SEARCH · PubMed Health

Results for “Exercise”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 901 records · Page 50Linked to original sources

PubMed1998

The V(O2) slow component for severe exercise depends on type of exercise and is not correlated with time to fatigue.

The purpose of this study was to examine the influence of the type of exercise (running vs. cycling) on the O2 uptake V(O2) slow component. Ten triathletes performed exhaustive exercise on a treadmill and on a cycloergometer at a work rate corresponding to 90% of maximal VO2 (90% work rate maximal V(O2)). The duration of the tests before exhaustion was superimposable for both type of exercises (10 min 37 s +/- 4 min 11 s vs. 10 min 54 s +/- 4 min 47 s for running and cycling, respectively). The V(O2) slow component (difference between V(O2) at the last minute and minute 3 of exercise) was significantly lower during running compared with cycling (20.9 +/- 2 vs. 268.8 +/- 24 ml/min). Consequently, there was no relationship between the magnitude of the V(O2) slow component and the time to fatigue. Finally, because blood lactate levels at the end of the tests were similar for both running (7.2 +/- 1.9 mmol/l) and cycling (7.3 +/- 2.4 mmol/l), there was a clear dissociation between blood lactate and the V(O2) slow component during running. These data demonstrate that 1) the V(O2) slow component depends on the type of exercise in a group of triathletes and 2) the time to fatigue is independent of the magnitude of the V(O2) slow component and blood lactate concentration. It is speculated that the difference in muscular contraction regimen between running and cycling could account for the difference in the V(O2) slow component.

Adult↗

PubMed2002

VO(2) kinetics in heavy exercise is not altered by prior exercise with a different muscle group.

We examined whether lactic acidemia-induced hyperemia at the onset of high-intensity leg exercise contributed to the speeding of pulmonary O(2) uptake (VO(2)) after prior heavy exercise of the same muscle group or a different muscle group (i.e., arm). Six healthy male subjects performed two protocols that consisted of two consecutive 6-min exercise bouts separated by a 6-min baseline at 0 W: 1) both bouts of heavy (work rate: 50% of lactate threshold to maximal VO(2)) leg cycling (L1-ex to L2-ex) and 2) heavy arm cranking followed by identical heavy leg cycling bout (A1-ex to A2-ex). Blood lactate concentrations before L1-ex, L2-ex, and A2-ex averaged 1.7 +/- 0.3, 5.6 +/- 0.9, and 6.7 +/- 1.4 meq/l, respectively. An "effective" time constant (tau) of VO(2) with the use of the monoexponential model in L2-ex (tau: 36.8 +/- 4.3 s) was significantly faster than that in L1-ex (tau: 52.3 +/- 8.2 s). Warm-up arm cranking did not facilitate the VO(2) kinetics for the following A2-ex [tau: 51.7 +/- 9.7 s]. The double-exponential model revealed no significant change of primary tau (phase II) VO(2) kinetics. Instead, the speeding seen in the effective tau during L2-ex was mainly due to a reduction of the VO(2) slow component. Near-infrared spectroscopy indicated that the degree of hyperemia in working leg muscles was significantly higher at the onset of L2-ex than A2-ex. In conclusion, facilitation of VO(2) kinetics during heavy exercise preceded by an intense warm-up exercise was caused principally by a reduction in the slow component, and it appears unlikely that this could be ascribed exclusively to systemic lactic acidosis.

Acidosis, Lactic↗

PubMed2005

Exercise testing in asymptomatic adults: a statement for professionals from the American Heart Association Council on Clinical Cardiology, Subcommittee on Exercise, Cardiac Rehabilitation, and Prevention.

Along with coronary artery calcium scanning, ankle-brachial index measurement, and carotid artery ultrasound, exercise electrocardiography has been proposed as a screening tool for asymptomatic subjects thought to be at intermediate risk for developing clinical coronary disease. A wealth of data indicate that exercise testing can be used to assess and refine prognosis, particularly when emphasis is placed on nonelectrocardiographic measures such as exercise capacity, chronotropic response, heart rate recovery, and ventricular ectopy. Nevertheless, randomized trial data on the clinical value of screening exercise testing are absent; that is, it is not known whether a strategy of routine screening exercise testing in selected subjects reduces the risk for premature mortality or major cardiac morbidity. The writing group believes that a large-scale randomized trial of such a strategy should be performed.

Adult↗

PubMed1994

Exercise testing revisited. The response to exercise in normal and atopic children.

BACKGROUND: Wide differing criteria are used to define the normal airway response to exercise, and as a consequence the estimated incidence of exercise-induced bronchospasm (EIB) in atopic children is wide. The purpose of this study was to establish normal range for changes in spirometry after exercise in children and then to use these normal values to assess the incidence of EIB in atopic children. METHODS: Pulmonary function was assessed before, and 2, 5, and 10 min after 6 min of free running exercise in a group of 48 normal and 96 atopic children (70 asthmatics, 17 with allergic rhinitis, and 9 with atopic dermatitis/food hypersensitivity). RESULTS: The EIB (defined as the normal group mean value -2 SD) occurred with a > 10 percent fall in FEV1, > 17.5 percent fall in peak expiratory flow rate (PEFR), > 26 percent fall in mean forced expiratory flow during the middle half of the forced vital capacity (FEF25-75), and > 40 percent fall in FEF25. Sixty-three of 70 asthmatic patients had EIB by at least one of these definitions, most marked at 5 min postexercise. The combination of FEV1 and FEF25-75 criteria enabled detection of all subjects with EIB. By FEV1 and FEF25-75 criteria, none of the subjects with allergic rhinitis or dermatitis had EIB. The fall in FEV1 after exercise in children with allergic rhinitis was within the range of normal, but with a significantly lower mean value than control subjects. CONCLUSIONS: EIB should be defined by using more than one maximum expiratory flow-volume curve parameter (ie, FEV1 and FEF25-75). The EIB (defined as a fall in FEV1 and FEF25-75) was only seen in asthmatic children and not in other atopic groups.

Adolescent↗

PubMed1988

[Cardiac exercise tolerance of infarct patients in exercise therapy].

UNLABELLED: 92 female patients with myocardial infarction were divided into three exercise groups of 25 W, 50 W and 75 W according to their symptom-limited working capacity and examined during bicycle ergometer training. Exercise tolerance, training heart rate and arterial lactic acid were analyzed. RESULTS: 1. Increase in maximal working capacity corresponds to a decrease in limiting cardiac symptoms, or an increase of limiting symptoms, e.g., in tired leg muscles. 2. Intensity of training (as a percentage of maximal symptom-limited work capacity) is 55 +/- 21%, 73 +/- 15%, and 90 +/- 8% for groups of 25, 50 and 75 W (p less than 0.05) respectively. 3. Training heart rate and lactic acid increase significantly proportional to the increase of work capacity. 4. In all three exercise groups, training heart rate corresponds to about 84% maximal heart rate measured at maximal working capacity. 5. Mean maximal lactic acid level is at 3.18 +/- 0.97 mmol/l for the whole exercise group on 75 W. Within this group, only a small subgroup of seven women, who were limited in maximal working capacity by tired leg muscles, reached the so-called anaerobic threshold of 4 mmol/l lactic acid. 6. Female patients greater than or equal to 60 years have partially significant higher mean lactic acid levels for the same exercise load as women less than or equal to 59 years. CONCLUSION: Gender specific differences in performance in women and the cardiac situation in female patients were considered on the basis of symptom-limited performance and body-weight-related physical training, regulated by individual training heart rate.

Angina Pectoris↗

PubMed1995

Exercise prescription for sitting and supine exercise in subjects with quadriplegia.

Although in able-bodied individuals heart rate (HR) indicates exercise intensity, the linearity of the HR/oxygen uptake (VO2) relationship has not been established in persons with quadriplegia with impaired sympathetic function. The HR/VO2 relationship and four ACSM recommended methods of exercise prescription were evaluated in 11 individuals with quadriplegia during intermittent progressive peak exercise tests. Tests were conducted in either a supine or sitting position using an arm ergometer. The HR response was highly variable, with HR/VO2 correlation coefficients ranging from 0.22 to 0.99. A 2 x 2 ANOVA revealed an interaction between injury level, high-level (above C7) vs low-level (C7 and below) and exercise position, with the high-level group exhibiting the lower coefficient (0.68) between the HR/VO2 relationship in the sitting position. For all subjects, the target of 55-90% peak HR (mean = 72.5%) corresponded to 34% peak power output (PO) in sitting and 44% peak PO in supine. Similarly, 70% peak VO2 corresponded to 46% and 50% of peak PO (sitting and supine, respectively). A rating of perceived exertion (RPE) of 10-12 corresponded to 50-60% peak PO and was associated with a higher PO than that predicted by the HR or VO2 methods. The results of this study indicate that exercise intensity for quadriplegics be based on 50-60% peak PO and/or an RPE of 10-12.

Adult↗

PubMed1994

[Evaluation of the exercise capacity recovery process after lung cancer surgery by exercise test and expire gas analysis].

This study was conducted to evaluate the numerical changes and the recovery process in exercise capacity over time, and to establish new criteria that will objectively evaluate the recovery in exercise capacity after lung surgery using an expired gas analysis incorporating an exercise test. The subjects consisted of 47 patients that underwent curative resection (only lobectomy) for lung cancer in the four years from 1989 to 1992 that were able to undergo expired gas analysis incorporating an exercise test before and after surgery. The expired gas analysis were performed within one week prior to surgery and over a period from 14 to 449 days after surgery, maximum oxygen consumption (VO2max) and anaerobic threshold (AT) measured, and the VO2max/m2 and AT/m2 were calculated as an index by dividing by the body surface area (m2). In addition, in order to examine the changes in exercise capacity after surgery, the presurgical values were used as 100, and the rate of change after surgery found. These rate were divided into the following measuring times, and the postsurgical changes over time analyzed. The postsurgical measuring times were divided into five groups from 14-30 days (n = 11), from 31-90 days (n = 25), from 91-180 days (n = 8), from 181-270 days (n = 19), and greater than 271 days (n = 8) after surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1996

Blood platelet function in healthy individuals of different ages. Effects of exercise and exercise conditioning.

The influence of age, physical conditioning and physical exercise on platelet function on human being is still controversial. The aim of our study were to evaluate the effect of physical exercise on platelet activation measured by beta-thromboglobulin (beta-TG) levels and the number of platelets in sedentary and athlete subjects of different ages, and also to investigate the response of these parameters during the period of recover immediately after a bicycle exercise test. Our results show differences in platelet count and beta-TG levels among the experimental groups studied, in basal conditions, in response to the exercise test and during postexercise period. These results seem to indicate that regardless age, regular physical exercise diminish age negative effects on platelet aggregation.

Adult↗

PubMed1986

Prospective comparison of exercise digital subtraction and exercise first pass radionuclide ventriculography.

In order to test the comparative sensitivities of first-pass radionuclide and digital subtraction ventriculography in detecting wall motion abnormalities during exercise, 29 patients referred for coronary angiography were submitted to both types of stress ventriculograms. Resting and exercise ventriculograms by both techniques were reviewed by independent observers and the five equal ventricular wall segments were graded as normal, mildly, moderately, severely hypokinetic, akinetic, or dyskinetic. Of the 29 patients, 24 had arteriographically defined ischemic potential (at least greater than 50% obstruction of a major coronary artery supplying viable myocardium). Exercise digital subtraction ventriculography correctly identified 17 (71%) of these by a worsening of wall motion during exercise, while radionuclide ventriculography identified only eight (33%) by the wall motion response. When either a worsening of wall motion or the failure to increase ejection fraction by at least 5 points were used as criteria for an abnormal test, the sensitivities of digital and radionuclide ventriculographies were 96% and 79%, respectively. Though the number of patients without ischemic potential (5 patients) was too small to judge the relative specificities, digital subtraction ventriculography appears to be more sensitive than radionuclide ventriculography in identifying exercise-induced wall motion abnormalities and in predicting coronary occlusions.

Angiography↗

PubMed1987

The detection of coronary artery disease: a comparison of exercise thallium imaging and exercise equilibrium radionuclide ventriculography.

This study compared the accuracy of rest and exercise gated equilibrium technetium ventriculography with exercise thallium imaging in 50 consecutive male patients undergoing routine coronary angiography for the evaluation of chest pain. No patients were excluded on the basis of prior myocardial infarction, nature of angiographically defined coronary disease or symptoms. Antianginal therapy was continued in all patients. Eight patients had normal coronary arteries, 9 had single vessel, disease, 20 had double vessel disease and 13 had triple vessel disease. Sixteen patients had previously documented myocardial infarction. Using exercise radionuclide ventriculography, 34 patients with coronary disease were detected resulting in a sensitivity of 81%; 6 patients with normal coronary arteries had normal scans, a specificity of 75%, with a predictive accuracy of 80%. In comparison, thallium imaging detected 42 patients with coronary disease resulting in a sensitivity of 100%. Six patients with normal coronary arteries had normal thallium images resulting in a specificity of 75% and a predictive accuracy of 96%. These results suggest that exercise thallium imaging is a more accurate investigation than exercise equilibrium radio-nuclide ventriculography and is the investigation of choice in the noninvasive detection of coronary artery disease.

Adult↗

PubMed1990

Fluid replacement drinks during high intensity exercise: effects on minimizing exercise-induced disturbances in homeostasis.

The purpose of these experiments was to examine the influence of various fluid replacement drinks on exercise-induced disturbances in homeostasis during heavy exercise. Nine trained cyclists performed constant load exercise on a cycle ergometer to fatigue on three occasions with 1-week separating experiments. The work rate was set initially at approximately 85% of VO2max (range 82-88%) with fatigue being defined as a 10% decline in power output below the initial value. During each experiment subjects consumed one of the following three beverages prior to and every 15 min during exercise: (1) non-electrolyte placebo (NEP; 31 mosmol.kg-1); (2) glucose polymer drink containing electrolytes (GP; 7% CHO, 231 mosmol.kg-1), and (3) electrolyte placebo drink without carbohydrate (EP; 48 mosmol.kg-1). Both the GP and EP beverage contained sodium citrate/citric acid (C) as a flavoring agent while C was not contained in the NEP drink. Although seven of nine subjects worked longer during the GP and EP treatment when compared with the NEP trial, the difference was not significant (P greater than 0.05). No differences (P greater than 0.05) existed between the GP and EP treatments in performance time. Exercise changes in rectal temperature, heart rate, delta % plasma volume and plasma concentrations of total protein, free fatty acids, glucose, lactate, potassium, chloride, calcium, and sodium did not differ (P greater than 0.05) between trials.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1995

Pre-exercise serum cortisol concentration and responses to laboratory exercise.

Relationships between the postexercise values of blood lactate concentration, pH, oxygen uptake, heart rate, power output on the one hand, and the pre- and postexercise blood cortisol concentrations on the other, were studied in 74 male and 40 female athletes (wrestlers and senior and junior rowers), performing graded exercise of increasing intensity. The senior rowers, junior rowers and wrestlers had different exercise protocols. The senior rowers of both sexes had significantly higher rest concentrations of serum cortisol than the junior athletes. A significant correlation between postexercise lactate concentrations and pre-exercise cortisol concentrations was found in all the male groups ("common" r = 0.515, P < 0.001), but not in the female ones (r = 0.162). It was concluded that the pre-exercise cortisol concentrations might condition anaerobic-glycolytic metabolism in physical exercise.

Adolescent↗

PubMed1992

The causes and clinical significance of exercise-induced silent myocardial ischemia evaluated by ischemic range and intensity with exercise Tl-201 myocardial SPECT.

We investigated the causes and long-term prognosis of exercise-induced silent myocardial ischemia (SMI) by means of exercise Tl-201 myocardial SPECT (Ex-SPECT) in 97 patients with effort angina or old myocardial infarction (OMI). These patients were proven to have significant stenosis by coronary angiography. The subjects were divided into three groups based on the presence or absence of Tl-201 redistribution or angina during exercise testing. Group one consisted of 34 patients who had redistribution on Ex-SPECT and angina during exercise testing: the painful myocardial ischemia (PMI) group. The second group consisted of 38 patients who had redistribution on Ex-SPECT, but no angina during exercise testing: the SMI group. The third group consisted of 25 patients who had no redistribution: the RD (-) group. The ischemic range and intensity were quantified by the defect volume ratio (DVR) and defect severity index (DSI), respectively. Comparison of the DVR and DSI values for the PMI and SMI groups revealed that the DVR and DSI values for the SMI group were lower than those of the PMI group. Also the prognosis of the SMI group tended to be worse than that of the RD (-) group. Thus, we concluded that the SMI and PMI group should receive identical treatment.

Aged↗

PubMed1985

Acute response to submaximal and maximal exercise consequent to beta-adrenergic blockade: implications for the prescription of exercise.

Forty-seven healthy male subjects, 17 to 34 years old, completed a test to exhaustion on a motor-driven treadmill to determine their maximal oxygen uptake. A second test was administered 2 days later during which the subject walked for 20 to 25 minutes at a steady-state level representing 60% of the maximal oxygen uptake as determined in the first test. The grade was then increased every 2 minutes until the subject reached the state of exhaustion. After the second test, the subjects were randomly assigned, in a double-blind manner, to either placebo, propranolol (160 mg/day), or atenolol (100 mg/day) treatment for 7 days. Exactly 1 week from the time of the second test, and 3 hours after the last medication, the subjects completed the final exercise test using the same treadmill protocol administered in the second test. Heart rate and systolic blood pressure at rest and during submaximal steady-state exercise were significantly reduced by both drugs, whereas diastolic pressure was unaffected. During submaximal steady-state exercise, cardiac output was reduced in both the placebo and atenolol groups, stroke volume was increased in both atenolol and propranolol groups, oxygen uptake was reduced in the atenolol group, pulmonary ventilation was reduced in both propranolol and atenolol groups, and the respiratory exchange ratio remained unchanged. With maximal exercise, treadmill time was significantly reduced with propranolol, pulmonary ventilation and heart rate were reduced significantly with both drugs, but maximal oxygen uptake remained unchanged. Thus, beta blockade does not appear to limit ability to exercise. However, there appears to be a significant advantage to using a cardioselective rather than a nonselective beta-blocking agent.

Adolescent↗

PubMed1986

Risk factors, exercise fitness and electrocardiographic response to exercise in 12,866 men at high risk of symptomatic coronary heart disease.

The association between coronary heart disease (CAD) risk factors with submaximal exercise performance was examined among 12,866 men at high risk in the Multiple Risk Factor Intervention Trial (MRFIT). Men were selected from a risk score based on serum cholesterol level, diastolic blood pressure and number of cigarettes smoked per day. Multivariate analysis using exercise ST depression as the dependent variable showed age, diastolic blood pressure and serum cholesterol level were significant positive predictors of ST depression and cigarettes per day, body mass index and heart rate at rest were significant negative predictors of ST depression. Similarly, multivariate analysis, using exercise duration as the dependent variable, revealed that age, cholesterol level, body mass index and heart rate at rest were significant negative predictors of exercise duration, whereas cigarettes per day and leisure-time physical activity were significant positive predictors. Some of these relationships with exercise performance are consistent with established epidemiologic CAD risk factor associations and others are not. The MRFIT selection process, which resulted in smokers who were significantly younger and who had significantly lower levels of other CAD risk factors than nonsmokers, was partially responsible.

Adult↗

PubMed1989

Exercise thallium-201 scintigraphy and prognosis in typical angina pectoris and negative exercise electrocardiography.

Patients with a history of typical angina but negative exercise electrocardiography represent a subgroup with an intermediate likelihood of having coronary artery disease and future cardiac events. A retrospective study of the prognostic utility of stress-redistribution thallium-201 scintigraphy was performed in 190 such patients. A second group of 203 patients with typical angina and a positive exercise electrocardiogram were analyzed for comparative scintigraphic purposes. The cardiac event rate for the 144 negative exercise electrocardiogram patients with normal thallium results was 5 vs 15% in the 46 patients with abnormal thallium results (p = 0.01). These patients were further stratified into high (14 to 18%), intermediate (9%) and low (less than 2%) risk groups for future cardiac events based on combining the thallium results with the percentage of maximal predicted heart rate achieved. A multivariate analysis revealed that an abnormal thallium result was the only significant correlate of future cardiac events. Mechanisms responsible for the discordant finding of a negative exercise electrocardiogram in patients with typical angina include (1) false-positive angina symptomatology in low prevalence coronary artery disease groups in whom the thallium test is negative, and (2) "electrocardiographically silent" ischemia in patients in whom the thallium test is positive. These findings reveal that thallium stress-redistribution scintigraphy can be used to stratify 1-year prognosis in this subgroup of patients with typical angina and negative exercise electrocardiograms.

Angina Pectoris↗

PubMed1991

Usefulness of ambulatory silent myocardial ischemia added to the prognostic value of exercise test parameters in predicting risk of cardiac death in patients with stable angina pectoris and exercise-induced myocardial ischemia.

The prognostic significance of ambulatory silent ischemia detected by Holter monitoring during daily life was prospectively evaluated and compared with several exercise test parameters in 86 patients with stable angina and positive exercise tests. Forty-seven patients (group 1) had no evidence of ischemia and 39 (group 2) had 1 or more episodes of silent ischemia during the monitoring period. During mean follow-up of 24 +/- 8 months there were only 2 cardiac deaths (nonsudden) in group 1 (4% mortality) compared with 9 (3 sudden and 6 nonsudden) in group 2 (23% mortality). Kaplan-Meier actuarial analysis revealed worse survival (p less than 0.008) for patients in group 2. The Cox regression analysis of clinical variables, electrocardiographic and exercise parameters, angiographic data and Holter monitoring results revealed silent ischemia during daily life as the most powerful predictor of cardiac mortality (p = 0.003). These results demonstrate that in patients with chronic stable angina and abnormal exercise tests, ambulatory ischemia detected by Holter monitoring provides significant additional prognostic information to that derived from evaluation of exercise test parameters alone.

Actuarial Analysis↗

PubMed1995

Stress responsivity in exercisers and non-exercisers during different phases of the menstrual cycle.

It has been suggested that, premenstrually, women are more vulnerable to the effects of stress. It has also been proposed that the fitter the individual is, the less the body responds to, and the more quickly it recovers from, a stressful experience. The present study investigated whether premenstrual sensitivity to a stressful laboratory task would be attenuated in women who exercised. Responses to the task across the menstrual cycle were studied in 20 women who exercised regularly and 20 women who were sedentary. Heart rate and blood pressure as well as subjective mood responses were measured in each of three phases: premenstrual, menstrual and postmenstrual. Exercising and sedentary women differed in sensitivity to stress: heart rate responsivity to stress was less in exercisers, but mood fluctuation was greater. Menstrual cycle phase, by contrast, influenced general levels of heart-rate and mood, but did not affect responsivity to stress or performance. These findings suggest that the menstrual cycle and physical exercise have independent effects on cardiovascular and emotional state.

Adaptation, Psychological↗