrillation (AF) took single doses of digoxin, verapamil and diltiazem, alone and in combination. Three hours after dosing, resting and post-exercise heart rate, exercise tolerance and resting and post-exercise cardiac output were measured. Post-exercise heart rates ranged from 167 bpm (after placebo) to 122 bpm (after digoxin plus diltiazem) (P less than 0.05). However, the lower ventricular rates seen after treatment with the calcium antagonists were not associated with improved exercise tolerance, which did not differ significantly between the various treatments. Reduction of the ventricular rate was associated with a small increase in stroke volume but the benefits of this were offset by a rate related reduction in cardiac output. Further reduction of the rapid ventricular rates seen in digitalized patients with AF does not appear to be of benefit in terms of improving either exercise tolerance or cardiac output.

Aged↗

PubMed2001

[Calf flow reserve measured by venous-occlusion near-infrared spectroscopy: relationship to exercise tolerance].

OBJECTIVES: The correlations between calf flow reserve evaluated with venous-occlusion near-infrared spectroscopy, air plethysmography or skin laser Doppler flowmetry were investigated in patients with cardiovascular diseases. The relationships to exercise tolerance during upright bicycle exercise were also examined. METHODS: The calf flow reserve (blood flow after 5 min of arterial occlusion/basal blood flow) evaluated by the above three methods and peak oxygen uptake (peak VO2) on bicycle exercise were measured in 24 male patients (mean age 65.0 +/- 7.7 years, left ventricular ejection fraction 24-86%). RESULTS: There was a good correlation between flow reserve by near-infrared spectroscopy (8.0 +/- 3.8) and air plethysmography (7.9 +/- 3.1; r = 0.90). However, there was a weak correlation between flow reserve by near-infrared spectroscopy and skin laser Doppler flowmetry (3.4 +/- 1.7; r = 0.42). There was a good correlation between flow reserve by near-infrared spectroscopy and peak VO2 (r = 0.69), or flow reserve by air plethysmography and peak VO2 (r = 0.53). However, there was no significant correlation between flow reserve by skin laser Doppler flowmetry and peak VO2 (r = 0.18). CONCLUSIONS: Calf flow reserve evaluated by venous-occlusion near-infrared spectroscopy relates to the flow reserve in the muscle tissue and is minimally affected by the flow reserve in the skin. The flow reserve in the muscle tissue is related to exercise tolerance, but the flow reserve in the skin is not, in patients with cardiovascular diseases.

Aged↗

PubMed1981

Acute and long-term effects of vasodilator therapy on resting and exercise hemodynamics and exercise tolerance.

The acute hemodynamic response to vasodilators in patients with chronic heart failure has been well characterized, but less is known about the long-term hemodynamic effects of vasodilator therapy. We measured hemodynamic variables at rest and during upright exercise in 11 patients during the initiation of therapy with oral hydralazine and sublingual isosorbide dinitrate and, in eight of these, after 3 months of continuous treatment. Marked initial increases in resting cardiac output and stroke volume and reductions in wedge pressure were sustained during chronic therapy. Similarly, the early improvement in exercise hemodynamic measurements persisted in most subjects. Exercise tolerance, quantified as the maximum duration of treadmill exercise, increased modestly (7.7 +/- 2.6 to 8.9 +/- 3.3 minutes, 0.05 less than p less than 0.10) after several days on vasodilators and further (10.2 +/- 3.7 minutes, p less than 0.01) during long-term treatment. The acute hemodynamic effects of vasodilator therapy at rest or during exercise did not correlate well with the changes in exercise tolerance. Our findings suggest that the combination of hydralazine and isosorbide dinitrate improves cardiac performance at rest and during exercise in patients with chronic heart failure and that this improvement persists during chronic therapy. In most patients, this hemodynamic improvement is accompanied by greater exercise tolerance.

Acute Disease↗