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PubMed1998

[The calcium antagonists diltiazem and nifedipine: a comparison of their efficacy in single and long-term use in patients with stable stenocardia of effort].

AIM: To compare efficacy of diltiazem and nifedipine in single dose and long-term treatment. MATERIALS AND METHODS: A randomised double-blind cross-over study enrolled 17 patients suffering from coronary heart disease (CHD) with stable angina of effort (SAE). For 1 month, each patient received diltiazem and nifedipine (60-90 mg 4 times a day and 20-30 mg 4 times a day, respectively). The effect was assessed by the pharmacodynamic test after the initial dose and in the end of each treatment course. RESULTS: In 14 eligible patients both drugs reduced the number of SAE attacks and nitroglycerin tablets, diltiazem efficiency being somewhat higher. Single doses of diltiazem and nifedipine produced the same action. In long-term treatment nifedipine effect became shorter, diltiazem effect did not change. Before the morning dose of nifedipine (11.5 hours after the previous dose) exercise tolerance of this drug worsened. This may be due to withdrawal syndrome. As to diltiazem, its exercise tolerance improved. CONCLUSION: In long-term treatment of CHD with SAE diltiasem is more effective and safe than nifedipine.

Aged↗

PubMed1982

Prognostic value of exercise testing, coronary angiography and left ventriculography 6--8 weeks after myocardial infarction.

This study provides data on a consecutive series of 179 survivors of acute myocardial infarction (MI) who had symptom-limited treadmill exercise testing, coronary angiography and left ventriculography within 6--8 weeks after infarction. No patient died. The prevalence of multivessel disease was higher in the symptomatic survivors (79%) (p less than 0.001). The prevalence of multivessel disease in inferior MI was 63% and in anterior MI 42% (p less than 0.001). Left ventricular impairment was more severe in anterior and preexisting MI than in inferior and nontransmural MI (p less than 0.005). During a mean follow-up of 28 months, 11 cardiac deaths and 12 reinfarctions occurred. The total mortality rate was 22% (10 of 46) in patients with an ejection fraction less than 30% or three-vessel disease and 1% (one of 133) in patients with an ejection fraction greater than or equal to 30% and one- or two-vessel disease (p less than 0.001). A group at high risk of mortality is thus identified by angiography. The total reinfarction rate was 9% (11 of 121) in patients with an exercise tolerance of less than 10 minutes (Bruce protocol) and 2% (one of 58) in patients with an exercise tolerance of 10 minutes or more (p less than 0.1). The 58 patients who had an exercise tolerance of 10 minutes or more had a very low risk for cardiac death or reinfarction.

Aged↗

PubMed1992

Exercise limitation and pulmonary rehabilitation in chronic obstructive pulmonary disease.

Impairment of exercise tolerance is a common problem in patients with severe chronic obstructive pulmonary disease. The cause of exercise intolerance in patients with severe chronic obstructive pulmonary disease is multifactorial and includes impaired lung mechanics, fatigue of inspiratory muscles, impaired gas exchange, right ventricular dysfunction, malnutrition, occult cardiac disease, deconditioning, and psychologic problems; however, impaired lung mechanics and gas exchange abnormalities seem to be the major limiting factors. Recently, the approach to management of pulmonary rehabilitation in patients with chronic obstructive pulmonary disease has changed because improvement in exercise tolerance has been demonstrated after pulmonary rehabilitation. Other adjunctive measures that have been shown to contribute to the observed improvement in exercise tolerance include administration of oxygen, nutritional support, cessation of smoking, and psychosocial support. The roles of ventilatory muscle endurance training, respiratory muscle rest therapy, nasally administered continuous positive airway pressure, and training of the muscles of the upper extremities are less clearly defined.

Dyspnea↗

PubMed1993

[Skeletal and respiratory muscle strength in chronic heart failure].

BACKGROUND: The aim of this study was to investigate limb and respiratory muscle strength in chronic heart failure (CHF). METHODS: Our study population consisted of 45 male CHF patients, 25 in NYHA Class II and 20 in NYHA Class III, and 22 male post-MI patients without left ventricular dysfunction (LVEF > 50%). All patients underwent assessment of respiratory muscle strength by maximal inspiratory (MIP) and expiratory (MEP) pressures, of handgrip force and peak torque developed during isokinetic Knee extension (EX) (quadriceps) and flexion (hamstring) at 120 degrees/sec. RESULTS: CHF patients showed a significant decrease in all limb and respiratory muscle strength compared to control patients. Moreover, NYHA Class III patients showed significantly reduced values of MIP, handgrip, and EX forces, as well as significantly reduced exercise tolerance in terms of METS (2.8 +/- 0.9 vs 4.4 +/- 1.2, p < .05) and anaerobic threshold level (9.4 +/- 3 vs 12.8 +/- 1.7 mlO2/Kg, p < .05), as compared to those patients in NYHA Class II, while no significant differences were observed in LVEF, cardiac index and pulmonary capillary wedge pressures. Weak, but significant (p < .05) were the correlations between limb muscle and respiratory muscle strength. No correlations were found between muscle force and hemodynamic parameters. Significant correlations (from p < .05 to p < .0001) were found among exercise tolerance and limb muscle strength, but not between exercise tolerance and respiratory muscle strength. In summary: 1) respiratory and skeletal muscle strength is impaired in CHF; 2) respiratory and limb muscle strength reductions are partially related to each other; 3) the degree of central hemodynamic impairment is not correlated with muscle force. Deconditioning could be a major determinant of skeletal but not respiratory muscle weakness. Other factors link limb and respiratory weakness in CHF.

Adult↗

PubMed1997

Effect of acute bicarbonate administration on exercise responses of COPD patients.

Patients with severe chronic obstructive pulmonary disease (COPD) are limited in their exercise tolerance by the level of ventilation (VE) they can sustain. We determined whether acutely increasing blood bicarbonate levels decreased acid stimulation to the respiratory chemoreceptors during exercise, thereby improving exercise tolerance. Responses were compared with those obtained during 100% O2 breathing (known to reduce VE in these patients) and to the responses of healthy young subjects. Participants were six patients with severe COPD (forced expired volume in 1 s = 31 +/- 11% predicted) but without chronic CO2 retention and 5 healthy young subjects. Each subject performed three incremental cycle ergometer exercise tests: 1) control, 2) after ingestion of 0.3 g.kg-1 of sodium bicarbonate and 3) while breathing 100% O2. During these tests VE was measured continuously and arterialized venous blood (patients) or arterial blood (healthy subjects) was sampled serially to assess acid base variables. Bicarbonate loading increased standard bicarbonate by 4-6 mmol.L-1 and this elevation persisted during exercise. In both groups, bicarbonate loading resulted in a substantially higher arterial pH; arterial PCO2 was either unchanged (healthy subjects) or mildly (averaging 5 torr) higher (COPD patients). However, in neither group did bicarbonate loading result in an altered VE response to exercise or an increase in exercise tolerance. In contrast, superimposing hyperoxia on bicarbonate ingestion yielded, on average, 24% reduction in VE and 50% increase in peak work rate in the patients (but not in the healthy young subjects). We conclude that acute bicarbonate loading is not an ergogenic aid in patients with severe COPD.

Adult↗

PubMed1995

Normal behaviour of circulatory parameters during exercise. Reference values for heart rate and systemic blood pressure. The ECCIS Project data. Epidemiologia e Clinica della Cardiopatia Ischemica Silente.

The study of simultaneous variations in heart rate (HR) and systemic blood pressure is of great interest in ergometric practice complementing the analysis of the ST segment by ECG. This paper examines data proceeding from 500 consecutive, normal, exercise stress tests with the aim of offering reference values on the step-by-step behaviour of HR, systolic and diastolic blood pressure (SBP, DBP) during exercise in a normal population. The sample comes from a large epidemiological study (ECCIS Project) conducted on 4842 healthy, working men, aged 40-59, which proposes to identify, by a 3 stage procedure, subjects with totally asymptomatic coronary artery disease (type I silent ischemia). A further aim of our paper is to examine the influence of some physiological variables (age, height, weight, body mass index, resting HR, SBP and DBP) on the response to effort of HR, SBP and DBP; reciprocal HR/SBP adjustment during exercise; maximal attained workload and recovery time. Due to a preliminary observation that the rate of step-by-step increase in HR and SBP is inversely related to total duration, the population was split into 4 groups according to exercise tolerance (defined by maximal attained workload) to elaborate reference values. Furthermore our data demonstrate that: 1) SBP increases more rapidly with respect to HR for older and heavier subjects; 2) Exercise tolerance is inversely related to age, baseline HR and SBP, and directly related to weight and height; 3) return to baseline conditions, during recovery, is quicker for subjects with better exercise tolerance and lower baseline HR, SBP and weight.

Adult↗

PubMed2005

The effectiveness of different combinations of pulmonary rehabilitation program components: a randomized controlled trial.

STUDY OBJECTIVES: To study the short-term and long-term effects of combining activity training or lectures to exercise training on quality of life, functional status, and exercise tolerance. DESIGN: Randomized clinical trial. SETTING: Outpatient pulmonary rehabilitation center. PARTICIPANTS: Forty-three outpatients with COPD. INTERVENTIONS: Patients were randomized to one of three treatment groups: exercise training alone, exercise training plus activity training, and exercise training plus a lecture series. The mean treatment period was 10 weeks. MEASUREMENT: The Chronic Respiratory Disease Questionnaire, the modified version of the Pulmonary Functional Status and Dyspnea Questionnaire, and the COPD Self-Efficacy Scale were administered at baseline, and 6, 12, 18, and 24 weeks from the beginning of the rehabilitation program. The 6-min walk test was used to measure exercise tolerance. RESULTS: Benefits of activity training combined with exercise included less dyspnea (p < or = 0.04) and fatigue (p < or = 0.01), and increased activity involvement (p < or = 0.02) and total functional status (p < or = 0.02) in the short term compared to comparison treatment groups for comparatively older participants. Compared to the lecture series adjunct, the activity training adjunct resulted in significantly higher gains in total quality of life (p = 0.04) maintained at 24 weeks. Significantly worse emotional function and functional status resulted from the lecture series adjunct in the oldest participants (p < or = 0.03). Treatment groups did not differ significantly on exercise tolerance or self-efficacy. CONCLUSIONS: Evidence for additional benefits of activity-specific training combined with exercise was found. A behavioral method emphasizing structured controlled breathing and supervised physical activity was statistically significantly more effective than didactic instruction in facilitating additional gains and meeting participants' learning needs.

Age Factors↗

PubMedDate not supplied

Laryngoplasty with ventriculectomy or ventriculocordectomy in 104 draft horses (1992-2000).

OBJECTIVE: To evaluate efficacy and safety of laryngoplasty with vetriculectomy (VE) or ventriculocordectomy (VCE) for treatment of laryngeal hemiplegia (LH) in draft horses. STUDY DESIGN: Retrospective study. SAMPLE POPULATION: One hundred four draft horses used for competitive hitch competitions. METHODS: Medical records and postoperative endoscopy for competitive hitch draft horses diagnosed with left LH and treated with laryngoplasty and VE or VCE between January 1992 and December 2000 were reviewed. Follow-up information was obtained from telephone interviews with owners and trainers, and performance scores of 1 to 3 were assigned in which 1 was defined as a horse that was unable to perform (abnormal respiratory noise with or without exercise intolerance), 2 was able to perform but not for its intended use (exercise tolerant but abnormal respiratory noise), and 3 was performing as expected for its intended use (exercise tolerant, no abnormal respiratory noise). RESULTS: One hundred four horses that had 111 laryngoplasty procedures were included. All horses had preoperative performance scores of 1. Follow-up information was available for 79 horses. Improvement in postoperative performance (exercise tolerant, with or without abnormal respiratory noise) was reported in 92% of horses. Respiratory noise was eliminated in 72% (57 horses) of horses. Postoperative performance scores were the following: 3 in 57 (72%) horses, 2 in 16 (20%) horses, and 1 in 6 (8%) horses. There was no significant difference in postoperative performance based on preoperative grade of LH. There was a trend for horses with >/=70% of possible maximal abduction postoperatively to have a performance score of 3. Postanesthetic complications included prolonged recovery (4 horses, 4%) and myopathy or neuropathy (7 horses, 7%). One of these horses was killed because it did stand; triceps myopathy and encephalopathy were confirmed on necropsy. CONCLUSIONS: Laryngoplasty with VE or VCE is an effective and safe procedure for the treatment of LH in the draft horse. Repeat laryngoplasty can be performed successfully, with good performance outcome after laryngoplasty failure. Complications associated with general anesthesia and laryngoplasty in draft horses are higher than reported for light breed horses under similar conditions. CLINICAL RELEVANCE: For LH, laryngoplasty with VCE or VE under general anesthesia is recommended to eliminate abnormal respiratory noise and improve performance in most competitive hitch draft horses.

Anesthesia, General↗

PubMed1996

Exercise training in patients with heart failure. A randomized, controlled trial.

OBJECTIVE: To assess the benefit of exercise training in patients with heart failure caused by left ventricular systolic dysfunction and to further describe the physiologic changes associated with exercise training in these patients. DESIGN: Randomized, controlled trial. SETTING: Urban outpatient clinic. PATIENTS: 40 men with compensated heart failure who were receiving standard medical therapy were randomly assigned to an exercise-training group or to a control group that did not exercise. Fifteen of the 21 patients assigned to exercise training and 14 of the 19 patients assigned to the control group completed the study. INTERVENTION: Patients assigned to exercise training participated in a program of three exercise sessions per week for 24 weeks. MEASUREMENTS: Symptom-limited exercise tests with gas exchange analysis done just before randomization, at week 12, and at week 24. RESULTS: At week 24, the following changes (mean +/- SE) were seen in patients in the exercise group and patients in the control group, respectively; exercise duration, 2.8 +/- 0.6 minutes and 0.5 +/- 0.5 minutes; peak oxygen consumption (VO2), 231 +/- 54 L/min and 58 +/- 38 L/min; peak ventilation, 12 +/- 3 L/min and -4 +/- 3 L/min; peak heart rate, 10 +/- 4 beats/min and -2 +/- 4 beats/min; and peak power output, 20 +/- 6 W and 2 +/- 5 W. Differences between the increases occurring in the exercise group and the changes occurring in the control group were significant (P < 0.05). Among patients in the exercise group, 85% of the increase in peak VO2 occurred by week 12, and 46% of the increase in peak VO2 was caused by the increase in peak heart rate. CONCLUSION: Exercise training does not appear to be contraindicated in patients with compensated heart failure. Exercise training improved exercise tolerance, as measured by increases in peak VO2, exercise duration, and power output. This improved exercise tolerance was caused in part by an increase in peak heart rate.

Adult↗

PubMedDate not supplied

[Chronic myocardial infarct with left ventricular dysfunction: the clinical aspects and exertion tolerance].

UNLABELLED: The objective of the study is the assessment of the exercise functional capacity of the patients with chronic myocardial infarction and left ventricular disfunction and the relevance of some clinical peculiarities of them in contrast with patients without left ventricular performance. METHODS: There have been studied 105 patients with chronic myocardial infarction, in a period of time between 1992-1995. There has been taken, as an objective criterium of the assessment of LV disfunction, the ejection fraction (EF) measured by echo 2D at 52 patients. There were created the groups with EF 50%(32p), EF = 35-50% (12p) and EF = 35% (8p). The clinical parameters were: the number of coronary risk factors (CRF), the NYHA class, the exercise test and the assessment of VO2max. The statistical comparison has been made by using an IBM computer 486, programme FoxPro and EPI/INFO. RESULTS AND DISCUSSIONS: 50% of the patients with EF > 50% (16/32) had a good exercise tolerance (MET > 5); 13 patients (65%) from the patients with EF < 50% had MET < 5. Similarly, there is no correlation between the low EF (50%) and VO2max. The analysis of the exercise tolerance correlated with the functional class NYHA shows its diminution at patients with cardiac failure (classes I and II) compared with those without dyspnea (67% vs 42%, p < 0.01 and respectively 80% vs 42%, p < 0.05). There are similar differences in the assessment of VO2max at patient from classes III (p < 0.01) and II (p < 0.03) compared with class 0. Dyspnea, as a clinical parameter, does not correlate with low EF, but has significant association with VO2max. The study of the degree of charge in CRF at patients with EF < 50% reveals the following: older age (p < 0.02), the presence of arterial hypertension (p < 0.01) and the greater prevalence of DM (p < 0.05). CONCLUSION: 1. There is no correlation between the degree of the left ventricular disfunction and the exercise capacity. 2. VO2max is significantly lower at patients with dyspnea, especially from classes II and III. 3. Patients with myocardial infarction and LV disfunction have statistically more CRF, like older age, HTA, DM.

Chi-Square Distribution↗

PubMed2004

Relationship between arterial blood gas values, pulmonary function tests and treadmill exercise testing parameters in patients with COPD.

OBJECTIVE: There have been controversial reports regarding the relationship between exercise tolerance and resting pulmonary function in patients with COPD. The aim of this study was to examine the relationship between resting pulmonary function tests (rPFT) and cardiopulmonary exercise testing parameters (CETP) and their value in estimating exercise tolerance of patients. METHODOLOGY: In total, 45 patients with COPD (nine females, 36 males; mean age 61.2 +/- 11.2) and 21 healthy subjects (four females, 17 males; mean age 60.3 +/- 9.7) as a control group were studied. COPD patients (group I) were divided into three subgroups according to their FEV(1) (mild/group II: FEV(1) 60-79% of predicted; moderate/group III: FEV(1) 40-59%; severe/group IV: FEV(1) < 40%). In controls FEV(1) was >/= 80%. RESULTS: There were significant correlations between FEV(1) and CETP in group III (maximal O(2) consumption (mVO(2)), r= 0.35, P < 0.005; total treadmill time (TTT), r= 0.31, P < 0.01; total metabolic equivalent values (TMET), r= 0.29, P < 0.01)) and in group IV (mVO(2), r= 0.49, P < 0.001; TTT, r= 0.45, P < 0.005; TMET, r= 0.31, P < 0.01; peak heart rate (pHR), r= 0.29, P < 0.02; frequency of ventricular extrasystole (fVES), r=-0.27, P < 0.05). Additionally, in group IV there were significant correlations between PaO(2) and CETP (mVO(2), r= 0.41, P < 0.02; TTT, r= 0.38, P < 0.03; TMET, r= 0.31, P < 0.05; pHR, r= 0.29, P < 0.05; fVES, r=-0.28, P < 0.05). CONCLUSION: There are significant correlations of resting FEV(1)% predicted and PaO(2) values with CETP in patients with moderate and severe COPD and these parameters may also have a role as indicators of exercise tolerance in these COPD patients.

Aged↗

PubMed1994

The importance of exercise training in rehabilitation of patients with end-stage renal disease.

Exercise capacity in patients with kidney failure undergoing dialysis is low compared with age-predicted values. The level of exercise tolerance in these patients is such that the energy requirements for activities of daily living and occupational tasks impinge on their capacity to perform these tasks. Therefore, it is not surprising that many patients do not seek or are unable to work because they are physically unable to sustain the energy required for such activity. There are several ways to increase exercise tolerance in these patients--transplant, exercise training, and recombinant human erythropoietin (epoetin) therapy. Successful kidney transplant increases exercise capacity to near normal values for sedentary healthy individuals. Exercise training after transplant further increases exercise capacity and counteracts some of the negative side effects of glucocorticoid therapy, such as muscle wasting and excessive weight gain. Exercise training in patients on dialysis increases exercise tolerance approximately 25% (in studies performed before epoetin administration). Similar increases are observed after correction of the anemia of kidney failure with epoetin. However, the increase in exercise capacity is small compared with the magnitude of change in hematocrit level. It is possible that epoetin therapy unmasks a muscle limitation to exercise that may be improved by exercise training. Anecdotal evidence suggests that exercise training in patients on epoetin therapy may result in an exercise capacity similar to that of transplant recipients. However, epoetin therapy to improve hematocrit levels does not automatically make patients exercise. Active counseling and encouragement are necessary to improve physical functioning.(ABSTRACT TRUNCATED AT 250 WORDS)

Exercise↗

PubMed2003

Effects of prior exercise on metabolic and gas exchange responses to exercise.

'Warm-up' activity is almost universally performed by athletes prior to their participation in training or competition. However, relatively little is known about the optimal intensity and duration for such exercise, or about the potential mechanisms primed by warm-up that might enhance performance. Recent studies demonstrate that vigorous warm-up exercise that normally results in an elevated blood and presumably muscle lactate concentration has the potential to increase the aerobic energy turnover in subsequent high-intensity exercise. The reduced oxygen deficit is associated with a reduction in both the depletion of the intramuscular phosphocreatine stores and the rate at which lactic acid is produced. Furthermore, the oxygen uptake 'slow component' that develops during high-intensity, ostensibly submaximal, exercise is attenuated. These factors would be hypothesised to predispose to increased exercise tolerance. Interestingly, the elevation of muscle temperature by prior exercise does not appear to be implicated in the altered metabolic and gas exchange responses observed during subsequent exercise. The physiological mechanism(s) that limit the rate and the extent to which muscle oxygen uptake increases following the onset of exercise, and which are apparently altered by the performance of prior heavy exercise, are debated. However, these mechanisms could include oxygen availability, enzyme activity and/or availability of metabolic substrate, and motor unit recruitment patterns. Irrespective of the nature of the control mechanisms that are influenced, 'priming' exercise has the potential to significantly enhance exercise tolerance and athletic performance. The optimal combination of the intensity, duration and mode of 'warm-up' exercise, and the recovery period allowed before the criterion exercise challenge, remain to be determined.

Acidosis, Lactic↗

PubMed2005

Treating heart failure with enhanced external counterpulsation (EECP): design of the Prospective Evaluation of EECP in Heart Failure (PEECH) trial.

BACKGROUND: Enhanced external counterpulsation (EECP) treatment can improve exercise tolerance in patients with ischemic heart disease; however, the possible benefits of EECP in patients with stable heart failure (HF) and left ventricular dysfunction (LVD) are unclear. An open pilot study showed significant increases in exercise tolerance in HF patients undergoing EECP. Thus a larger, controlled study of EECP in patients with stable HF (New York Heart Association [NYHA] classes II and III) and LVD was undertaken. METHODS AND RESULTS: The PEECH trial is a controlled, randomized, single-blind, parallel-group, multicenter study of 187 patients with symptomatic but stable HF (NYHA classes II and III) and an LV ejection fraction < or =35% was designed to assess the efficiency of EECP in patients with stable HF. Medical therapy is optimized in all patients based on the recommendations of the Heart Failure Society of America ("Usual Care"), and then randomized between 2 treatment groups; UC or EECP (35 hours over 7 weeks). CONCLUSION: Efficacy measures include standard exercise tolerance tests on a treadmill (modified Naughton protocol), with measurements of peak oxygen uptake and exercise duration time; quality of life questionnaires; NYHA classification; and neurohormonal markers of HF.

Counterpulsation↗

PubMed1985

Correlates and prognostic implication of exercise capacity in chronic congestive heart failure.

Previous studies have shown poor correlations between exercise tolerance and measurements of left ventricular (LV) function during rest in patients with congestive heart failure (CHF). To further evaluate the determinants of exercise tolerance and their relation to prognosis, we performed rest and exercise hemodynamic measurements and blood pool scintigraphy in 27 patients with CHF. All patients were treated with digitalis and diuretic drugs, but not vasodilator drugs. Exercise capacity was assessed by maximal oxygen consumption (VO2max) during upright bicycle ergometry. Both right ventricular (RV) and LV ejection fractions were measured by radionuclide techniques, and arterial, right atrial and pulmonary artery pressures, cardiac output, and derived hemodynamic indexes were determined. As a group, patients with severely impaired exercise tolerance (group 1, VO2max less than 10 ml/min/kg) had significantly higher rest pulmonary capillary wedge and right atrial pressures (30 +/- 4 vs 23 +/- 6 and 12 +/- 4 vs 7 +/- 2 mm Hg, respectively) than those with a VO2max of 10 to 18 ml/min/kg (group 2). They also had lower LV and RV ejection fractions (16 +/- 4% vs 21 +/- 4% and 19 +/- 12% vs 27 +/- 7%, respectively). However, overlap among individual patients was considerable, and only pulmonary capillary wedge pressure at rest correlated significantly (r = 0.69, p less than 0.001) with VO2max.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMedDate not supplied

[Effects of treatment with ACE and serotonin inhibitors on arterial blood pressure at rest and cycloergometric exercise and on systolic time intervals: comparison of enalapril and ketanserin].

Exercise tolerance test gives important diagnostic, prognostic and therapeutic information in hypertensive patients. One hundred essential hypertensive patients were treated with enalapril: 10 mg/day, ketanserin: 40 mg/day and associated enalapril: 5mg/day + ketanserin: 20 mg/day for three different periods of three months for each one, with a wash-out period of 15 days after each therapeutic cycle. We used ACE and ketanserin because they have a hypotensive effect without developing tolerance, metabolic effects, rebound events in case of sudden interruption. These pharmacologic agents, which are active by themselves, can also be used in association with other hypotensive agents. Two exercise tolerance tests were carried out on each patient before and after each therapeutic period. Clinostatic systolic time intervals were assessed before and after treatment. Enalapril and ketanserin reduced systolic and diastolic pressure in basal condition and after exercise tolerance test, without any interference on heart rate. The association of the two hypotensive agents resulted more active, even with a halved dose. The improving of the double product and the systolic time intervals confirm the efficacy of these treatments. Side effects were mild.

Adult↗

PubMedDate not supplied

Creatine use and exercise heat tolerance in dehydrated men.

CONTEXT: Creatine monohydrate (CrM) use is highly prevalent in team sports (eg, football, lacrosse, ice hockey) and by athletes at the high school, college, professional, and recreational levels. Concerns have been raised about whether creatine use is associated with increased cramping, muscle injury, heat intolerance, and risk of dehydration. OBJECTIVE: To assess whether 1 week of CrM supplementation would compromise hydration status, alter thermoregulation, or increase the incidence of symptoms of heat illness in dehydrated men performing prolonged exercise in the heat. DESIGN: Double-blind, randomized, crossover design. SETTING: Human Performance Laboratory. PATIENTS OR OTHER PARTICIPANTS: Twelve active males, age = 22 +/- 1 year, height = 180 +/- 3 cm, mass = 78.8 +/- 1.2 kg, body fat = 9 +/- 1%, V(O2)peak = 50.9 +/- 1 ml.kg(-1).min(-1). INTERVENTION(S): Subjects consumed 21.6 g.d(-1) of CrM or placebo for 7 days, underwent 48 +/- 10 days of washout between treatments, and then crossed over to the alternate treatment in the creatine group. On day 7 of each treatment, subjects lost 2% body mass by exercising in 33.5 degrees C and then completed an 80-minute exercise heat-tolerance test (33.5 degrees C +/- 0.5 degrees C, relative humidity = 41 +/- 12%). The test consisted of four 20-minute sequences of 4 minutes of rest, alternating a 3-minute walk and 1-minute high-intensity run 3 times, and walking for 4 minutes. MAIN OUTCOME MEASURES: Thermoregulatory, cardiorespiratory, metabolic, urinary, and perceptual responses. RESULTS: On day 7, body mass had increased 0.88 kg. No interaction or treatment differences for placebo versus CrM during the exercise heat-tolerance test were noted in thermoregulatory (rectal temperature, 39.3 +/- 0.4 degrees C versus 39.4 +/- 0.4 degrees C) cardiorespiratory (Vo(2), 21.4 +/- 2.7 versus 20.0 +/- 1.8 ml.kg(-1).min(-1); heart rate, 192 +/- 10 versus 192 +/- 11 beats.min(-1); mean arterial pressure, 90 +/- 9 versus 88 +/- 5 mm Hg), metabolic (lactate, 6.7 +/- 2.7 versus 7.0 +/- 3.0 mmol.L(-1)), perceptual thirst (thirst, 7 +/- 1 versus 7 +/- 1; thermal sensation, 8 +/- 2 versus 8 +/- 1; rating of perceived exertion, 17 +/- 3 versus 17 +/- 2), plasma glucose (0-20 minutes of exercise heat-tolerance, 6.5 +/- 1.2 versus 6.8 +/- 0.8 mmol.L(-1)), plasma (297 +/- 5 versus 300 +/- 4 mOsm.kg(-1)) and urine (792 +/- 117 versus 651 +/- 134 mOsm.kg(-1)), urine specific gravity (1.025 +/- 0.003 versus 1.030 +/- 0.005) and urine color (7 +/- 1 versus 6 +/- 1) measures were increased during CrM. Environmental Symptoms Questionnaire scores were similar between treatments. The levels of dehydration incurred during dehydration and the exercise heat-tolerance test were similar and led to similar cumulative body mass losses (-4.09 +/- 0.53 versus -4.38 +/- 0.58% body mass). CONCLUSIONS: Short-term CrM supplementation did not increase the incidence of symptoms or compromise hydration status or thermoregulation in dehydrated, trained men exercising in the heat.

Journal Article↗

PubMed1994

Central and peripheral limitations to upright exercise in untrained cardiac transplant recipients.

BACKGROUND: Functional capacity and quality of life are subjectively improved after cardiac transplantation. However, the objective improvement in exercise tolerance after transplantation has been disappointing. The extent to which allograft diastolic dysfunction contributes to this exercise intolerance has not been defined. METHODS AND RESULTS: Thirty cardiac transplant recipients between 3 and 16 months after transplantation and 30 age-matched normal control subjects underwent maximal symptom-limited graded upright bicycle exercise testing with simultaneous radionuclide angiography, invasive hemodynamic monitoring, and breath-by-breath gas analysis. Mean blood pressure was higher in the transplant group at supine rest (112.1 versus 97.7 mm Hg), normalized with upright posture, and became lower than normal at peak exercise (121.1 versus 133.2 mm Hg). Systolic function as measured by ejection fraction was normal in both groups. However, the cardiac transplant recipients had significantly lower exercise tolerance, achieving a mean maximal work rate of 390 kilopond-meters per minute (kpm/min), compared with 825 kpm/min in the normal subjects. Peak oxygen consumption was 12.3 mL.min-1.kg-1 in the transplant group, 46% lower than the normal group's value of 22.9 mL.min-1.kg-1. The transplant patients had a resting tachycardia (94 beats per minute) and a 79% reduction in exercise heart rate reserve compared with normal. Despite this chronotropic incompetence, stroke index response to exercise was consistently lower after transplantation, accounting for a 41% reduction in cardiac index at maximal exercise. The lower stroke index was accompanied by a 32% lower end-diastolic volume index at rest and a 14% lower end-diastolic volume index at peak exercise. Despite the smaller ventricular volumes after transplantation, pulmonary capillary wedge pressure was 35% higher than normal at supine rest and 50% higher at maximal exercise. Right atrial and mean pulmonary arterial pressures were similarly elevated. The ratio of pulmonary capillary wedge pressure to end-diastolic volume index was significantly higher during the postural change and exercise, suggesting allograft diastolic dysfunction. Arteriovenous oxygen difference was similar between groups at rest and with submaximal exercise but was 24% lower at maximal exercise in the transplant group, suggesting an abnormality in peripheral oxygen uptake or utilization. CONCLUSIONS: Exercise tolerance is severely limited during the first 16 months after cardiac transplantation despite preservation of allograft left ventricular systolic function. This intolerance is due to an inadequate cardiac index response from a combination of chronotropic incompetence and diastolic dysfunction limiting the appropriate compensatory use of the Starling mechanism. In addition, there is a peripheral abnormality in oxygen transport or utilization that may partially reflect the effects of deconditioning.

Adult↗