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PubMed1992

Effects of chronic intense exercise training on the leukocyte response to acute exercise.

Circulatory leukocytes vary significantly in response to acute bouts of exercise. However, little is known concerning the adaptability of this response to chronic intense exercise training. We investigated the circulating leukocytic response to acute exercise in trained athletes during a 28-day intense exercise training program. On day 0, 14, 28 and two days after cessation of the increased training, eight trained male athletes (VO2max greater than 60 ml.kg-1.min-1) were subjected to a 20-km bicycle ergometer time trial. Blood samples were drawn before (PRE, for resting baseline values) and five minutes after (POST, response to acute exercise) the time trial. Beginning on day 0, athletes were instructed to increase the duration of their training 50%. The intense exercise training, which lasted 28 days, was verified weekly. Acute bouts of exercise caused a significant increase (p less than 0.05) in circulating white blood cells, lymphocytes, polymorphonuclear neutrophils and monocytes. The baseline resting values and the magnitude of the response to the acute bouts of exercise in the above parameters were not different during the 28 days of chronic intense exercise training or 2 days after cessation of training as compared to the values observed on day 0. Similarly there was a significant increase (p less than 0.05) in cortisol levels in response to the acute bouts of exercise during the chronic intense exercise training, but the increases were not different from that observed under baseline conditions. These results lead to the conclusion that chronic intense exercise training does not alter the circulating leukocytic response to acute exercise.

Analysis of Variance↗

PubMed2003

Rationale for use of an exercise end point and design for the ADVANCE (A Dose evaluation of a Vasopressin ANtagonist in CHF patients undergoing Exercise) trial.

BACKGROUND: Exercise intolerance is a primary characteristic of chronic congestive heart failure. Exercise testing is therefore widely used to evaluate the degree of functional impairment, prognosis of underlying cardiac disease, and response to treatment. Historically, studies that used exercise tolerance as an end point to evaluate the efficacy of pharmacologic interventions have been confounded by methodologic differences involving protocols, exercise end points, absence or misuse of gas exchange data, and study design. METHODS: The purpose of this study was to outline the methodology and rationale of a unique cardiopulmonary exercise trial. The design was based on prior experience from evaluation of ACE inhibitors and other interventions. The ADVANCE (A Dose evaluation of a Vasopressin ANtagonist in CHF patients undergoing Exercise) trial is a multicenter, double-blind, placebo-controlled, randomized trial investigating the effects of a vasopressin antagonist, conivaptan, on functional capacity in patients with heart failure. RESULTS: The primary end point is change in the exercise time to reach 70% of peak oxygen consumption during an incremental exercise test. Secondary end points include changes in peak oxygen consumption and other exercise parameters as well as quality-of-life indicators. The study incorporates several unique features to lessen potential methodological errors of exercise testing in heart failure, including use of a core laboratory to evaluate exercise tests, a computer program to determine the exercise end points, and validation of each site before patient enrollment. CONCLUSIONS: The results of this study will have value not only for the further use of vasopressin antagonists for heart failure therapy but also for the use of exercise testing and gas exchange determination for the evaluation of new drug therapies.

Administration, Oral↗

PubMed1979

Serial exercise thallium myocardial perfusion scanning and exercise electrocardiography in the diagnosis of coronary artery disease.

Serial exercise thallium-201 myocardial perfusion scanning (exercise and 4-hour redistribution) was compared to rest and exercise electrocardiography (ECG) for the detection of coronary artery disease in 125 patients with known or suspected coronary artery disease. All patients underwent coronary arteriography and 108 were found to have significant coronary artery lesions. The serial exercise thallium scan was significantly more sensitive than rest and exercise ECG in detecting coronary artery disease (94% v. 83% P less than 0.01). The sensitivity of a reversible thallium perfusion scan abnormality and a positive exercise ECG for detecting exercise induced myocardial ischaemia in coronary artery disease was similar (69% v. 63%). The exercise thallium scan complemented the exercise ECG, and the sensitivity of the combined test was significantly greater than the exercise ECG alone (84% v. 63% P less than 0.001). The specificity for coronary artery disease of the exercise ECG was 65% and that of the exercise thallium-201 myocardial perfusion scan was 82% (P = NS). Thallium-201 myocardial perfusion scanning complements the rest and exercise ECG in the non-invasive detection of coronary artery disease.

Adult↗

PubMed1992

Effect of prior exercise in Pi/PC ratio and intracellular pH during a standardized exercise. A study on human muscle using [31P]NMR.

Seven subjects underwent a standard localized exercise of calf muscles in order to investigate whether the metabolic exercise-induced steady-state, as revealed by the evaluation of inorganic phosphate/phosphocreatine ratio, depends on the conditioning of the muscle just prior to the exercise. The experimental protocols consisted of two separate experiments using first [31P]nuclear magnetic resonance spectroscopy and second (on 3 subjects) infrared oxyphotometry to respectively follow variation of energy metabolism and tissular deoxygenation. The exercise consisted of 240 successive plantar flexions (0.5 Hz frequency) against a high load equivalent to 80% of the maximal voluntary contraction. This exercise was accomplished before cold exercise and after warm exercise, a warming-up period bringing to approximately 50% of VO2max. The results showed that: (1) steady-state level of phosphate/phosphocreatine and intracellular acidosis was significantly lowered by warming-up; (2) cold and warm exercise steady-state of calculated adenosine diphosphate values were not significantly different; (3) cold exercise rapidly induced a high tissular deoxygenation that is not observed during warm exercise; and (4) time-constant of phosphocreatine resynthesis is lowered after warm exercise but the initial slope of time-evolution is not modified. Parallel experiments also showed that phosphate/phosphocreatine steady-state was not modified in comparison with warm exercise when the same power of exercise was reached by stepwise incrementation of the charge. From these results we postulate that a better tissue oxygenation due to a global or localized warming-up allows to reach the same mechanical performance with a lower decrease of PCr content, owing to a faster adjustment of oxidative metabolism during the transitional period.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗

PubMed1999

Pre- and post exercise echocardiography in horses performing treadmill exercise in cool and hot/humid conditions.

We hypothesised that exercise in a hot and humid environment would affect echocardiographic indices of cardiac dimensions and function more than exercise in a cool environment. M-mode echocardiograms were obtained in 5 clinically normal horses before, and at 0, 10, 30 and 60 min after a treadmill exercise test. The test was performed in a controlled environment at 20 degrees C/40% relative humidity (RH) and again at 30 degrees C/80% RH. All the horses completed the exercise test in cool conditions, but only one horse completed the exercise test in the hot/humid environment. The relaxation time index (RTI) correlated significantly and inversely with heart rate (HR). Heart rate was increased and RTI was decreased immediately after exercise in cool conditions. HR recovery appeared to be prolonged following exercise in hot/humid conditions. Post exercise RTI was significantly decreased in hot/humid environment. In hot/humid conditions, the left ventricular internal dimensions measured in diastole and systole (LVIDd, LVIDs) were reduced following exercise and continued to fall throughout the 60 min after exercise. The left ventricular fractional shortening (FS%) was lower than resting levels immediately after exercise in hot/humid conditions. Significant decreases were found in LVIDs and LVIDd, which may reflect a reduction in preload arising from dehydration or re-distribution of blood throughout the recovery period following exercise in the hot/humid environment. It was concluded that echocardiography was a useful tool in assessing cardiac responses to exercise in different climates.

Aerobiosis↗

PubMed2002

Muscle glycogen content and glucose uptake during exercise in humans: influence of prior exercise and dietary manipulation.

There are many factors that can influence glucose uptake by contracting skeletal muscle during exercise and although one may be intramuscular glycogen content, this relationship is at present not fully elucidated. To test the hypothesis that muscle glycogen concentration influences glucose uptake during exercise, 13 healthy men were studied during two series of experiments. Seven men completed 4 h of two-legged knee extensor exercise 16 h after reducing of muscle glycogen by completing 60 min of single-legged cycling (Series 1). A further six men completed 3 h of two-legged knee extensor exercise on two occasions: one after 60 min of two-legged cycling (16 h prior to the experimental trial) followed by a high carbohydrate diet (HCHO) and the other after the same exercise followed by a low carbohydrate diet (LCHO) (Series 2). Muscle glycogen was decreased by 40 % when comparing the pre-exercised leg (EL) with the control leg (CL) prior to exercise in Series 1. In addition, muscle glycogen was decreased by the same magnitude when comparing LCHO with HCHO in Series 2. In Series 1, glucose uptake was 3-fold higher in the first 60 min of exercise, in the presence of unchanged pre-exercise GLUT4 protein in EL compared with CL, suggesting that the lower glycogen, and not the exercise the day before, might have provided the stimulus for increased glucose uptake. Despite the same magnitude of difference in pre-exercise glycogen concentration when comparing Series 1 with Series 2, neither direct-nor isotopic tracer-determined glucose uptake was higher in LCHO compared with HCHO in Series 2. However, arterial concentrations of insulin and glucose were lower, while free fatty acids and adrenaline were higher in LCHO compared with HCHO. These data suggest that pre-exercise glycogen content may influence glucose uptake during subsequent exercise. However, this is only the case when delivery of substrates and hormones remains constant. When delivery of substrates and hormones is altered, the potential effect of glycogen on glucose uptake is negated.

Adult↗

PubMed1994

Oxygen uptake kinetics are determined by cardiac function at onset of exercise rather than peak exercise in patients with prior myocardial infarction.

BACKGROUND: Resting cardiac function does not necessarily affect exercise capacity. However, to determine whether it affects early dynamics of oxygen uptake (VO2) during exercise, we measured VO2 during a constant work rate and during incremental exercise testing in patients with a history of myocardial infarction. VO2 kinetics and exercise capacity were compared between patients with relatively high left ventricular ejection fractions (LVEF > or = 35%, group 1) and those with lower ejection fractions (LVEF < 35%, group 2). METHODS AND RESULTS: Forty patients with a history of prior myocardial infarction (age, 57 +/- 10 years) were monitored during 6 minutes of moderate constant work rate testing (40 +/- 8 W) and during symptom-limited incremental exercise testing with a cycle ergometer. VO2 was calculated from respired gas analysis on a breath-by-breath basis. Cardiac output determinations were made with a computerized cadmium telluride detector every 10 seconds during exercise. The VO2 time constant during constant work rate exercise was slower in group 2 (58.0 +/- 7.6 seconds) compared with group 1 (45.8 +/- 10.5 seconds, P = .0002), indicating slower kinetics in group 2. The time constant for the rise in cardiac output during exercise was also slower in patients with lower EFs (63.0 +/- 12.8 versus 50.0 +/- 12.2 seconds). However, there were no differences in exercise capacity parameters, such as the VO2 or cardiac output at peak exercise, obtained during incremental exercise testing among the two groups. CONCLUSIONS: The prolonged time constant of VO2, which is primarily determined during early parts of exercise, reflects delayed cardiac output response in patients with severely impaired LV function. The time constant of VO2 during submaximal constant work rate exercise can be used as a sensitive and discriminant measure of impaired cardiac reserve in these patients.

Adult↗

PubMed1995

Evaluation of exercise capacity using submaximal exercise at a constant work rate in patients with cardiovascular disease.

BACKGROUND: Symptom-limited incremental exercise tests are used to estimate the severity of cardiovascular disease and the patient's daily activity. However, there is a need for objective parameters for submaximal exercise. To test the hypothesis that a decrease in maximal exercise capacity can be estimated by oxygen uptake (VO2) kinetics, we measured the time constant of VO2 both during the onset of constant work rate exercise at 50 W and during recovery from this exercise and compared it with data obtained during maximal exercise in patients with cardiovascular disease and in normal subjects. METHODS AND RESULTS: A total of 34 patients with cardiovascular disease and 14 normal subjects performed 6 minutes of 50-W constant work rate exercise and an incremental exercise test to the symptom-limited maximum on a cycle ergometer. VO2 was calculated from respiratory gas analysis on a breath-by-breath basis. The time constant of VO2 during the onset of 50-W exercise was 61.4 +/- 15.2 seconds in patients with cardiovascular disease, significantly longer (the kinetics of VO2 were slower) than that in normal subjects (48.8 +/- 10.4 seconds, P = .008). The time constant of VO2 during the onset of exercise was significantly negatively correlated with peak VO2 (r = -.67) and maximal work rate (r = -.66). The time constant during recovery, which did not differ significantly from that of exercise, was also prolonged in patients with cardiovascular disease; it showed a negative correlation with peak VO2 (r = -.63) and maximum work rate (r = -.54). CONCLUSIONS: The time constant of VO2 during and after recovery from 50 W of constant work rate exercise, which does not require the subject's maximal effort, is a useful and objective measure of exercise capacity in patients with mild to moderate cardiovascular disease.

Adult↗

PubMed1978

Correlation of exercise 201thallium myocardial scan with coronary arteriograms and the maximal exercise test.

Myocardial scans obtained by injecting radioactive 201thallium during exercise were correlated with electrocardiograms obtained at rest and during exercise, with coronary arteriographic abnormalities, and with left ventriculograms in 55 patients suspected of having coronary arterial disease. Thirty-nine patients had significant coronary arterial disease, 34 of whom had abnormal myocardial scans after exercise and 21 of whom had abnormal ECGs during exercise. The myocardial scan after exercise was most frequently abnormal in the presence of significant abnormalities in the Q wave or localized left ventricular asynergy and when ST-segment depression persisted for longer than ten minutes after exercise. All patients with single-vessel disease had abnormal myocardial scans after exercise, whereas five of 29 patients with two or more abnormal vessels had normal scans. Patients with coronary arterial disease were more likely to have a normal myocardial scan after exercise when the resting ECG and left ventriculogram were normal and when exercise-induced ST-segment depression persisted for less than ten minutes. The combination of the myocardial scan after exercise and the ECG during maximal exercise had a sensitivity of 98 percent. The myocardial scan after exercise alone had a specificity of 100 percent. These observations indicate that the myocardial scan obtained by injecting 201thallium during exercise is an important diagnostic adjunct in the identification of patients with coronary arterial disease.

Adult↗

PubMed1989

Exercise testing in women with chest pain. Are there additional exercise characteristics that predict true positive test results?

Women have a notoriously high rate of false positive exercise test results. Since the exercise ST segment response has low specificity in predicting CAD in women, we examined additional exercise parameters in 200 women with a history of chest pain compatible with angina and having ST segment depression greater than or equal to 1 mm recorded during a Bruce treadmill test. All subsequently had coronary arteriography. Two groups were compared: group A (n = 80) with CAD (greater than or equal to 70 percent stenosis of one or more coronary artery) and group B (n = 120) with angiographically confirmed normal coronary arteries (normal or minimal placquing). The exercise criteria analyzed included: (1) chest pain during exercise, (2) percent target heart rate, (3) extent of ST shift, (4) morphology of the ST segment slope, (5) time to normalization of the ST segment, and (6) total exercise duration. Multivariate analysis (using a stepwise logistic regression model) identified four independent exercise variables associated with the likelihood of CAD: (absence of MVP, p = .003; exercise duration less than 5 min, p = .02; ability to reach target heart rate, p = .027; time to ST normalization greater than or equal to 6 min, p less than .001). False positive exercise test results were more likely to occur when the following exercise test variables were present: ability to exercise to stage 3 of the Bruce protocol and a rapid (less than or equal to 4 minutes) normalization of ST shift after cessation of exercise. Attention to these additional exercise variables allows more careful selection of women requiring more definitive (and expensive) testing.

Angina Pectoris↗

PubMed2004

Outcomes of patients with reduced exercise capacity at time of exercise echocardiography.

OBJECTIVE: To characterize the prognostic implications of exercise echocardiography in patients who have reduced exercise capacity at the time of testing. PATIENTS AND METHODS: We examined the outcomes of 941 patients at the Mayo Clinic in Rochester, Minn, between January 1, 1990, and December 31, 1995, who had reduced exercise capacity on exercise echocardiography (women, <5 metabolic equivalents; men, <7 metabolic equivalents) and evaluated the potential association between clinical, electrocardiographic, and echocardiographic variables and outcomes for patients with normal vs abnormal exercise echocardiograms. We used variables of independent prognostic value to estimate cardiac risk. RESULTS: For patients with normal exercise echocardiograms (n=282), the rate of cardiac death or nonfatal myocardial infarction was 09% per person-year of follow-up, and previous coronary revascularization was the only predictor of the time to cardiac event. For patients with abnormal exercise echocardiograms (n=659), the cardiac event rate was 4.4%. Independent predictors of outcome were exercise left ventricular (LV) ejection fraction (risk ratio, 1.44 per 10% decrement; 95% confidence interval, 1.2-1.7; P<.001) and an increase or no change in LV end-systolic size in response to exercise (risk ratio, 2.22; 95% confidence interval, 1.2-4.1; P=.01). CONCLUSION: Exercise echocardiographic findings have important prognostic implications for patients who have reduced exercise capacity on testing. Echocardiographic descriptors of LV systolic function and dysfunction obtained immediately after exercise can be used to stratify cardiac risk of patients who do not achieve a level of exercise ordinarily considered to be of "diagnostic" value.

Aged↗

PubMed2005

Physical therapy treatment effectiveness for osteoarthritis of the knee: a randomized comparison of supervised clinical exercise and manual therapy procedures versus a home exercise program.

BACKGROUND AND PURPOSE: Manual therapy and exercise have not previously been compared with a home exercise program for patients with osteoarthritis (OA) of the knee. The purpose of this study was to compare outcomes between a home-based physical therapy program and a clinically based physical therapy program. SUBJECTS: One hundred thirty-four subjects with OA of the knee were randomly assigned to a clinic treatment group (n=66; 61% female, 39% male; mean age [+/-SD]=64+/-10 years) or a home exercise group (n=68, 71% female, 29% male; mean age [+/-SD]=62+/-9 years). METHODS: Subjects in the clinic treatment group received supervised exercise, individualized manual therapy, and a home exercise program over a 4-week period. Subjects in the home exercise group received the same home exercise program initially, reinforced at a clinic visit 2 weeks later. Measured outcomes were the distance walked in 6 minutes and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). RESULTS: Both groups showed clinically and statistically significant improvements in 6-minute walk distances and WOMAC scores at 4 weeks; improvements were still evident in both groups at 8 weeks. By 4 weeks, WOMAC scores had improved by 52% in the clinic treatment group and by 26% in the home exercise group. Average 6-minute walk distances had improved about 10% in both groups. At 1 year, both groups were substantially and about equally improved over baseline measurements. Subjects in the clinic treatment group were less likely to be taking medications for their arthritis and were more satisfied with the overall outcome of their rehabilitative treatment compared with subjects in the home exercise group. DISCUSSION AND CONCLUSION: Although both groups improved by 1 month, subjects in the clinic treatment group achieved about twice as much improvement in WOMAC scores than subjects who performed similar unsupervised exercises at home. Equivalent maintenance of improvements at 1 year was presumably due to both groups continuing the identical home exercise program. The results indicate that a home exercise program for patients with OA of the knee provides important benefit. Adding a small number of additional clinical visits for the application of manual therapy and supervised exercise adds greater symptomatic relief.

Exercise Therapy↗

PubMed1984

[Role of left ventricle angioscintigraphy during exercise in the diagnosis of coronary disease. Comparison of static and dynamic exercise].

The aim of this study was to compare the diagnostic value of exercise stress testing, Thallium 201 myocardial scintigraphy or after administration of dipyridamole and left ventricular angioscintigraphy performed either during a static (handgrip) or dynamic exercise (bicycle ergometry) for the positive diagnosis of stenosing coronary artery disease. The exercise angioscintigraphy was performed at equilibrium with 99m Tc red blood cell labelling. The global ejection fraction and that of seven radial segments of the left ventricle were measured, the data being recorded within a period of 2 minutes. The handgrip consisted in compressing a dynamometric ball at 1/3 maximal force for 3 minutes, with both hands; the ergometric exercise was increased by 30 Watt 2 minute increments until a positive ECG or 85% of the theoretical maximal heart rate for age was obtained. Normal subjects (n = 29) increased their global (+ 8%) and regional ejection fractions in each of the seven segments (p less than 0.05) during ergometric exercise: there was no significant change of global (-3% NS) or segmental ejection fractions during the handgrip exercise. In the coronary group (at least one greater than 70% stenosis) (n = 61) the fall in global ejection fraction was the same (-14%) with both forms of exercise; a similar fall in the segmental ejection fraction in the territory distal to the stenosis was observed with the handgrip (-22%) and bicycle ergometry (-28% NS). Dynamic exercise testing seemed superior to handgrip exercise. Therefore, the finding of an abnormal global ejection fraction on exercise (i.e. either a global ejection fraction less than the lower limit of normal on exercise, or lower than the global ejection fraction at rest), or of an abnormal regional ejection fraction (i.e. either a regional ejection fraction less than the lower limit of normal over at least 3 segments, or a regional ejection fraction on exercise lower than the regional ejection fraction at rest over at least 3 segments) detected coronary artery disease with a sensitivity of 94% and a specificity of 72%. Dynamic exercise angiography seemed to be more sensitive than maximal ECG stress testing (94% compared to 64%) more rapidly positive (p less than 0.05), as sensitive (94% compared to 83% NS) than Thallium myocardial scintigraphy, but less specific (72% compared to 90%, p less than 0.05), and as unspecific as ECG stress testing.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

PubMed2003

Patients with large myocardial infarction gain a greater improvement in exercise capacity after exercise training than those with small to medium infarction.

BACKGROUND: It remains unclear whether patients with large-size myocardial infarction (MI) achieve the same benefit from exercise training as do those with small- to medium-size MI. HYPOTHESIS: This study was designed to determine the magnitude and mechanisms underlying improvement in exercise capacity in patients with large-size MI after cardiac rehabilitation. METHODS: In all, 296 patients who participated in a cardiac rehabilitation program after acute MI were divided into two groups according to the peak serum creatine phosphokinase (CPK) level: the group with large infarction (Group 1) (> or = 5000 U/l peak CPK, 64 patients) and the group with less extensive infarction (Group 2) (< 5000 U/I, 232 patients). Exercise capacity was assessed before and after a 3-month cardiac rehabilitation program that included exercise training. RESULTS: Before exercise training, both the peak work rate (p < 0.05) and peak oxygen uptake (VO2) (p < 0.01) were significantly lower in Group 1 than in Group 2. After exercise training, the changes in peak work rate and peak VO2 were significantly greater in Group 1 than in Group 2 (both p < 0.01). The infarction size measured by the peak CPK level correlated significantly with both the baseline exercise capacity and its improvement after exercise training, although these correlations were insignificant in a multivariate analysis. In the multivariate analysis, the improvement in exercise capacity is determined by age and baseline exercise capacity, which is determined by the duration of inactivity, minute ventilation (VE)/VCO2 slope and left ventricular end-diastolic pressure. CONCLUSIONS: Compared with patients with small- to medium-size myocardial infarction, patients with large infarction gain a greater improvement in exercise capacity after exercise training due to reversal of physical deconditioning and improvement in congestive heart failure.

Adaptation, Physiological↗

PubMed1997

Increased urinary excretion of LTE4 after exercise and attenuation of exercise-induced bronchospasm by montelukast, a cysteinyl leukotriene receptor antagonist.

BACKGROUND: A study was undertaken to determine whether montelukast, a new potent cysteinyl leukotriene receptor antagonist, attenuates exercise-induced bronchoconstriction. The relationship between the urinary excretion of LTE4 and exercise-induced bronchoconstriction was also investigated. METHODS: Nineteen non-smoking asthmatic patients with a forced expiratory volume in one second (FEV1) of > or = 65% of the predicted value and a reproducible fall in FEV1 after exercise of at least 20% were enrolled. Subjects received placebo and montelukast 100 mg once daily in the evening or 50 mg twice daily, each for two days, in a three-period, randomised, double blind, crossover design. In the evening, approximately 20-24 hours after the once daily dose or 12 hours after the twice daily dose, a standardised exercise challenge was performed. Data from 14 patients were available for complete analysis. RESULTS: The mean (SD) maximal percentage decrease in FEV1 after exercise was 29.6 (16.0), 17.1 (8.2), and 14.0 (9.4) for placebo, once daily, and twice daily regimens, respectively. The mean (95% CI) percentage protection was 37 (15 to 59) for the group who received 50 mg twice daily and 50 (31 to 69) for those who received 100 mg once daily. Active treatments were not different from each other. The mean (SD) plasma concentrations of montelukast were higher after the twice daily regimen (1.27 (0.81) microgram/ml) than after the once daily regimen (0.12 (0.09) microgram/ml); there was no correlation between the percentage protection against exercise-induced bronchoconstriction and plasma concentrations. After exercise urinary excretion of LTE4 increased significantly during placebo treatment (from 34.3 to 73.7 pg/mg creatinine; p < 0.05) but did not correlate with the extent of exercise-induced bronchoconstriction. CONCLUSIONS: Montelukast protects similarly against exercise-induced bronchoconstriction between plasma concentrations of 0.12 and 1.27 micrograms/ml. The increase in the urinary excretion of LTE4 after exercise and the protection from exercise-induced bronchoconstriction with a cysteinyl leukotriene receptor antagonist provide further evidence of the role of leukotrienes in the pathogenesis of exercise-induced bronchoconstriction.

Acetates↗

PubMed2004

The practice and process of healthy exercise: an investigation of the treatment of exercise abuse in women with eating disorders.

This study investigates the effectiveness of an exercise program designed to reduce exercise abuse in women who are in residential treatment for eating disorders. One hundred and twenty-seven women who participated in the exercise program were compared to 127 non-participants on weight gain and self-reported obligatory attitudes and beliefs about exercise. The exercise participants were women who were medically cleared and attended at least two exercise groups during treatment. The control group were women who were medically cleared, but did not attend any exercise groups during treatment. Significant group x diagnosis interactions revealed that women in the exercise group who were diagnosed with anorexia nervosa gained more than one-third as much weight as those in the control group. Also, women in the exercise group demonstrated significantly reduced obligatory attitudes toward exercise compared to the control group. These findings suggest that the use of an exercise program that targets exercise abuse in women with eating disorders is feasible during residential treatment and results in positive change without interfering with weight gain. Limitations that result from the lack of random assignment to the exercise and control group are discussed.

Journal Article↗

PubMed2000

Post-exercise adipose tissue and skeletal muscle lipid metabolism in humans: the effects of exercise intensity.

One purpose of the present experiments was to examine whether the relative workload or the absolute work performed is the major determinant of the lipid mobilization from adipose tissue during exercise. A second purpose was to determine the co-ordination of skeletal muscle and adipose tissue lipid metabolism during a 3 h post-exercise period. Six subjects were studied twice. In one experiment, they exercised for 90 min at 40% of maximal O2 consumption (VO2,max) and in the other experiment they exercised at 60% VO2,max for 60 min. For both experiments, catheters were inserted in an artery, a subcutaneous abdominal vein and a femoral vein. Adipose tissue metabolism and skeletal muscle (leg) metabolism were measured using Fick's principle. The results show that the lipolytic rate in adipose tissue during exercise was the same in each experiment. Post-exercise, there was a very fast decrease in lipolysis, but it began to increase about 1 h post-exercise and remained elevated for the following 2 h. The increase in post-exercise non-esterified fatty acid (NEFA) mobilization was greater after 60% exercise than after 40 % exercise. It is concluded that the lipolytic rate in abdominal subcutaneous adipose tissue during exercise is the same whether the relative workload is 40% or 60% of maximum. Post-exercise, there is a substantial lipid mobilization from adipose tissue and only a small fraction of this is taken up in the lower extremities. This leaves a substantial amount of NEFAs for either NEFA/TAG (triacylglycerol) recirculation post-exercise or immediate oxidation.

Adipose Tissue↗

PubMed2003

Loss of exercise-induced cardioprotection after cessation of exercise.

Endurance exercise provides cardioprotection against ischemia-reperfusion (I/R) injury. Exercise-induced cardioprotection is associated with increases in cytoprotective proteins, including heat shock protein 72 (HSP72) and increases in antioxidant enzyme activity. On the basis of the reported half-life of these putative cardioprotective proteins, we hypothesized that exercise-induced cardioprotection against I/R injury would be lost within days after cessation of exercise. To test this, male rats (4 mo) were randomly assigned to one of five experimental groups: 1). sedentary control, 2). exercise followed by 1 day of rest, 3). exercise followed by 3 days of rest, 4). exercise followed by 9 days of rest, and 5). exercise followed by 18 days of rest. Exercise-induced increases (P < 0.05) in left ventricular catalase activity and HSP72 were evident at 1 and 3 days postexercise. However, at 9 days postexercise, myocardial HSP72 and catalase levels declined to sedentary control values. To evaluate cardioprotection during recovery from I/R, hearts were isolated, placed in working heart mode, and subjected to 20.5 min of global ischemia followed by 30 min of reperfusion. Compared with sedentary controls, exercised animals sustained less I/R injury as evidenced by maintenance of a higher (P < 0.05) percentage of preischemia cardiac work during reperfusion at 1, 3, and 9 days postexercise. The exercise-induced cardioprotection vanished by 18 days after exercise cessation. On the basis of the time course of the loss of cardioprotection and the return of HSP72 and catalase to preexercise levels, we conclude that HSP72 and catalase are not essential for exercise-induced protection during myocardial stunning. Therefore, other cytoprotective molecules are responsible for providing protection during I/R.

Animals↗