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PubMed1997

Long-term sequential changes in exercise capacity and chronotropic responsiveness after cardiac transplantation.

BACKGROUND: Peak exercise capacity improves early after orthotopic cardiac transplantation. However, the physiological response to exercise remains abnormal, with a reduced rate of heart rate (HR) rise and reductions in peak exercise HR and the increment in HR from rest to peak exercise. This chronotropic incompetence is due in large part to cardiac denervation. If reinnervation occurs after transplantation, it might result in an improvement in both chronotropic responsiveness and maximal exercise capacity. We therefore hypothesized that the chronotropic response to exercise and maximal exercise capacity would improve with time after transplantation. METHODS AND RESULTS: Peak symptom-limited cardiopulmonary exercise tests performed in 57 clinically stable cardiac transplant recipients (mean age, 45 +/- 2 years) serially for up to 5 years after transplantation and in 33 control subjects without heart disease were analyzed retrospectively. Pretransplantation exercise tests were also performed in 41 patients an average of 4.7 +/- 0.6 months before transplantation. At 1 year after transplantation, peak oxygen consumption was 16.6 +/- 0.9 mL.kg-1.min-1, reflecting a 43% increase versus pretransplantation. Nevertheless, compared with control subjects, maximal exercise capacity and the HR response to exercise were subnormal in transplant recipients. There were no further increases in peak exercise capacity, peak exercise HR, or the peak increment in HR with exercise up to 5 years after transplantation. CONCLUSIONS: One year after cardiac transplantation, peak exercise capacity and chronotropic responsiveness are subnormal. There is no further improvement in peak exercise capacity or chronotropic responsiveness as late as 5 years after transplantation. These data indicate that with regard to chronotropic responsiveness, functionally significant cardiac reinnervation does not occur between the first and fifth years after transplantation.

Adult↗

PubMed1999

Exercise-induced rise in arterial potassium in patients with chronic heart failure.

OBJECTIVES: In patients with chronic heart failure (CHF), exercise is frequently associated with skeletal muscle fatigue and breathlessness due to heightened ventilatory response. The exercise-induced rise in potassium, which is released from the exercising skeletal muscle, has been implicated in ventilatory control during exercise. The aim of the present study was to determine whether the exercise-induced rise in arterial potassium is altered in patients with CHF and to examine the relationship between increased exercise ventilation and exercise-induced hyperkalemia in patients with CHF. METHODS AND RESULTS: We evaluated 88 patients with CHF (25 patients were in class I, 35 in class II, and 28 in class III according to the New York Heart Association functional classification) and 14 normal subjects. Subjects performed symptom-limited ergometer exercise while expired gas, arterial blood gas, and arterial potassium were analyzed. The increases in ventilation (deltaV(E)), effective alveolar ventilation (deltaVA), and carbon dioxide output (deltaV(CO2)) from rest to peak exercise decreased as the severity of CHF advanced. The ratio of deltaV(E) to deltaV(CO2) was significantly elevated in class III patients, although there was no difference in the ratio of deltaVA to deltaV(CO2) among the four groups. Rest and exercise arterial P(CO2) did not differ among the four groups and was controlled within the normal range. The increase in arterial potassium (deltaK+) from rest to peak exercise was markedly reduced as the severity of CHF advanced: (mean +/- SD) 1.70+/-0.32 mmol/L in normal subjects; 1.46+/-0.27 mmol/L in class I patients; 1.15+/-0.24 mmol/L in class II patients; and 0.78+/-0.24 mmol/L in class III patients. The ratios of deltaVA or deltaV(CO2) to deltaK+ were not different among the four groups. The ratio of deltaV(E) to deltaK+, however, was significantly greater in patients in class III than in normal subjects or patients in class I or II. CONCLUSIONS: The deltaK+ from rest to peak exercise was markedly reduced as the severity of CHF advanced. The increased exercise ventilation due to increased physiologic dead space in severe CHF was not accompanied by the corresponding augmentation of exercise-induced hyperkalemia. Exercise-induced hyperkalemia does not contribute to the increased ventilatory drive to keep normal arterial P(CO2) during exercise in the presence of increased physiologic dead space in severe CHF.

Exercise↗

PubMedDate not supplied

Left ventricular systolic function and diastolic filling at rest and during upright exercise after orthotopic heart transplantation: comparison with young and aged normal subjects.

To evaluate the hemodynamic response to upright exercise of heart transplant recipients, we had 10 patients aged 46 +/- 14 years undergo rest and exercise radionuclide ventriculography 6 to 26 (mean, 14) month after orthotopic heart transplantation. Results were compared with those obtained in 18 young subjects, aged 22 +/- 3 years, and 17 older subjects, aged 56 +/- 5 years. Radionuclide ventriculography was performed at rest and at three levels of exercise, representing 50%, 70%, and 90% of the maximal physical workload. At rest, heart rate was higher in transplant patients than in normal subjects, but during exercise, heart rate increased only 33% compared with a 142% increase in the young subjects and a 111% increase in the older group. During exercise, left ventricular ejection fraction increased in the three groups, but, as compared with the transplant group, the increase of ejection fraction was higher in the young group. End-diastolic volume increased both in transplant patients (+16%) and in older subjects (+13%), whereas it decreased (-20%) in the young subjects during exercise. End-systolic volume decreased in the young group and in the transplant group with exercise, and it did not change in the older group. Cardiac index increased throughout the three levels of exercise in the three groups of subjects, but cardiac index was higher during exercise in young and older normal subjects. With exercise, all three groups showed increases in peak filling rates, but young subjects had a significantly higher value compared with the transplant group. Filling fraction in the first third of diastole did not change with exercise in the transplant and the older group but increased in the young group. We conclude that in transplant patients, increase in cardiac index during upright exercise is mediated by an increase in end-diastolic index during submaximal exercise and by increased heart rate and augmented contractility at peak exercise. Early diastolic filling is altered in these patients, and this alteration is independent from the changes in heart rate and cardiac volumes. When compared with normal persons, this pattern of hemodynamic response to exercise is similar to older subjects but differs from young subjects in whom the increase in heart rate and reduction in end-systolic volume are the chief mechanisms of enhancing cardiac index during exercise.

Adult↗

PubMed2000

Exercise and changes in health status in patients with ankylosing spondylitis.

BACKGROUND: Although exercise is a commonly recommended treatment for ankylosing spondylitis (AS), little is known about the effectiveness of unsupervised recreational and back exercises. We examined the effects of recreational exercise and back exercises on patient-reported pain severity, stiffness severity, and functional disability in a prospective longitudinal study of 220 patients with AS. METHODS: Participants provided information on exercise habits and health status every 6 months using mailed questionnaires (median follow-up, 4.5 years). Pain severity and stiffness severity were measured using visual analog scales, and functional disability was measured using the Health Assessment Questionnaire (HAQ) Disability Index. RESULTS: Among all patients, there were no associations between either the number of exercise minutes per week or the number of days of back exercise per week and short-term (6-month) changes in pain, stiffness, or HAQ Disability Index. However, among those who had AS for 15 years or less, pain scores were 0.18 points lower (on a scale of 0-3; P =.04), and stiffness scores were 6.4 points lower (on a scale of 0-100; P =.005) during periods with more than 200 minutes per week of exercise compared with periods with 0 to 30 minutes of exercise per week. Among those who had AS for more than 15 years, pain scores were 0.11 points lower (on a scale of 0-3; P =. 03), and HAQ Disability Indexes were 0.08 points lower (on a scale of 0-3; P<.001) during periods with 5 to 7 days per week of back exercise compared with periods when back exercises were not performed. Less intense levels of exercise were not associated with improvements in health status. CONCLUSIONS: Unsupervised recreational exercise improves pain and stiffness, and back exercise improves pain and function in patients with AS, but these effects differ with the duration of AS. Health status is improved when patients perform recreational exercise at least 30 minutes per day and back exercises at least 5 days per week. Arch Intern Med. 2000;160:2969-2975

Adult↗

PubMed2000

Testosterone replacement and resistance exercise in HIV-infected men with weight loss and low testosterone levels.

CONTEXT: Previous studies of testosterone supplementation in HIV-infected men failed to demonstrate improvement in muscle strength. The effects of resistance exercise combined with testosterone supplementation in HIV-infected men are unknown. OBJECTIVE: To determine the effects of testosterone replacement with and without resistance exercise on muscle strength and body composition in HIV-infected men with low testosterone levels and weight loss. DESIGN AND SETTING: Placebo-controlled, double-blind, randomized clinical trial conducted from September 1995 to July 1998 at a general clinical research center. PARTICIPANTS: Sixty-one HIV-infected men aged 18 to 50 years with serum testosterone levels of less than 12.1 nmol/L (349 ng/dL) and weight loss of 5% or more in the previous 6 months, 49 of whom completed the study. INTERVENTIONS: Participants were randomly assigned to 1 of 4 groups: placebo, no exercise (n = 14); testosterone enanthate (100 mg/wk intramuscularly), no exercise (n = 17); placebo and exercise (n = 15); or testosterone and exercise (n = 15). Treatment duration was 16 weeks. MAIN OUTCOME MEASURES: Changes in muscle strength, body weight, thigh muscle volume, and lean body mass compared among the 4 treatment groups. RESULTS: Body weight increased significantly by 2.6 kg (P<.001) in men receiving testosterone alone and by 2.2 kg (P = .02) in men who exercised alone but did not change in men receiving placebo alone (-0.5 kg; P = .55) or testosterone and exercise (0.7 kg; P = .08). Men treated with testosterone alone, exercise alone, or both experienced significant increases in maximum voluntary muscle strength in leg press (range, 22%-30%), leg curls (range, 18%-36%), bench press (range, 19%-33%), and latissimus pulls (range, 17%-33%). Gains in strength in all exercise categories were greater in men assigned to the testosterone-exercise group or to the exercise-alone group than in those assigned to the placebo-alone group. There was a greater increase in thigh muscle volume in men receiving testosterone alone (mean change, 40 cm3; P<.001 vs zero change) or exercise alone (62 cm3; P = .003) than in men receiving placebo alone (5 cm3; P = .70). Average lean body mass increased by 2.3 kg (P = .004) and 2.6 kg (P<.001), respectively, in men who received testosterone alone or testosterone and exercise but did not change in men receiving placebo alone (0.9 kg; P = .21). Hemoglobin levels increased in men receiving testosterone but not in those receiving placebo. CONCLUSION: Our data suggest that testosterone and resistance exercise promote gains in body weight, muscle mass, muscle strength, and lean body mass in HIV-infected men with weight loss and low testosterone levels. Testosterone and exercise together did not produce greater gains than either intervention alone.

Adult↗

PubMed2005

Exercise therapy for multiple sclerosis.

BACKGROUND: No intervention has proven effective in modifying long-term disease prognosis in Multiple Sclerosis (MS) but exercise therapy is considered to be an important part of symptomatic and supportive treatment for these patients. OBJECTIVES: To assess the effectiveness of exercise therapy for patients with MS in terms of activities of daily living and health-related quality of life. SEARCH STRATEGY: We searched the Cochrane MS Group Specialised Register (searched: March 2004), Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 2, 2004), MEDLINE (from 1966 to March 2004), EMBASE (from 1988 to March 2004 ), CINAHL (from 1982 to March 2004), PEDro (from 1999 to March 2004) . Manual search in the journal 'Multiple Sclerosis' and screening of the reference lists of identified studies and reviews. We also searched abstracts published in proceedings of conferences. SELECTION CRITERIA: Randomised Controlled Trials (RCTs) that reported on exercise therapy for adults with MS, not presently experiencing an exacerbation; outcomes that include measures of activity limitation or health-related quality of life or both. DATA COLLECTION AND ANALYSIS: Two reviewers independently extracted data and methodological quality of the included trials. Disagreements were resolved by discussion. The results were analysed using a best-evidence synthesis based on methodological quality. MAIN RESULTS: Nine high-methodological-quality RCTs(260 participants) met the inclusion criteria. Six trials focussed on comparison of exercise therapy versus no exercise therapy, whereas three trials compared two interventions that both met our definition of exercise therapy. Best evidence synthesis showed strong evidence in favour of exercise therapy compared to no exercise therapy in terms of muscle power function, exercise tolerance functions and mobility-related activities. Moderate evidence was found for improving mood. No evidence was observed for exercise therapy on fatigue and perception of handicap when compared to no exercise therapy. Finally, no evidence was found that specific exercise therapy programmes were more successful in improving activities and participation than other exercise treatments. No evidence of deleterious effects of exercise therapy was described in included studies. AUTHORS' CONCLUSIONS: The results of the present review suggest that exercise therapy can be beneficial for patients with MS not experiencing an exacerbation. There is an urgent need for consensus on a core set of outcome measures to be used in exercise trials. In addition, these studies should experimentally control for 'dose' of treatment, type of MS and should include sufficient contrast between experimental and control groups.

Exercise Therapy↗

PubMed2006

An update on the definition of "excessive exercise" in eating disorders research.

OBJECTIVE: The current study informed the definition of "excessive exercise" by examining relations between exercise behavior, eating-disordered behavior, and quality of life (QOL) in a community sample of women. METHOD: Self-report measures of frequency of exercise, obligatory exercise and motivation for exercise, and of eating disorder psychopathology and QOL, were completed by 3,472 women aged 18-42 years who engaged in regular exercise. RESULTS: The extent to which exercise is intended to influence weight or shape and the degree to which guilt is experienced when exercise is postponed were the exercise variables most strongly associated with elevated levels of eating disorder psychopathology and reduced QOL. Subgroups of participants who reported exercising solely for weight and shape reasons (n = 322 [9.3%]), intense guilt after postponement of exercise (n = 136 [3.9%]), or both (n = 116 [3.3%]), had markedly elevated levels of eating disorder psychopathology. There was no association between excessive exercise and reduced QOL after the effects of eating disorder psychopathology were statistically controlled. CONCLUSION: The findings suggest that exercise is excessive when its postponement is accompanied by intense guilt or when it is undertaken solely to influence weight or shape. Operational definitions of excessive exercise might usefully include reference to these terms. The findings may also be of benefit in informing the content of prevention programs, which address dysfunctional exercise behavior. Excessive exercise is unlikely to be associated with impairment in psychosocial functioning in the absence of eating disorder psychopathology. It may, however, be a useful indicator of such psychopathology.

Activities of Daily Living↗

PubMed2004

Predictors of adherence and contamination in a randomized trial of exercise in colorectal cancer survivors.

The purpose of this study was to examine predictors of exercise adherence (i.e. exercise in the intervention group) and exercise contamination (i.e. exercise in the control group) in a randomized controlled trial of home-based exercise in colorectal cancer survivors. At baseline, 102 participants completed measures of the theory of planned behavior, personality, past exercise, exercise stage of change, physical fitness, and medical/demographics and then were randomly assigned in a 2:1 ratio to an exercise (n=69) or control (n=33) group. Exercise was monitored weekly for 16 weeks using self-reports by telephone. Ninety-three (91%) participants completed the trial. Adherence was 76% in the exercise group and contamination was 52% in the control group. Hierarchical stepwise regression analyses indicated that baseline exercise stage of change (beta=0.35; p=0.001), employment status (beta=-0.28; p=0.010), treatment protocol (beta=-0.26; p=0.018), and perceived behavioral control (beta=0.20; p=0.055) explained 39.6% of the variance in exercise adherence. Intentions (beta=0.36; p=0.049) and baseline exercise stage of change (beta=0.30; p=0.095) explained 29.9% of the variance in exercise contamination. These findings may have implications for conducting clinical trials of exercise in colorectal cancer survivors and for promoting exercise to colorectal cancer survivors outside of clinical trials.

Colorectal Neoplasms↗

PubMed2002

Effects of resistance exercise volume and nutritional supplementation on anabolic and catabolic hormones.

Seven resistance-trained men performed six bouts of resistance exercise, each separated by at least 1 week, in a crossover design. High, moderate and low volumes of exercise were used, each performed twice and followed immediately post-exercise by either a placebo or carbohydrate-protein supplementation. All bouts of resistance exercise were performed using a load equal to 100% of each subject's ten-repetition maximum (10-RM), and all rest periods between sets of exercise were 1 min. Blood was obtained before and at intervals after exercise until 120 min post-exercise. Lactate levels were significantly (P < 0.05) elevated immediately post-exercise, and to a significantly greater extent after the greatest volume of exercise. Levels of growth hormone rose significantly after the greatest volume of exercise only. Those of insulin and glucose rose significantly after supplementation only. Cortisol levels tended to be higher after the greatest volume of exercise, but the differences were not significant. Supplementation had no effect on the lactate, growth hormone or cortisol responses to resistance exercise. The data indicate that volume of exercise and protein-carbohydrate supplementation can alter the metabolic and hormonal responses to resistance exercise independently. However, cortisol levels remain high after a high volume of resistance exercise, irrespective of whether a post-exercise carbohydrate-protein supplement is used.

Adult↗

PubMed2003

Oxidation of [13C]glucose ingested before and/or during prolonged exercise.

Ingestion of glucose before exercise results in a transient increase in plasma insulin concentrations. We hypothesized that if glucose was also ingested during the exercise period the elevated plasma insulin concentration could increase exogenous glucose oxidation. The oxidation rate of glucose ingested 30 min before (50 g) and/or during (110 or 160 g in fractionated doses) exercise [120 min; 67.3 (1.2)% maximal O(2) uptake] was studied on six young male subjects, using (13)C-labelling. Ingestion of glucose before exercise significantly increased plasma insulin concentration [from 196 (45) to 415 (57) pmol l(-1)] but the value returned to pre-exercise level within the first 30 min of exercise in spite of a continuous increase in plasma glucose concentration. Ingestion of glucose 30 min before exercise did not increase the oxidation of exogenous glucose between minutes 30 and 60 during the exercise period [0.36 (0.03) vs 0.30 (0.02) g min(-1), when placebo or unlabelled glucose was ingested respectively]. Over the last 90 min of exercise, when glucose was ingested only during exercise, 49.2 (3.1) g [0.55 (0.04) g min(-1)) was oxidized, while when it was ingested both before and during exercise, 65.7 (4.6) g [0.73 (0.05) g min(-1)] was oxidized [26.7 (2.1) g of the 50 g ingested before exercise but only 39.0 (2.4) g of the 110 g ingested during the exercise period]. Thus, ingestion of glucose 30 min before the beginning of exercise did not enhance the oxidation rate of exogenous glucose ingested during the exercise period, although the total amount of exogenous glucose oxidized was larger than when ingested only during the exercise period.

Administration, Oral↗

PubMed2004

Specificity and functional impact of post-exercise depression of cortically evoked motor potentials in man.

Magnetic stimulation of the motor cortex with electromyographic recordings from exercising muscles has shown corticospinal excitability to be depressed following exercise. We now investigate whether this depression spreads to non-exercising muscles and its influence on performance. Healthy volunteers made unilateral biceps curls to exhaustion and, in another later session, for 25% of the time to exhaustion. Bilateral motor-evoked potentials (MEPs) in biceps brachii and first dorsal interosseus muscles were measured at 2-min intervals before and after exercise. In another experiment, subjects performed exhaustive curls and, in addition to MEP areas, force production in biceps, hand-grip force, simple reaction times and movement times were measured bilaterally. MEPs were depressed after exhaustive exercise in the exercising biceps for over 60 min; depression was also observed 10-15 min after exercise in the non-exercising biceps but not in the first dorsal interosseus of either hand. The shorter exercise period produced depression of MEPs only in the exercising muscle. After exhaustive exercise maximum voluntary contraction fell in the exercising biceps and this correlated with MEP areas. No reduction in force was seen in the non-exercising biceps but hand-grip force fell slightly in both arms. There was no change in reaction times or movement times. Depression of MEPs can occur in non-exercising homonymous muscles but not in heteronymous muscles and only when exercise levels are high. There was no measurable functional deficit in the non-exercising limb, so we conclude that the reduced corticospinal excitability observed in this limb has little or no consequence on the performance parameters measured.

Adaptation, Physiological↗

PubMed2006

Effect of single-leg resistance exercise on regional arterial stiffness.

To examine the effects of lower-limb unilateral resistance exercise on central and peripheral arterial stiffness, thirteen participants (7 male and 6 female, mean age = 21.5 +/- 0.7 years) performed leg press exercise using their dominant leg. Pulse wave velocity (PWV) was used to measure central (carotid to femoral) and peripheral (femoral to dorsalis pedis of both legs) arterial stiffness before, 5 min post, and 25 min post exercise. No change was found in central PWV. A leg-by-time interaction was found as peripheral PWV in the non-exercised leg did not change (7.9 +/- 0.3 m/s to 7.9 +/- 0.3 m/s to 8.0 +/- 0.3 m/s, P = 0.907) while peripheral PWV in the exercised leg significantly decreased from pre (8.7 +/- 0.4 m/s) to 5 min post exercise (7.5 +/- 0.3 m/s, P = 0.008) and 25 min post exercise (7.8 +/- 0.3 m/s, P = 0.031). Systolic blood pressure (BP) increased significantly from pre (126.9 +/- 3.4 mmHg) to 5 min post exercise (133.7 +/- 4.3 mmHg, P = 0.023) and was not different than resting values 25 min post exercise (123.2 +/- 3.1 mmHg). There was no change in diastolic BP. Compared to heart rate (HR) pre-exercise (55.4 +/- 1.4 bpm), HR was significantly increased 5 min post exercise (70.7 +/- 3.0 bpm, P = 0.001) and 25 min post exercise (69.1 +/- 2.0, P = 0.001). Acute resistance exercise appears to decrease arterial stiffness in the exercised leg while having no effect on central arterial stiffness or arterial stiffness of the non-exercised leg. These findings suggest that regional changes rather than systemic alterations may influence arterial stiffness following acute resistance exercise.

Adult↗

PubMed1997

Effects of isokinetic, isotonic and isometric submaximal exercise on heart rate and blood pressure.

The purpose of the present study was to compare arterial pressure (AP) and heart rate (HR) responses to submaximal isokinetic, isotonic and isometric exercises currently employed in physical rehabilitation therapy in terms of both magnitude and time-course. To this aim AP and HR were continuously and noninvasively measured in ten healthy subjects performing isokinetic, isotonic and isometric exercises at the same relative intensity. Isokinetic and isotonic exercises consisted of 30 knee extension/flexion repetitions at 40% of maximal effort. Isokinetic speed was set at 180 degrees s(-1). Isometric exercise consisted of a 60-s knee extension at 40% maximal voluntary contraction. The AP showed a rapid and marked increase from the onset of all types of exercise progressing throughout the exercises. Peak systolic (SAP) and diastolic (DAP) arterial pressure were 190.7 (SEM 8.9) and 121.6 (SEM 7.8) mmHg during isokinetic and 197.6 (SEM 11.2) and 128.3 (SEM 7.7) mmHg during isotonic exercise, respectively. During isometric exercise peak SAP and DAP were 168.1 (SEM 6.3) and 102.1 (SEM 3.7) mmHg, respectively [both lower compared to isokinetic and isotonic exercise (P < 0.05)]. The HR rose abruptly and after five isokinetic and isotonic repetitions it had already increased by about 30 beats min(-1), continuing to rise throughout the exercises. The HR response to isometric exercise was significantly less (P < 0.05) at all times. An immediate fall in AP, undershooting resting levels, was observed at the cessation of all types of exercise, being more marked after isokinetic and isotonic exercise. These results indicate that submaximal exercise of a dynamic type induces greater AP responses than intensity-matched isometric exercise and that even submaximal endurance-type rehabilitation exercise yields an elevated functional stress on the cardiovascular system which could precipitate hazardous events particularly in subjects with unrecognized cardiac diseases.

Adult↗

PubMed1978

Submaximal exercise testing after acute myocardial infarction: myocardial scintigraphic and electrocardiographic observations.

The relation between global and regional left ventricular function and electrocardiographic signs of ischemia at rest and during submaximal supine exercise was studied in 27 patients 2 to 3 weeks after acute myocardial infarction. Dynamic myocardial scintigraphy was performed at rest and during submaximal exercise utilizing an in vivo method of labeling red blood cells with technetium-99m pertechnetate. Gated radionuclide blood pool scintigrams were obtained in a modified left anterior oblique, and in some patients also in the right anterior oblique projection, to measure left ventricular ejection fraction and segmental wall motion. Electrocardiographic monitoring of heart rate and rhythm was provided during the exercise. The submaximal exercise test was terminated when the patient's heart rate reached 125 beats/min or if angina, malignant ventricular ectopy or electrocardiographic evidence of myocardial ischemia developed before this rate was reached. The data demonstrate that patients with a recent anterior myocardial infarct, in contrast to patients with a recent inferior or nontransmural infarct, manifest a significant reduction in left ventricular ejection fraction with submaximal exercise. Of the eight patients with an anterior infarct, seven had segmental wall motion abnormalities at rest. Four of these eight manifested more severe abnormalities with submaximal exercise; three had abnormalities at rest that did not change with exercise. Four of the eight had a positive electrocardiographic response during exercise (two were taking digoxin). Of these four, only two had more marked wall motion abnormalities with effort. Of the 13 patients with an inferior infarct, 11 had apparently normal wall motion in the modified left anterior oblique projection at rest, including 2 who manifested segmental wall motion abnormalities with submaximal exercise; the 2 remaining patients had wall motion abnormalities at rest that, on exercise, became more marked in one and were unchanged in one. Four of the 13 had a positive electrocardiographic response with exercise (one was taking digoxin); only one of these had a detectably more severe wall motion abnormality with exercise. Of the six patients with a nontransmural infarct, four had no identifiable wall motion abnormalities at rest; in one of these, an abnormality developed with exercise. The remaining two patients had wall motion abnormalities at rest; in one, a positive electrocardiographic ischemic response developed with exercise. Patients with an anterior infarct appear to have a different functional ventricular response to submaximal exercise at the time of hospital discharge than patients with an inferior or nontransmural infarct. To identify ischemic responses with submaximal exercise in these patients one should ideally use both electrocardiographic monitoring and dynamic myocardial scintigraphy.

Adult↗

PubMed1986

Studies of Doppler aortic flow velocity during supine bicycle exercise.

Although Doppler echocardiography is useful in the assessment of left ventricular function at rest, little information is available on the application of this technique during exercise. Consequently, Doppler aortic flow studies were performed in 17 young normal subjects during and after supine bicycle exercise. The purposes of the study were to determine the feasibility of recording Doppler aortic flow velocity with a suprasternal notch transducer during exercise and to assess the changes in normal aortic flow velocity parameters during exercise and early recovery. Each subject exercised until fatigue; mean duration of exercise was 10 minutes. Heart rate increased from a mean of 69 beats/min at control to 159 beats/min at peak exercise. On average, aortic peak flow velocity increased by 45% from control, reaching its maximum at 2 minutes after exercise. Ejection time decreased by 34% during exercise, being shortest at peak exercise. Heart rate, peak flow velocity and ejection time had not returned to normal by 10 minutes after exercise. Aortic flow velocity integral (a relative measure of stroke volume) decreased by 10% at peak exercise (p less than 0.05) compared with control, but had returned to control at 2 minutes after exercise. Despite mild aliasing, increased spectral dispersion, faster heart rates and increased respiratory rate during maximal exercise, aortic flow velocity measurements could be recorded using the suprasternal technique. These baseline Doppler exercise data should be useful in further studies of exercise hemodynamic changes in patients with heart disease.

Adolescent↗

PubMed1991

Interpreting results of exercise studies after acute myocardial infarction altered by thrombolytic therapy, coronary angioplasty or bypass.

Numerous studies have assessed the ability of exercise modalities to predict patient outcome after acute myocardial infarction (AMI). Implicit in the use of these prior data to assess the prognosis of patients currently undergoing exercise studies is the assumption that patients selected for exercise assessment are similar over time and that the data generated in the past are therefore applicable to the current patient populations. This study retrospectively assessed the clinical, exercise, and rest and exercise radionuclide angiographic data in 791 consecutive patients referred for exercise radionuclide angiography within 1 month after AMI during a 5-year period to determine if the clinical and exercise characteristics of patients referred for exercise evaluation after infarction have changed significantly over time. Most parameters examined demonstrated significant increasing trends, including thrombolytic therapy at the time of AMI, revascularization procedure between AMI and exercise assessment, age, beta-blocker usage, Q-wave AMI, inferior infarction, exercise double product, exercise capacity, significant ST-segment depression with exercise, peak ejection fraction, and change in ejection fraction with exercise. These data indicate that the characteristics of patients selected to undergo exercise after AMI in a large referral center have changed significantly over time. If these data are applicable to other referral centers and to other exercise testing modalities, previously published results regarding exercise assessment after AMI will need to be reconfirmed in patients currently selected for testing, since these results may no longer be applicable in this current era of aggressive medical and interventional management.

Angioplasty, Balloon, Coronary↗

PubMedDate not supplied

Variable effects of exercise intensity on reduced glutathione, thiobarbituric acid reactive substance levels, and glucose concentration.

BACKGROUND: Physical exercise may be associated with a 10- to 20-fold increase in whole body oxygen uptake. Generation of free oxygen radicals (FORs) is elevated to a level that overwhelms tissue antioxidant defense systems in exercise. One of the most reliable indices of exercise-induced oxidant production is tissue glutathione oxidation. METHODS: In this study three different volunteer groups carried out various sports disciplines and worked at least as amateurs for 6-7 years before and after aerobic (Aer)-, anaerobic (Anae)-, or aerobic + anaerobic (Aer-Anae)-dominant exercises. Thiobarbituric acid reactive substances (TBARS) reduced glutathione (GSH) levels, glucose concentration was measured, and we investigated their relationships with different types of exercise. From all groups (n=60, each group comprising 10 females and 10 males), we collected blood samples at the following five different times: before exercise; immediately after exercise, and 4, 24, and 48 h after completion of exercise. These samples were assayed for whole blood GSH, plasma TBARS levels, and glucose concentration. RESULTS: Significant increase in Aer-Anae was noted in levels of TBARS while decrease was observed in glutathione levels in exercise group as compared with prior levels in all groups. However, no statistical difference was observed in total group levels before and after exercise and in male and female groups compared before and after exercise. When gender differences were taken into account, females generally had higher levels of GSH, whereas TBARS levels were higher in males. When compared either before or after exercise, levels of glucose concentration--especially immediately after exercise period in all groups--were higher. In addition, in Anae groups glucose concentrations were higher at 4 and 24 h in females than in males. Aer exercise caused oxidative stress to a lesser degree, whereas Aer-Anae exercise caused oxidative stress of higher degree that was statistically significant. CONCLUSIONS: According to our findings, exercise increased TBARS level significantly in all groups, especially more so in Aer-Anae groups. In addition, GSH was increased more in females than in males, while concentration of glucose did not change remarkably. Additionally, it can be stated that women are more resistant to oxidative stress.

Adult↗

PubMed2006

Effects of exercise on adiponectin and adiponectin receptor levels in rats.

Adiponectin reportedly reduces insulin-resistance. Exercise has also been shown to lessen insulin-resistance, though it is not known whether exercise increases levels of adiponectin and/or its receptors or whether its effects are dependent on exercise intensity and/or frequency. Catecholamine levels have been shown to increase during exercise and to fluctuate based on exercise intensity and duration. In light of this information, we examined the effects of exercise on catecholamine, adiponectin, and adiponectin receptor levels in rats. Our data showed that blood adiponectin levels increased by 150% in animals that exercised at a rate of 30 m/min for 60 min 2 days per week, but not 5 days, per week; no such increase was observed in rats that exercised at a rate of 25 m/min for 30 min. The effects of exercise on adiponectin receptor mRNA were variable, with adiponectin receptor 1 (AdipoR1) levels in muscle increasing up to 4 times while adiponectin receptor 2 (AdipoR2) levels in liver fell to below half in response to exercise at a rate of 25 m/min for 30 min 5 days per week. We also observed that urinary epinephrine levels and plasma lipids were elevated by exercise at a rate of 25 m/min for 30 min 2 days per week. Exercise frequency at a rate of 25 m/min for 30 min correlated with AdipoR1 and AdipoR2 mRNA expression in the muscle and liver, respectively (r=0.640, p<0.05 and r=-0.808, p<0.0005, respectively). Urinary epinephrine levels correlated with AdipoR2 mRNA expression in liver tissues (r=-0.664, p<0.05) in rats that exercised at a rate of 25 m/min for 30 min. Thus, exercise may regulate adiponectin receptor mRNA expression in tissues, which might cause increases in glucose uptake and fatty acid oxidation in the muscle. The effect of exercise on adiponectin levels depends on the specific conditions of the exercise.

Adiponectin↗