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PubMed1995

Exercise pad testing in continent exercisers: reproducibility and correlation with voided volume, pyridium staining, and type of exercise.

This study was undertaken to determine normal values for a modified pad test to be used for testing outcomes of studies addressing therapy for exercise incontinence. Fourteen asymptomatic volunteers who were continent by history completed three similar exercise sessions wearing pre-weighed pads after ingesting phenazopyridine hydrochloride (Pyridium, Parke-Davis, Sandy, UT). The mean pad weight gain for all exercise sessions combined was 3.19 +/- 3.16 g (range 0.1-12.4). The mean area of pyridium staining was 2.66 +/- 3.14 mm. Mean volume voided after the exercise sessions was 193 +/- 108 cc (range 10-625). The Kendall coefficient of concordance used to test the interest reliability was 0.96 for pad weight gain, 0.76 for area of stain, and 0.60 for volume voided. All but one of the subjects had at least one spot of pyridium stain on at least one of the three pads. The increase in pad weight attributable to sweat and vaginal moisture is reproducible in a given individual performing the same exercise routine, but due to the large variation between subjects, we were unable to establish a cut-off value separating continence from incontinence. Adding pyridium did not improve the specificity of the test, despite instructing subjects to milk the urethra and blot before applying the pad.

Adult↗

PubMed1984

Exercise-induced pulmonary hemorrhage in exercising Thoroughbreds: preliminary results with pre-exercise medication.

Thoroughbreds with a confirmed history of exercise-induced pulmonary hemorrhage (EIPH) were treated pre-exercise with atropine sulfate, cromolyn, ipratropium or furosemide. Atropine prevented EIPH in 3 of 3 trials in 1 horse, while having no significant effect on bleeding status in the other 2 horses. Pre-exercise treatment with cromolyn had no significant effects in the 3 horses. Pre-exercise treatment of ipratropium was apparently responsible for preventing EIPH in 17 out of 18 trials in 2 horses. The pharmacologic properties of ipratropium in the horse have not been studied, but based on human investigation it seems most probable that its bronchodilator effects are responsible for preventing EIPH in the 2 horses. Furosemide administered in different dosages and time intervals prior to exercise did not prevent EIPH in these 3 horses.

Animals↗

PubMed1999

Effects of pre-exercise frusemide administration and post exercise anaesthesia on cardiopulmonary and acid-base parameters and blood and plasma volumes in horses exercised supramaximally to fatigue.

Six horses were randomly assigned to receive either frusemide (F) (0.5 mg/kg i.v.) or an equivalent volume of saline (S) i.v., 4 h prior to treadmill exercise. Horses were instrumented to enable measurement of heart rate (HR), systolic (SAP), mean (MAP), and diastolic (DAP) carotid arterial pressures, pulmonary artery pressure (PAP), central venous pressure (CVP), pulmonary arterial temperature (TEMP), blood gases, and cardiac output (CO). Plasma (PV) and blood volumes (BV) were measured using 2 injections of Evan's Blue dye. Baseline parameters were recorded while the horse stood quietly. Horses were then administered F or S. Four hours later, they were warmed up for 3 min at 4 m/s and then exercised to the point of fatigue at 115% VO2max. Horses were anaesthetised immediately following exercise by administration of detomidine (0.04 mg/kg bwt i.v.) followed 5 min later by tiletamine-zolazepam (1.25 mg/kg bwt i.v.). After transporting the horse to a recovery stall, anaesthesia was maintained with isoflurane in 100% O2. Data were analysed using a 2-way ANOVA with repeated measures with post hoc differences identified using the Student-Newman-Keul's procedure. Exercise was associated with increases in HR, SAP, MAP, DAP, PAP, CVP, TEMP, PCV, and BV, and decreases in PV, pH, arterial bicarbonate and base excess. Anaesthesia was associated with marked hypercapnia, a decrease in HR following detomidine administration, and persistent pulmonary hypertension despite carotid arterial pressure which returned to baseline. No effects attributable to F were identified at any time during the study.

Acid-Base Equilibrium↗

PubMed1995

Additional weight-bearing during exercise is more important than duration of exercise for anabolic stimulus of bone: a study of running exercise in female rats.

Mechanical loading is necessary for maintenance of skeletal integrity, but the most effective type, intensity, and duration of exercise are not known. In vivo experiments have indicated that the strain generated by the stimulus is more important than the duration of the stimulus. To elucidate this question, we studied 5-month-old female Wistar rats exercised on a motor-driven exercise belt for 17 weeks, 5 days per week (average velocity 20 m/min). Group 1 served as controls, group 2 was trained for 30 min, group 3 was trained for 30 min with a 50-g backpack, and group 4 was trained for 15 min with a 50-g backpack. Total body bone mineral content (BMC), bone mass of the lower extremities (LEBMC), total body lean soft-tissue mass (LSTM), and total body fat-tissue mass (FTM) were measured by dual-energy absorptiometry (DXA) at 0, 6, and 17 weeks. The BMC increased more in group 4 than in controls (15% vs. 8%, p < 0.03). In the other two intervention groups, no significant increases of total body BMC occurred compared with controls, although a trend was observed (12%). The LEBMC increased significantly in all exercising groups after 17 weeks, being 16% in group 2, 15% in group 3, and 20% in group 4, compared with 6% in controls (p < 0.05). The increase in LSTM after 6 weeks was most pronounced in group 3, at 20%, compared with 10% in the control group (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗

PubMed1986

Functional translation of exercise responses from graded exercise testing to exercise training.

This study attempts to develop a quantitative approach to the prescription of absolute exercise intensity during level ground ambulation (min/mile) or cycle ergometry (kpm) from responses observed during GXT. A total of 345 subjects performed GXT and exercise training sessions with either the Bruce treadmill protocol and level ground ambulation (N = 154) or cycle ergometry (N = 191). Responses from 90% of each group were used to generate equations for predicting training pace (or power output) from the time (or power output) during the GXT when target HR was achieved. FAI was also included in the prediction of training pace (or power output). The remaining 10% of subjects in each group were used to cross-validate the prediction equations. The correlation between the time (or power output) during GXT when the training HR was observed and the pace of ambulation (or power output) was 0.70 for treadmill walking and 0.88 for cycle-cycle. Correlations were increased by the addition of FAI to the prediction equation. The results of this investigation suggest that the absolute intensity of exercise for training can be predicted accurately from GXT results.

Cardiac Rehabilitation↗

PubMed2001

Aerobic exercise interventions for people with HIV/AIDS.

BACKGROUND: The profile of HIV infection is constantly changing. Although once viewed as an illness progressing to death, HIV infection now presents as a chronic infection characterized by unpredictable cycles of wellness and illness. Thus, the needs of this population have increasingly included management of impairments, disabilities and handicaps. Exercise is a key management strategy employed by rehabilitation professionals to address these issues. Exercise has been shown to improve strength, cardiovascular function, and psychological status in seronegative populations (see Eds., Bouchard, C., Shephard, R.J., & Stephens, T. (1993). Physical Activity, Fitness, and Health. Champaign, IL: Human Kinetics Publishers.) But what are the effects of exercise for people living with HIV infection? If the risks and benefits of exercise for people living with HIV infection are better understood, appropriate exercise prescription may be practiced by health care providers. Improved exercise prescription may enhance the effectiveness of HIV management, thus improving overall outcomes for people living with HIV infection. OBJECTIVES: To examine the effect of aerobic exercise interventions on cardiopulmonary, immunologic and psychological parameters in adults living with HIV infection. SEARCH STRATEGY: Studies were identified using MEDLINE, EMBASE, SCIENCE CITATION INDEX, AIDSLINE CINAHL, HEALTHSTAR, PSYCHLIT, SOCIOFILE, SCI, SSCI, ERIC, DIA and abstracts from international AIDS meetings, ICAAC, and other major meetings. Reference lists from pertinent articles and books and personal contact with authors were also used, as were Collaborative Review Group databases and results of hand searching of targeted journals. All languages were included. Searches covered the period from 1980 to July 1999. SELECTION CRITERIA: For inclusion, studies had to be randomized control trials involving HIV+ adults 18 years of age or older and had to include at least one group randomized to receive aerobic exercise performed at least three times/week for at least four weeks. DATA COLLECTION AND ANALYSIS: Data on study design, participants, interventions, and outcomes were extracted from the reports onto specifically designed data collection forms by at least two reviewers. MAIN RESULTS: Six studies satisfied the eligibility criteria. The main results indicated that performing constant or interval aerobic exercise for at least 20 minutes, at least three times per week for four weeks may lead to increased CD4 count, improved cardiopulmonary fitness, and improved psychological status. These findings are limited to those who continued to exercise and for whom there was adequate follow-up data. REVIEWER'S CONCLUSIONS: Aerobic exercise appears to be safe and may be beneficial for adults living with HIV/AIDS. These findings are limited by the small sample sizes and large drop-out rates of the included studies. Further research is required to determine the optimal parameters of aerobic exercise and stage of disease in which aerobic exercise may be most beneficial for adults living with HIV infection.

CD4 Lymphocyte Count↗

PubMed1991

Effect of exercise intensity and duration on regional function during and after exercise-induced ischemia.

BACKGROUND: Transient reversible myocardial dysfunction has been documented after episodes of exercise-induced ischemia. This study was undertaken to determine whether the duration or intensity of exercise affects the severity of postischemic dysfunction in this setting. METHODS AND RESULTS: Ten dogs were instrumented with ultrasonic microcrystals for measurement of wall thickening, with circumflex coronary artery flow probes, and with hydraulic occluders. Dogs performed low-intensity exercise, which was sufficient to increase coronary perfusion 50% above control, and high-intensity exercise, which was sufficient to double coronary blood flow. To investigate the effects of exercise intensity on postischemic dysfunction, we had dogs perform high-intensity exercise for 5 minutes in the presence of a stenosis. On the alternate day, dogs performed low-intensity exercise for 10 minutes in the presence of a stenosis. These two protocols provide equivalent coronary flow debts. Mean transmural blood flow during high-intensity exercise without stenosis (2.61 +/- 0.54 ml/min/g) was significantly higher than that during low-intensity exercise (1.74 +/- 0.61 ml/min/g, p less than 0.002). During high-intensity exercise with coronary artery stenosis, subendocardial blood flow was significantly lower than that during low-intensity exercise with stenosis (0.64 +/- 0.40 versus 1.08 +/- 0.28 ml/min/g, p less than 0.02). This difference in subendocardial perfusion was associated with greater degrees of regional dysfunction during exercise (circumflex wall thickening was 44 +/- 23% of control for high-intensity exercise versus 60 +/- 18% of control for low-intensity exercise, p less than 0.01). In addition, from 10 to 30 minutes after exercise, wall thickening in myocardium perfused by the circumflex coronary artery remained significantly lower after high-intensity exercise than that after low-intensity exercise. To assess the effects of exercise duration on the severity of postischemic dysfunction, we had dogs perform low-intensity exercise in the presence of a coronary stenosis for 10 minutes and low-intensity exercise for only 5 minutes on alternate days. Systolic wall thickening was significantly lower after low-intensity exercise for 10 minutes than after low-intensity exercise for 5 minutes. CONCLUSIONS: High-intensity exercise results in greater degrees of subendocardial hypoperfusion and greater degrees of regional dysfunction both during and after exercise-induced ischemia than does low-intensity exercise. Second, exercise duration also exerts an effect on the severity of postischemic dysfunction, although the magnitude of this effect is less important than the effect of exercise intensity.

Animals↗

PubMed2002

Exercise-induced hypoalgesia and intensity of exercise.

Pain sensitivity has been found to be altered following exercise. A number of investigators have found diminished sensitivity to pain (hypoalgesia) during and following exercise. However, currently it is unknown whether there is a specific intensity of exercise that is required to produce this hypoalgesia response. Aerobic exercise, such as cycling and running, have been studied most often, and a number of different exercise protocols have been used in this research including: (i) increasing exercise intensity by progressively increasing the workloads; (ii) prescribing a particular exercise intensity based on a percentage of maximum; and (iii) having participants self-select the exercise intensity. Results indicate that hypoalgesia occurred consistently following high-intensity exercise. In the studies in which exercise intensity was increased by increasing workloads, hypoalgesia was found most consistently with a workload of 200 W and above. Hypoalgesia was also found following exercise prescribed at a percentage of maximal oxygen uptake (e.g. 60 to 75%). Results are less consistent for studies that prescribed exercise based on percentage of heart rate maximum, as well as for studies that let participants self-select the exercise intensity. However, there has not been a systematic manipulation of exercise intensity in most of the studies conducted in this area. In addition, the interaction between exercise intensity and exercise duration, more than likely influences whether hypoalgesia occurs following exercise. There is a need for research to be conducted in which both intensity and duration of exercise are manipulated in a systematic manner to determine the 'optimal dose' of exercise that is required to produce hypoalgesia. In addition, there is a need for more research with other modes of exercise (e.g. resistance exercise, isometric exercise) to determine the optimal dose of exercise required to produce hypoalgesia.

Exercise↗

PubMed2000

Nedocromil sodium for preventing exercise-induced bronchoconstriction.

BACKGROUND: Exercise-induced asthma causes cough, dyspnea, wheeze and chest tightness. Management of focuses on prevention through pharmaco-therapy and alternate strategies. Single use, pre-exercise beta2-agonists and non-steroidal anti-inflammatory agents such as the cromones are the most common treatments. OBJECTIVES: The objective of this review was to assess the effects of a single dose of nedocromil sodium to prevent exercise-induced bronchoconstriction. SEARCH STRATEGY: We searched the Cochrane Airways Group trials register, the Cochrane Controlled Trials Register, Current Contents, review articles, textbooks and reference lists of articles. We also contacted the drug manufacturer and primary authors for additional citations. SELECTION CRITERIA: Randomised trials comparing a single dose of nedocromil sodium with placebo to prevent exercise-induced bronchoconstriction in people over six years of age. DATA COLLECTION AND ANALYSIS: Trial quality assessment and data extraction were conducted independently by two reviewers. Study authors were contacted for confirmation of data. MAIN RESULTS: Twenty randomised controlled trials involving 280 participants were identified. 15-60 min following inhalation of 4 mg nedocromil, the maximum fall in forced expiratory volume in one second due to exercise was improved by 15.6%, (95% CI:13.2 to 18.1) compared to the placebo response. The maximum percentage fall in peak expiratory flow rate was of the same magnitude (weighted mean difference 15.0%; 95% CI 8.3 to 21.6). Nedocromil shortened the time to recover lung normal function from more than 30 minutes with placebo to less than 10 minutes with the drug. The relative magnitude of its effect was greatest in patients with more severe exercise-induced bronchoconstriction (defined as an exercise-induced fall in lung function > 30% from baseline). There were no significant adverse effects reported. REVIEWER'S CONCLUSIONS: Nedocromil sodium used before exercise appears to reduce the severity and duration of exercise-induced bronchoconstriction. This effect appears to be more pronounced in people with severe exercise-induced bronchoconstriction.

Adolescent↗

PubMed1981

Value of exercise thallium-201 imaging in patients with diagnostic and nondiagnostic exercise electrocardiograms.

The role of exercise imaging with thallium-201 in the evaluation of patients suspected of having coronary artery disease was studied in 194 patients undergoing diagnostic coronary arteriography. Ninety-eight patients had 70 percent or more narrowing of one or more coronary vessels and 96 patients had either no or insignificant coronary artery disease. One hundren twenty-three of the 194 patients had conclusive treadmill exercise electrocardiograms (either positive or negative), and 71 had inconclusive exercise electrocardiograms. Fifty-four of the 98 patients with coronary artery disease were receiving propranolol at the time of testing. Forty-five (83 percent) of the 54 patients receiving propranolol and 33 (75 percent) of the 44 patients not receiving propranolol had abnormal exercise thallium images (difference not significant). In patients with conclusive exercise electrocardiograms the sensitivity of exercise imaging was not significantly different from that of exercise electrocardiograms (80 versus 74 percent), but the sensitivity of both tests combined (92 percent) was higher than that of either test alone (p less than 0.01). The specificity of exercise imaging (97 percent) electrocardiograms the sensitivity of exercise imaging was not significantly different from that of exercise electrocardiograms (80 versus 74 percent), but the sensitivity of both tests combined (92 percent) was higher than that of either test alone (p less than 0.01). The specificity of exercise imaging (97 percent) electrocardiograms the sensitivity of exercise imaging was not significantly different from that of exercise electrocardiograms (80 versus 74 percent), but the sensitivity of both tests combined (92 percent) was higher than that of either test alone (p less than 0.01). The specificity of exercise imaging (97 percent) was higher than that of exercise electrocardiograms (86 percent, p less than 0.02). The specificity of both tests combined was not significantly different from that of exercise electrocardiograms alone. The sensitivity (79 percent) and specificity (95 percent) of exercise imaging were not significantly different in patients with inconclusive exercise electrocardiograms when compared with those in patients whose exercise electrocardiograms were conclusive. These data indicate that exercise imaging is sensitive and specific in diagnosing coronary artery disease in the presence of diagnostic as well as nondiagnostic exercise electrocardiograms and that propranolol therapy does not affect the results.

Angina Pectoris↗

PubMed2003

Accuracy of peak treadmill exercise echocardiography to detect multivessel coronary artery disease: comparison with post-exercise echocardiography.

AIMS: Although peak exercise echocardiography has been reported for both bicycle and treadmill exercise and has shown higher sensitivity than post-exercise imaging, little is known about its utility for identifying multivessel involvement. We sought to compare feasibility and accuracy of peak treadmill exercise echocardiography vs post-exercise echocardiography for identification of multivessel coronary artery disease and to assess its incremental value when combined with clinical and exercise test variables. METHODS AND RESULTS: The study group included 335 patients (228 men; mean (+/- SD) age 60 +/- 11 years). Two hundred and seventy-nine patients were included on the basis of having had an exercise echocardiography and a coronary angiography within 4 months of the exercise test. To avoid bias to coronary angiography, a subgroup of 56 consecutive non-diabetic patients referred for exercise echocardiography with pretest probability of coronary artery disease <10% and had atypical chest pain or were asymptomatic were also included and considered as having no coronary artery disease. Multivessel coronary artery disease (> or = 50% diameter stenosis in >1 vessel) was confirmed in 170 patients, whereas 165 patients were considered to have one-vessel coronary artery disease or no coronary lesions. Positive exercise echocardiography was defined as ischaemia or necrosis in at least two coronary territories. Post-exercise images were acquired within 125 s after exercise (49 +/- 15). Mean heart rate (bpm) was 139 +/- 19 at peak vs 117 +/- 22 at post-exercise imaging (P<0.001). Interpretable peak and post-exercise images were obtained for all patients. Sensitivity for predicting multivessel disease was higher with peak than with post-exercise imaging (79 vs 55%, P<0.001), with lower specificity (79 vs 88%, P<0.05). Predictive positive value was similar (80 vs 83%). Negative predictive value was again higher with peak imaging (78 vs 66%, P<0.01). Total accuracy was not different (79 vs 72%). A stepwise logistic regression analysis identified peak exercise echocardiography positivity for multivessel coronary artery disease as the strongest independent predictor of multivessel disease (odds ratio (OR): 7.36); also significant were male gender (OR: 4.22), diabetes mellitus (OR: 4.28), previous myocardial infarction (OR: 3.12) and increment of product heart rate x blood pressure (OR: 1.00). CONCLUSIONS: Peak treadmill exercise echocardiography is technically feasible and has higher sensitivity and negative predictive value for predicting multivessel disease than post-treadmill exercise echocardiography. This method adds independent and incremental values to clinical and exercise variables for the diagnosis of multivessel coronary artery disease. Therefore, in the clinical setting, peak exercise echocardiography should be performed to diagnose multivessel coronary artery disease.

Aged↗

PubMed1997

Post-exercise cutaneous hyperaemia resulting from local exercise of an extremity.

Large changes in skin blood flow occur after exercise. Most studies have concentrated on the systemic effects of vigorous exercise on skin blood flow. We were interested in the post-exercise response in the neighbourhood of focal exercise. We used a painless neuromuscular electronic stimulator to exercise the muscles of the forearm, producing flexion of the fingers. There was no change in blood pressure and only a small increase in heart rate during this exercise. We measured blood flow during a 5-min pre-exercise period and a 5-min post-exercise period at the forearm, at the dorsum of the index finger and on the pad of the index finger. We also measured values on the contralateral non-exercised extremity during exercise as well as during matched time periods in control experiments with no exercise. Exercise did elicit an increased blood flow in the post-exercise period at all three sites compared with the control experiments with no exercise and on the contralateral extremity. For example, the increase in blood flow at the finger dorsum was 2.1 +/- 0.1 ml (min 100 g)-1 after exercise compared with -0.08 +/- 0.09 ml min-1 100 g-1 during the control experiment and 0.1 +/- 0.1 ml (min 100 g)-1 on the contralateral arm (all P < 0.01). The local application of heat at the site of blood flow monitoring produced a substantial increase in the post-exercise response at the two finger locations [27.4 +/- 0.4 ml (min 100 g)-1 at the finger dorsum], but not at the arm. This is the first demonstration that highly focal exercise, unaccompanied by a systemic haemodynamic response, can elicit a post-exercise cutaneous hyperaemia. Local heating produced a large synergistic increase in the post-exercise hyperaemia at sites with arteriovenous microvascular perfusion but not at sites with primarily nutritive perfusion. These findings show that local vasoregulatory changes occur in response to exercise, even in the absence of whole-body haemodynamic and thermal change.

Arm↗

PubMed2000

An office-based instrument for exercise counseling and prescription in primary care. The Step Test Exercise Prescription (STEP).

BACKGROUND: Available evidence suggests that despite physicians' positive attitudes toward exercise as an important part of promoting a healthy lifestyle, few physicians actually prescribe exercise for their patients. One barrier may be lack of a standard office instrument. OBJECTIVES: To determine the (1) exercise counseling habits among a large group of Canadian family physicians and (2) acceptance and utilization of an exercise counseling instrument geared to primary care practice. DESIGN: Randomized control trial. SETTING: Primary care practice. PARTICIPANTS: Family physicians (N = 400) from 3 regions of Canada, representing both rural and urban practice (ratio of 1:3). Patients (10 per practice) were healthy community dwellers older than 65 years obtained as a convenience sample in their family practice. INTERVENTIONS: In phase 1, 400 physicians listed as being in general or family practice by their provincial registries were randomly selected from a larger group listed by these registries and contacted by telephone. A total of 362 completed a 10-minute questionnaire that detailed practice demographics, preventive practice, and exercise counseling habits. In phase 2, 293 agreed to further participate in the administration of an exercise prescription randomly assigned to them by the study team. Two methods of exercise prescription were compared: counseling using the American College of Sports Medicine guidelines (control) and counseling using guidelines and an office-based step test (Step Test Exercise Prescription [STEP]) to determine fitness level and prescribe an exercise training heart rate. Physicians were asked to deliver their assigned exercise prescription to a convenience sample of the next 10 healthy patients older than 65 years who presented to the office. MAIN OUTCOME MEASURES: Primary outcome measures were physician exercise counseling confidence and knowledge before and after the study. Secondary outcomes included details of the exercise counseling sessions (e.g., time required). RESULTS: In phase 1, more than 90% of the 362 physicians claimed to practice preventive health counseling, and 70% claimed to include exercise counseling. Only 67.4% felt confident regarding their exercise prescribing, and most (93.8%) were interested in improving their exercise prescribing skills. The leading barriers to exercise prescription were described in order as inadequate time, lack of necessary skills and tools, and lack of reimbursement. In phase 2, no difference in physician profile, patient profile, or indications for exercise counseling were observed between control (n = 145) and STEP (n = 148) groups. STEP was significantly longer (16.4 vs 12.9 min; P = .001) to administer; however, improvement in physician confidence (P = .01) and knowledge (P = .009) were significantly greater compared with controls. CONCLUSIONS: Most family physicians practiced preventive exercise counseling but reported lack of time and skills as barriers to this practice. Physicians randomized to the STEP group took longer to deliver exercise advice but felt more confident and knowledgeable compared with controls.

Aged↗

PubMed2000

Exercise-based rehabilitation for coronary heart disease.

BACKGROUND: The burden of cardiovascular disease world-wide is one of great concern to patients and health care agencies alike. Circulatory diseases, including myocardial infarction (MI) and stroke, kill more people than any other disease. Cardiac rehabilitation aims to restore patients who have suffered myocardial infarction to optimal health through exercise only based rehabilitation or comprehensive cardiac rehabilitation (eg. smoking cessation advice, diet and counselling as well as exercise). Data from two published and widely cited meta-analyses (Oldridge 1988, O'Connor 1989) of over 4,000 patients each have demonstrated that patients randomised to exercise-based cardiac rehabilitation after MI have a statistically significant reduction in all-cause and cardiac mortality of about 20 to 25% compared to patients receiving conventional care. However, the trials included were small and often of poor methodological quality. Incomplete literature review methods may have resulted in publication bias thereby resulting in an over-estimate of the benefit of cardiac rehabilitation. The randomised controlled trials used in the reviews have focused almost exclusively on low-risk, middle-aged males post MI, thereby excluding women and the elderly. OBJECTIVES: To determine the effectiveness of exercise only rehabilitation and exercise in addition to other rehabilitation interventions (termed comprehensive cardiac rehabilitation) compared with usual care on the mortality, morbidity, health-related quality of life (HRQoL) and modifiable cardiac risk factors of patients with coronary heart disease. SEARCH STRATEGY: Electronic databases were searched for randomised controlled trials, using standardised trial filters, from the earliest date available to December 31st 1998. SELECTION CRITERIA: Men and women of all ages, in both hospital-based and community-based settings, who have had myocardial infarction, coronary artery bypass graft or percutaneous transluminal coronary angioplasty, or who have angina pectoris or coronary artery disease defined by angiography have been included. Studies involving participants following heart transplant, heart valve surgery or heart failure have been excluded. Follow up periods of less than 6 months were excluded. DATA COLLECTION AND ANALYSIS: Studies were selected independently by two reviewers, and data extracted independently. Authors were contacted where possible to obtain missing information. MAIN RESULTS: The current systematic review has allowed analysis of an increased number of patients from approximately 4500 in the earlier meta-analyses to 7683 (2582 in exercise only and 5101 in the comprehensive cardiac rehabilitation group). The quality of reporting overall was poor, with generally high losses to follow up. The pooled effect estimate for total mortality for the exercise only intervention shows a 27% reduction in all cause mortality (random effects model OR 0.73 (0.54, 0.98)). Similarly, comprehensive cardiac rehabilitation reduced all cause mortality compared to usual care, but to a lesser degree (OR 0.87 (0.71, 1.05)). Total cardiac mortality was reduced by 31% (random effects model OR 0.69 (0.51, 0.94)) and 26% (random effects model OR 0.74 (0.57, 0.96)) in the exercise only and comprehensive cardiac rehabilitation intervention groups respectively when compared to usual care. Neither intervention had any effect on the ocurrence of non-fatal myocardial infarction. There was a significant net reduction in total cholesterol in the comprehensive cardiac rehabilitation group (pooled WMD random effects model -0.57 mmol/l (-0.83, -0.31)), but not the exercise only rehabilitation group. Similarly, LDL was significantly reduced in the comprehensive cardiac rehabilitation group (pooled WMD random effects model -0.51 mmol/l (-0.82, -0.19). The effect of exercise only rehabilitation or comprehensive cardiac rehabilitation interventions on revascularisation rates, blood pressure or smoking behaviour could not be determined by this meta-analysis due to the small number of trials reporting these outcomes and heterogeneity between trials. It was not possible to combine the data from studies reporting HRQoL as an outcome. Eighteen different instruments were used to assess HRQoL in the 11 studies reporting it as an outcome. The data are presented qualitatively, only one trial reporting significant improvements with the intervention. REVIEWER'S CONCLUSIONS: Exercise-based cardiac rehabilitation appears to be effective in reducing cardiac deaths but the evidence base is weakened by poor quality trials. It is not clear from this review whether exercise only or a comprehensive cardiac rehabilitation intervention is more beneficial. The population studied in this review is still predominately male, middle aged and low risk. Identification of the ethnic origin of the participants was seldom reported. (ABSTRACT TRUNCATED)

Coronary Disease↗

PubMed1994

Cardiovascular responses to exercise. Effects of aging and exercise training in healthy men.

BACKGROUND: Cardiac aging alters many of the acute responses to exercise stress, but the extent to which chronic exercise (ie, training) can alter or improve the effects of aging in humans is largely unknown. METHODS AND RESULTS: Cardiovascular responses to graded supine exercise stress (beginning at 200 kpm and increasing by 200 kpm every 3 minutes till exhaustion) were assessed using radionuclide ventriculography in 13 older (age, 60 to 82 years) and 11 young (age, 24 to 32 years) rigorously screened healthy men before and after 6 months of endurance training. Repeated-measures ANOVA was used to test significance. During exercise, the old group had a lesser increase in heart rate (+105% old versus +166% young), a greater increase in mean blood pressure (+35% old versus +22% young), lesser increases in ejection fraction (+3 ejection fraction units old versus +11 units young) and peak ejection rate (+62% old versus +119% young), a greater increase in end-diastolic volume index (+8% old versus -10% young), a lesser fall in end-systolic volume index (-0% old versus -32% young), and a lesser increase in cardiac index (+135% old versus +189% young) (all P < .01 young/old versus exercise stage). Stroke volume index response to exercise was not different with aging (+14% old versus +6% young, P = NS). Exercise training increased maximal oxygen intake by 21% in the older group (28.9 +/- 4.6 to 35.1 +/- 3.8 mL.kg-1.min-1, P < .001) and by 17% in the young (44.5 +/- 5.1 to 52.1 +/- 6.3 mL.kg-1.min-1, P < .001) and increased peak workload by 24% in the old and 28% in the young. Exercise training had no differential effects on old versus young men. Among all subjects, training significantly reduced the resting heart rate by 12% (-8 beats per minute) and increased resting end-diastolic volume index by 13% (+9 mL/M2) and resting stroke volume index by 18% (+7 mL/M2) (all P < .01). At peak exercise, cardiac index increased by 16% (+1.07 L.M-2.min-1) compared with before training, which was the result of an increase in stroke volume of 18% (+7 mL/M2) (P < .001); peak heart rate was unchanged. The increase in stroke volume index at peak exercise was the result of both a 12% increase in end-diastolic volume index (+8 mL/M2) (P < .01) and an increase in ejection fraction (+3 ejection fraction units) (P < .05) at peak exercise. The increased ejection fraction at peak exercise occurred despite a 9% increase in systolic blood pressure (+18 mm Hg) (P < .01), suggesting an increase in contractility. Thus, both the young and old increased peak exercise cardiac output by use of the Frank-Starling mechanism (ie, cardiac dilatation) as well as an increase in ejection fraction. CONCLUSIONS: We conclude that there is an age-associated decline in heart rate, ejection fraction, and cardiac output responses to supine exercise in healthy men. Although the stroke volume responses of the young and old are similar, the old tend to augment stroke volume during exercise more through cardiac dilatation, with an increase in end-diastolic volume (+8%) but without much change in ejection fraction (+3 ejection fraction units), whereas the young rely more on an increase in the ejection fraction (+11 ejection fraction units) with no cardiac dilatation (-10%). Despite the significant cardiovascular changes that occur in the response to a single bout of exercise with aging, adaptations to chronic exercise training were not different with aging and included improvements in maximal workload and increases in ejection fraction, stroke volume index, and cardiac index at peak exercise.

Adult↗

PubMed2001

Effects of prior exercise and recovery duration on oxygen uptake kinetics during heavy exercise in humans.

Prior heavy exercise (above the lactate threshold, LT) reduces the amplitude of the pulmonary oxygen uptake (VO2) slow component during heavy exercise, yet the precise effect of prior heavy exercise on the phase II VO2 response remains to be established. This study was designed to test the hypotheses that (1) prior heavy exercise increases the amplitude of the phase II VO2 response independently of changes in the baseline VO2 value and (2) the effect of prior exercise depends on the amount of external work done during prior exercise, irrespective of the intensity of the prior exercise. Nine subjects performed two 6 min bouts of heavy cycling exercise separated by 6 min baseline pedalling recovery (A), two 6 min heavy exercise bouts separated by 12 min recovery (6 min rest and 6 min baseline pedalling, B), and a bout of moderate exercise (below the LT) in which the same amount of external work was performed as during the prior heavy exercise, followed by 6 min heavy exercise (C). In both tests A and B, prior heavy exercise significantly increased the absolute VO2 amplitude at the end of phase II (by approximately 150 ml x min(-1)), and reduced the amplitude of the VO2 slow component by a similar amount. Following 12 min of recovery (B), baseline VO2, but not blood [lactate], had returned to pre-exercise levels, indicating that these effects occurred independently of changes in baseline VO2. Prior moderate exercise (C) had no effect on either the VO2 or blood [lactate] responses to subsequent heavy exercise. The VO2 response to heavy exercise was therefore dependent on the intensity of prior exercise, and the effects on the amplitudes of the phase II and slow VO2 components persisted for at least 12 min following prior heavy exercise.

Adult↗

PubMed1994

Supine exercise during lower body negative pressure effectively simulates upright exercise in normal gravity.

Exercise within a lower body negative pressure (LBNP) chamber in supine posture was compared with similar exercise against Earth's gravity (without LBNP) in upright posture in nine healthy male volunteers. We measured footward force with a force plate, pressure in soleus and tibialis anterior muscles of the leg with transducer-tipped catheters, calf volume by strain gauge plethysmography, heart rate, and systolic and diastolic blood pressures during two conditions: 1) exercise in supine posture within an LBNP chamber during 100-mmHg LBNP (exercise-LBNP) and 2) exercise in upright posture against Earth's gravity without LBNP (exercise-1 G). Subjects exercised their ankle joints (dorsi- and plantarflexions) for 5 min during exercise-LBNP and for 5 min during exercise-1 G. Mean footward force produced during exercise-LBNP (743 +/- 37 N) was similar to that produced during exercise-1 G (701 +/- 24 N). Peak contraction pressure in the antigravity soleus muscle during exercise-LBNP (115 +/- 10 mmHg) was also similar to that during exercise-1 G (103 +/- 13 mmHg). Calf volume increased significantly by 3.3 +/- 0.5% during exercise-LBNP compared with baseline values. Calf volume did not increase significantly during exercise-1 G. Heart rate was significantly higher during exercise-LBNP (99 +/- 5 beats/min) than during exercise-1 G (81 +/- 3 beats/min). These results indicate that exercise in supine posture within an LBNP chamber can produce similar musculoskeletal stress in the legs and greater systemic cardiovascular stress than exercise in the upright posture against Earth's gravity.

Adult↗

PubMed2003

Effect of pre-exhaustion exercise on lower-extremity muscle activation during a leg press exercise.

The purpose of this study was to investigate the effect of pre-exhaustion exercise on lower-extremity muscle activation during a leg press exercise. Pre-exhaustion exercise, a technique frequently used by weight trainers, involves combining a single-joint exercise immediately followed by a related multijoint exercise (e.g., a knee extension exercise followed by a leg press exercise). Seventeen healthy male subjects performed 1 set of a leg press exercise with and without pre-exhaustion exercise, which consisted of 1 set of a knee extension exercise. Both exercises were performed at a load of 10 repetitions maximum (10 RM). Electromyography (EMG) was recorded from the rectus femoris, vastus lateralis, and gluteus maximus muscles simultaneously during the leg press exercise. The number of repetitions of the leg press exercise performed by subjects with and without pre-exhaustion exercise was also documented. The activation of the rectus femoris and the vastus lateralis muscles during the leg press exercise was significantly less when subjects were pre-exhausted (p < 0.05). No significant EMG change was observed for the gluteus maximus muscle. When in a pre-exhausted state, subjects performed significantly (p < 0.001) less repetitions of the leg press exercise. Our findings do not support the popular belief of weight trainers that performing pre-exhaustion exercise is more effective in order to enhance muscle activity compared with regular weight training. Conversely, pre-exhaustion exercise may have disadvantageous effects on performance, such as decreased muscle activity and reduction in strength, during multijoint exercise.

Adult↗