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PubMedDate not supplied

Effects of intensity and duration of exercise on differential leucocyte count.

BACKGROUND: Increases in neutrophils, lymphocytes and monocytes account for the exercise induced leucocytosis. Effects of intensity and duration of exercise on differential leucocytes count were observed in this study. METHODS: Two groups of normal healthy male adult subjects were exercised on treadmill for different duration and intensities. Group-I subjects (n = 15) exercised by running for a duration of 2-3 minutes, at 7% grade (4 degree inclination) and at speed ranging from 7.5 to 9 Km/hour, while group-II subjects (n = 15) walked on treadmill for a duration of 7-10 minutes at zero grade and at Speed ranging from 5 to 6 Km/hour. Blood drop for differential leucocyte count was taken from fingertip before exercise, immediately after and 30 minutes after exercise. RESULTS: In group-I subjects neutrophils were increased by 5.97% immediately after exercise and decreased by 13.47% after 30 minutes rest. Therefore neutrophils were 8.454% below baseline (p < 0.001) 30 minutes after exercise. Lymphocytes were increased by 19.57%, 30 minutes after exercise and were 17.73% above baseline (p < 0.001). Eosinophils were increased by 38.04% after 30 minutes rest and were 33.33% below baseline (p < 0.01). Basophils were 50.18% less (p < 0.01) 30 minutes after exercise than pre-exercise. In-group II neutrophils were significantly increased by 4.30%, immediately after exercise and then decreased significantly by 6.01% after 30 minutes rest. On the other hand lymphocytes were significantly decreased by 11.98%, immediately after exercise and then increased significantly by 12.37%, after 30 minutes rest. CONCLUSIONS: It clearly indicates that the exercise of high intensity and lesser duration has greater effect on neutrophil count. The increase in lymphocyte count, 30 minutes after exercise indicate that exercise of low intensity and longer duration is helpful in improving acquired immunity.

Adult↗

PubMed1991

The metabolic consequences of low and moderate intensity exercise with or without feeding in lean and borderline obese males.

The purpose of this study was to investigate the role of exercise intensity on the post-exercise thermogenic effect (PETE), with or without feeding, in five lean (less than 15 percent body fat) and five borderline obese (between 20 and 25 percent body fat) individuals when the total caloric expenditure during exercise was equated to 720 kcal by adjusting exercise duration. Each subject participated in six testing sessions, including the measurement of resting metabolic rate (RMR), dietary induced thermogenesis (DIT) following a 720 kcal liquid meal, and four exercise trials including: (1) exercising on a treadmill at both 30 percent and 60 percent of VO2 max followed by a 720 kcal liquid meal (30F and 60F); and (2) exercising on a treadmill at both 30 percent and 60 percent of VO2 max followed by a non-caloric liquid meal substitute (water) matched by volume to the caloric liquid meal (30NF and 60NF). Indirect calorimetry was used to determine metabolic rate prior to each treatment (0-30 min RMR) and at 0-30, 50-60, 80-90, 110-120, 140-150, and 170-180 min following the feeding, exercise only, or exercise and feeding treatments. A significant difference in the post-exercise oxygen consumption was found between the two calorically equated exercise bouts (720 kcal) at 30 percent and 60 percent of each subject's VO2 max without feeding when all measurement periods following exercise were averaged together (60NF = 13.5 percent increase and 30NF = 5.5 percent). This difference was observed in both the lean and borderline obese subjects, with no significant difference between the two groups. In addition, when walking at either 30 percent or 60 percent of VO2 max preceded feeding, a significant attenuation in the rise of post-feeding RER values was observed in both groups with the higher exercise intensity showing the greatest RER attenuation when compared to the DIT trial. These results suggest that exercise intensity may play a significant role independent of the total energy expenditure in potentiating a person's post-exercise oxygen consumption rate and post-exercise substrate utilization for periods of up to 180 mins.

Adult↗

PubMed1988

Cardiovascular effects of static and dynamic exercise.

The cardiovascular response to static exercise has often been quantified on the basis of a comparison between static handgrip and dynamic cycling exercise. It is then difficult to make precise comparisons because the physical units of work are not compatible. If the data from dynamic exercise can be used to predict the cardiovascular response to zero movement (static exercise) this would suggest that static exercise is not fundamentally different from dynamic exercise. Using leg extension exercise which lasted for 1 min, a set of weights was lifted repeatedly 50 times/min, through three different distances. On each occasion, the heart rate, systolic time intervals (STI) and systemic arterial blood pressure were monitored non-invasively. Regression analysis of heart rate (HR) or blood pressure (BP) against the distance moved by the weights was used to predict the heart rate or blood pressure that would be expected for static exercise. In addition the same responses were measured following 1 min of static exercise during which the weights were held up but not moved. Five subjects, trained in leg extension exercise, completed the four exercise sessions in a random order. A constant force was produced in each variant of the protocol and in the static exercise it amounted to 50% maximal voluntary contraction (MVC). The forces developed and the distance the weights were lifted were monitored. During this sustained static exercise at relatively low intensity the cardiovascular changes could be predicted from the responses induced by dynamic exercise. It is suggested that other factors are important in determining the cardiovascular response to exercise, not simply the mode.

Adult↗

PubMed1993

Relation between left ventricular shape and exercise capacity in patients with left ventricular dysfunction.

OBJECTIVES: The aim of this study was to identify dynamic predictors of exercise duration in patients with systolic left ventricular dysfunction and to test the hypothesis that left ventricular shape is an independent determinant of exercise duration in these patients. BACKGROUND: Measurements of left ventricular volumes and ejection fraction at rest do not predict exercise capacity in patients with systolic left ventricular dysfunction. Left ventricular shape at rest has been reported to be an independent determinant of exercise duration in these patients. The significance of alterations in left ventricular shape that occur during dynamic exercise has not been investigated. METHODS: Twenty-one patients with a documented ejection fraction < 40% performed symptom-limited graded upright bicycle exercise with simultaneous quantitative two-dimensional echocardiography. End-diastolic volume, end-systolic volume, stroke volume, ejection fraction and sphericity index were measured at rest and peak exercise. RESULTS: Eleven patients exercised beyond stage II (6 min, 50 W), averaging 8.9 +/- 1.9 min; 10 patients were unable to complete stage II, averaging 4.9 +/- 0.9 min. No patient developed clinical evidence of ischemia during the exercise period. Of the echocardiographic variables considered, only end-systolic and end-diastolic sphericity indexes at peak exercise (r = 0.809 and 0.711, respectively) and the change in end-systolic sphericity index during exercise (r = 0.697) were strongly correlated with exercise duration. CONCLUSIONS: Conventional descriptors of left ventricular function are poor predictors of exercise capacity. Dynamic changes in heart shape correlate strongly with exercise duration and may be important determinants of exercise capacity in patients with systolic left ventricular dysfunction.

Adult↗

PubMed2004

Exercise patterns and cardiovascular fitness of patients with peripheral arterial disease.

Peripheral arterial disease (PAD) is characterized by walking impairment as the result of claudication, which is improved by exercise. Few studies have examined the impact of existing exercise patterns in community-dwelling patients with PAD on cardiovascular fitness and absolute claudication distance (ACD). This descriptive study examines exercise patterns, walking distance, and cardiovascular fitness in a sample of community-dwelling older adults with PAD. Approximately 50% of subjects reported walking 4 (+/-2) days per week for 38 +/- 24 minutes. ACD (exercisers = 459.9 +/- 272; non-exercisers = 351.2 +/- 266.3, P = .06) and initial claudication distance (exercisers = 198.5 +/- 139.7; non-exercisers = 138.7 +/- 95.8 P = .02) were similar between groups. The workload accomplished was approximately 4.1-4.7 metabolic equivalents. Resting heart rate (HR) was associated with initial claudication distance ( r = -.37, P = .001) and ACD ( r = -.46, P < .01) and was lower in the group of exercisers versus the non-exercisers ( P = .05). Mean resting SBP was elevated and continued to increase at peak exercise with no difference between groups ( P = .75). Quality of life was poor for both groups. Simultaneous multiple regression analysis was performed to determine predictors of peak exercise HR. The model included gender, age, current exercise, ankle-brachial index, coronary artery disease, beta blockers, ACD, and atrial fibrillation (R = 44%, P = .01). Higher peak exercise HR was associated with older age, female gender, no beta blockers, and greater ACD ( P < .01). The findings from this descriptive study demonstrate the need for larger long-term studies to address issues of exercise adherence and the psychologic and functional benefits of exercise.

Activities of Daily Living↗

PubMed2000

Prolonged recovery of cardiac output after maximal exercise in patients with chronic heart failure.

OBJECTIVES: The aim of this study was to characterize the kinetics of cardiac output during recovery from maximal exercise in patients with chronic heart failure (CHF). BACKGROUND: Recent studies have shown that oxygen uptake kinetics during recovery from exercise are delayed in patients with CHF. However, the kinetics of cardiac output during recovery from maximal exercise in CHF has not been examined. METHODS: Thirty patients with CHF performed maximal upright ergometer exercise with respiratory gas analysis. Kinetics of oxygen uptake (VO2) and carbon dioxide output (VCO2) during recovery were characterized by T1/2, the time to reach 50% of the peak values. Cardiac output was measured at 1-min intervals during exercise and recovery. Kinetics of cardiac output during recovery were characterized by the ratios of cardiac output during the first 4 min of recovery to cardiac output at peak exercise. Overshoot of cardiac output was defined as a further increase in cardiac output at 1 min of recovery above the cardiac output at peak exercise. RESULTS: Both T1/2 VO2 and T1/2 VCO2 increased as CHF worsened. The ratios of cardiac output during recovery to cardiac output at peak exercise were significantly correlated with T1/2 VO2 (r = 0.47 to 0.62, p < 0.05) and T1/2 VCO2 (r = 0.40 to 0.70, p < 0.05). There was a negative correlation between cardiac index at peak exercise and both T1/2 VO2 (r = -0.65, p < 0.001) and T1/2 VCO2 (r = -0.60, p < 0.001). Overshoot of cardiac output was recognized in 11 of 30 patients. Cardiac index at peak exercise was significantly lower in patients with overshoot (4.5 +/- 0.9 L/min/m2) than in those without overshoot (6.1 +/- 2.1 L/min/m2, p < 0.05). However, because of a continued increase in cardiac output at 1 min of recovery in patients with overshoot, there were no differences in cardiac index after the first minute of recovery. Heart rate at peak exercise and recovery of heart rate did not differ between these groups. Overshoot of cardiac output was caused by a rebound increase in stroke volume which was due to a reduction in systemic vascular resistance. CONCLUSIONS: Prolonged kinetics of VO2 or VCO2 during recovery from maximal exercise represent impairment of circulatory response to exercise and delayed recovery of cardiac output after exercise. Overshoot of cardiac output at 1 min of recovery was characteristic of severe CHF with poor cardiac output response to exercise.

Analysis of Variance↗

PubMed2000

Ambulatory blood pressure after acute exercise in older men with essential hypertension.

We sought to determine whether reductions in blood pressure in hypertensives after acute exercise persist for more than the 2 to 3 h found in controlled laboratory settings. Subjects (n = 11) were obese (32 +/- 4% body fat), sedentary (VO2max 27 +/- 4 mL/kg/min) 60 +/- 6-year-old men with stage 1 or 2 essential hypertension. Ambulatory blood pressure was recorded on 1 day preceded by 45 min of 70% VO2max treadmill exercise and on another day not preceded by exercise. Systolic blood pressure was lower by 6 to 13 mm Hg for the first 16 h after exercise (P < .05) compared to the day without prior exercise. Twenty-four-hour, day, and night average systolic blood pressures were significantly lower on the day after exercise. There was a trend for peak systolic blood pressure to be lower during the entire 24 h and the day portion of the recording; peak systolic blood pressure was significantly lower during the night portion of the recording after exercise. Systolic blood pressure load (percent of systolic blood pressure readings >140 mm Hg) was reduced during the entire 24 h and the day portion of the recording after exercise. Diastolic blood pressure was lower for 12 of the first 16 h after acute exercise (hours 0 to 4, 5 to 8, 13 to 16) (P < .05) compared to the day without prior exercise. Twenty-four-hour, day, and night average diastolic blood pressure was also significantly lower on the recording after exercise. Peak diastolic blood pressure was lower over the entire 24-h period. Diastolic blood pressure load (percent of diastolic blood pressure readings >90 mm Hg) was lower during the entire 24 h and the day portion of the day after exercise. Preliminary data also suggest that common genetic polymorphisms at the angiotensinogen, lipoprotein lipase, and angiotensin converting enzyme loci may affect the blood pressure-lowering response after acute exercise. Thus, in sedentary, obese hypertensive men a single aerobic exercise session reduced blood pressure enough to result in significantly lower 24-h average systolic, diastolic, and mean arterial blood pressure. This could result in a reduced cardiovascular load during the 24 h after acute exercise in older hypertensive men.

Aged↗

PubMed2002

Exercise prescription based upon cardiac vagal activity for middle-aged obese women.

OBJECTIVE: The purposes of this study were to examine a new method to determine exercise intensity for obese people based on the cardiac vagal activity and to determine the effect of this approach on myocardial stress. SUBJECTS: Forty-three middle aged obese female volunteers (age 43.7+/-6.5 y; height 1.56+/-0.05 m; body mass 66.5+/-9.3 kg; body mass index 27.3+/-2.8 kg m(2); percentage body fat 40.7+/-5.9%). MEASUREMENT: In the first experiment, 43 subjects performed a ramp exercise test on a bicycle ergometer with measurement of ECG and gas exchange parameters. In the second experiment, 11 subjects performed 45 min of constant walking exercise on a treadmill at a level corresponding to exercise intensity determined by vagal activity obtained from a ramp bicycle test. Blood pressure, endothelin 1 (ET-1), catecholamine, atrial natriuretic peptide (ANP), and brain natriuretic peptide (BNP) were measured before and after exercise. RESULTS: The heart rate variability power decreased with increasing work rate, and changed little after reaching individual-specific work rate. We presumed that vagal activity disappeared at this point and that the heart rate at this exercise intensity was determined as the vagal activity threshold (T(VA)). The results showed a significant positive correlation (r=0.742, P<0.0001) between T(VA) and ventilatory threshold (VT) heart rates, although the mean heart rate of T(VA) (114.3+/-8.5 beats/min) was significantly lower (P<0.001) than that at VT (119.0+/-11.7), suggesting the cardiac vagal withdrawal occurred prior to the onset of lactate acidosis (lactic acid accumulation). Furthermore, exercise intervention experiment at T(VA) indicated that ET-1, catecholamine and BNP levels were not significantly different before and after exercise. However, ANP levels increased significantly after exercise (pre-exercise 18.6+/-5.38 vs post-exercise 44.0+/-24.87 pg/ml, P<0.001), which in turn brought about a significant post-exercise reduction in the blood pressure (SBP 117.6+/-13.7 vs 110.5+/-7.4 mmHg, P<0.05; DBP 78.6+/-6.7 vs 73.5+/-6.6 mmHg, P<0.01). CONCLUSION: Our data suggest that it is possible to determine the exercise intensity (T(VA)) on the basis of cardiac vagal response. These results also suggest that exercise at T(VA) level is a safe exercise intensity in the light of cardiac stress, and that T(VA) may be recommended for obese people who might possess lower cardiac sympatho-vagal activity.

Adult↗

PubMed2002

Muscle activation during exercises to improve trunk stability in men with low back pain.

OBJECTIVES: To evaluate the relative activation amplitudes from 3 abdominal and 2 trunk extensor muscle sites of persons with low back pain (LBP) performing the pelvic-tilt, the abdominal-hollowing, and level 1 of the trunk stability test (TST) exercises and to compare the activation amplitudes among muscle sites and exercises. DESIGN: A prospective, comparative, repeated-measures design. SETTING: Motion analysis research laboratory. PARTICIPANTS: Fourteen men with LBP (mean duration, 8y; mean age +/- standard deviation, 39+/-5y). INTERVENTIONS: Subjects performed 3 exercises in random order while surface electromyograms were recorded from 5 muscle sites: lower and upper rectus abdominus, external oblique, erector spinae, and multifidus. The exercises were divided into 2 phases: a movement phase and a stabilization phase. The root-mean-square (RMS) electromyographic amplitude for each phase was calculated and normalized to the highest RMS amplitude from a series of 4 exercises, which attempted to elicit maximal voluntary isometric contractions (MVICs) for each muscle. A 2-factor, repeated-measures analysis of variance (ANOVA) tested the muscle by exercise interaction and the 2 main effects for each phase separately. MAIN OUTCOME MEASURES: Normalized RMS amplitude was the main dependent variable. The ensemble-average profiles for each muscle were calculated to examine the phasing of activation throughout the exercises. RESULTS: The ANOVA revealed a statistically significant muscle-by-exercise interaction (P<.05) for both phases, which showed that the 3 exercises; recruited the 5 muscle sites using different patterns of relative amplitudes. The external oblique muscle site was activated to higher amplitudes than the other 4 muscle sites for all 3 exercises; the highest normalized RMS activity occurred at the external oblique during the pelvic tilt (32% MVIC). The phasic patterns among the 5 muscle sites were not consistent for the TST but were consistent among the 5 sites for the other 2 exercises. CONCLUSIONS: None of the exercises recruited the abdominal muscles to intensities deemed adequate for strengthening. The TST challenges the coordination of muscle activity during the leg-loading task (stabilization phase) as evidenced by changes in amplitudes over the total exercise time for the external oblique site, but not the other 4 sites. All 3 exercises could be used as initial exercises in a dynamic stability progression when low-recruitment amplitudes of specific muscles were the objective but not for strengthening.

Abdominal Muscles↗

PubMed2002

The decrease in VO(2) slow component induced by prior exercise does not affect the time to exhaustion.

In previous studies decreases in the VO(2) slow component were observed after prior heavy exercise. The observed effects after prior low-intensity exercise were rather controversial. The purpose of the present study was to more thoroughly examine the effects of prior low-intensity exercise on the VO(2) slow component. Furthermore, it has been suggested that the VO(2) slow component may be a determinant of exercise tolerance. Therefore we tested the hypothesis whether an attenuated VO(2) slow component induced by prior exercise could affect the time to exhaustion. Ten subjects performed four exercise protocols consisting of heavy cycling exercise (95 % VO(2)peak) until exhaustion. This constant-load exercise was performed without prior exercise (protocol NPE), or was preceded by 6 min heavy cycling exercise (protocol 6HPE), 12 min low-intensity cycling exercise (protocol 12LPE) or 6 min low-intensity cycling exercise (protocol 6LPE). The VO(2) slow component quantified as Delta VO(2 (end-2)) (669 +/- 90 ml x min (-1) in NPE) was significantly reduced after heavy as well as low-intensity exercise (respectively 47 %, 29 % and 17 % in 6HPE, 12LPE and 6LPE). This reduction lead to a significantly lower end VO(2) in 6HPE and 12LPE. The time to exhaustion (594 +/- 139 s in NPE), however, was unaffected by prior exercise rejecting our hypothesis that the attenuated VO(2) slow component could improve the capability to sustain exercise performance.

Adaptation, Physiological↗

PubMedDate not supplied

Pulmonary function response to equivalent doses of ozone consequent to intermittent and continuous exercise.

The effects on pulmonary function of inhaling the same effective dose of ozone, as well as subjective responses during continuous exercise and intermittent exercise, were studied in 12 aerobically trained men. Each subject completed 1 h of continuous exercise at work rates that elicited a mean minute ventilation of 60 l/min, and two additional 2-h intermittent exercise exposures eliciting a mean exercise minute ventilation of 45-47 l/min (i.e., total minute ventilation for each protocol was approximately 3,600 l). Subjects were exposed in randomized sequence to 0.30 ppm ozone on three occasions and to filtered air on three occasions. Forced expiratory volume in 1 s decrements of -17.6%, -17.0%, and -17.9%, respectively, for the 1-h continuous exercise exposure and the two 2-h intermittent exercise exposures to 0.30 ppm ozone were significantly different. Exposure to ozone caused significant differences between postexposure subjective symptom responses; that is, responses associated with continuous exercise were greater than those for either intermittent exercise protocol. However, the overall symptom severity responses during the last minute of exercise for the two intermittent exercise protocols (at 90 and 105 min, respectively) were not significantly different from the continuous exercise postexposure value. The findings indicate that when the ozone effective dose is equivalent at a given ozone concentration, there is no difference between pulmonary function responses to continuous exercise or intermittent exercise exposures of 2-h duration (or less), although subjective symptoms are reduced somewhat during the last rest period of intermittent exercise.

Adult↗

PubMed1998

Cardio-respiratory load of exercise training in patients with severe COPD.

The effect of physical training depends on the intensity at which exercise is performed. Patients with chronic obstructive pulmonary disease (COPD) may not tolerate high exercise intensities during training due to breathlessness. The purpose of the present study was to investigate the cardiorespiratory load of exercise training, during pulmonary rehabilitation, in patients with severe COPD. We also studied the effects of pulmonary rehabilitation on maximum exercise performance. Thirteen patients with stable COPD (FEV1 (S.D.) 1.0 (0.3) L) performed an incremental cycle exercise test at baseline and after a 10 week in-patient pulmonary rehabilitation programme. Exercise training consisted of dynamic and isometric strength training exercises, and training of specific daily life activities. Training sessions were held 5 days per week for 10 weeks. Heart rate (HR) and dyspnoea ratings (Borg scale) were measured during one session in the second or third week of training, and were compared with values obtained during incremental cycle exercise at baseline. The ventilatory load during the training was estimated by using the relationship between HR and minute ventilation (VE) during incremental cycle exercise at baseline. The duration of a training session was 80 (7) min, including periods of rest. The HR during various exercises of the training programme varied between 94 (17) and 103 (14)% of peak HR during incremental cycle exercise. Borg scores during the training varied between 2.0 and 5.7, and were lower than the Borg score at peak exercise (6.5 (2.0)). HR was more than 90% of peak HR during 36 (33) min of the whole training session, which corresponded with a VE of 81 (11)% of peak VE during incremental cycle exercise. Training significantly increased maximum work load (Wmax) from 62 (25) to 73 (21) W (P < 0.05), without any change in peak HR, VE and VO2. In patients with severe COPD, the training intensity in terms of cardio-respiratory load was high in relation to individual maximum values. Pulmonary rehabilitation, including exercise training, improved maximum exercise performance.

Aged↗

PubMedDate not supplied

Predictors of early post-cardiac transplant exercise capacity.

BACKGROUND: This study was conducted to identify which pre- and perioperative clinical parameters were predictive of predischarge submaximal exercise capacity and early postdischarge maximal exercise capacity in cardiac transplant recipients. METHODS: We studied 24 patients (mean age = 46; 25% African American) who underwent cardiac transplantation followed by an early (immediately posttransplant) postoperative exercise training program. The patients' submaximal exercise capacity was measured at hospital discharge (25 days posttransplant) using the 6-minute distance walk test. Maximal cardiopulmonary exercise testing was done within 4 months of hospital discharge (68 days) to measure peak exercise oxygen consumption (VO2) and to estimate peak exercise capacity as measured by metabolic equivalents (METs). Six clinical variables were assessed for their relationship with predischarge submaximal exercise capacity and 10 clinical variables were evaluated for their relationship with early posttransplant maximal exercise capacity. RESULTS: Predischarge submaximal exercise capacity was correlated with postdischarge estimated METs (r = 0.43; P = 0.04). No predictors of predischarge submaximal exercise capacity were identified. Predictors of estimated peak exercise METs following discharge were younger age, longer time since resolution of rejection, and shorter postoperative hospitalization. Younger age was the only predictor of peak VO2. CONCLUSION: Postoperative physical training may improve exercise capacity early after transplantation and minimize effects of preoperative clinical factors that could negatively affect exercise capacity. Interpretation of these results, however, is limited by the small sample and absence of a nonexercising control group. Older recipients, those with a longer length of hospital stay, and shorter duration of time since resolution of rejection may be at risk of reduced early postoperative maximal exercise capacity. Identification of these predictors is important to maximize early reconditioning efforts and plan outpatient rehabilitation.

Adult↗

PubMed2002

Effects of arm exercise on serum glucose response in type 2 DM patients.

The aims of the study were to examine the influence of upper extremity exercise on glucose response and to establish a predictive model of changes in serum glucose under different exercise intensities and durations. Thirty-three type 2 DM patients who met the selection criteria were selected. An arm cycle ergometer exercise test was conducted, and then 12 arm exercise sessions were arranged based on different exercise intensities (40%, 60%, and 80% of maximal workload) and exercise durations (10, 20, 30, and 40 min). Serum glucose levels were measured before and after each exercise session. Serum glucose levels significantly decreased after arm exercise regardless of different intensities or durations. However, no interaction effect (intensity x duration) or main effect in exercise intensity was observed, but a significant main effect in exercise duration was observed (F = 11.756, p <.0001). Also exercise duration was a significant predictor of serum glucose changes after arm exercise. These results suggest that arm exercise can play a useful role in glycemic control for type 2 DM patients and exercise duration is a key factor in determining serum glucose response under upper-extremity exercise.

Analysis of Variance↗

PubMed2000

Relation between duration and intensity of first exercise and "warm up" in ischaemic heart disease.

OBJECTIVE: To determine the importance of the duration and intensity of "warm up" exercise for reducing ischaemia during second exercise in patients with exertional angina. DESIGN: Randomised crossover comparison of three warm up exercise protocols. PATIENTS: 18 subjects with stable ischaemic heart disease and > 0.1 mV ST segment depression on treadmill exercise testing. INTERVENTIONS: The warm up protocols were 20 minutes of slow exercise at 2.7 km/h, symptom limited graded exercise for a mean of 7.4 (range 5.0 to 10.5) minutes, and three minutes of symptom limited fast exercise of similar maximum intensity. MAIN OUTCOME MEASURES: ST segment depression during graded treadmill exercise undertaken 10 minutes after each warm up protocol or no warm up exercise. RESULTS: Compared with exercise with no warm up, the duration of graded exercise after earlier slow warm up increased by 4.9% (95% confidence interval (CI), -3.3% to 13.7%), after graded warm up by 10.3% (95% CI, 5.6% to 15.2%), and after fast warm up by 16% (95% CI, 6.2% to 26.7%). ST segment depression at equivalent submaximal exercise decreased after slow warm up by 27% (95% CI, 5% to 44%), after graded warm up by 31% (95% CI, 17% to 44%), and after fast warm up by 47% (95% CI, 27% to 61%). Compared with slow warm up exercise, the more intense graded and fast warm up protocols significantly increased the duration of second exercise (p = 0.0072) and reduced both peak ST depression (p = 0.0026) and the rate of increase of ST depression (p = 0.0069). CONCLUSIONS: In patients with exertional angina the size of the warm up response is related to the maximum intensity rather than the duration of first exercise.

Aged↗

PubMed1992

New redistribution index of nutritive blood flow to skeletal muscle during dynamic exercise.

BACKGROUND: Cardiac output is effectively redistributed to working muscle by regional changes in vascular resistance. However, there has been no suitable method to quantify blood flow distribution to large working and nonworking muscles involved in ergometer or treadmill exercise. METHODS AND RESULTS: To quantify the redistribution of blood flow, we compared thallium activity in a bicycle pedaling leg with that in the contralateral resting leg in 10 normal subjects. The regional thallium activity was expressed as a percentage of the whole-body radioisotope activity. Comparison of thallium activity between legs was performed at rest and at the work rates of anaerobic threshold and peak exercise during one-leg exercise. Thallium distribution of both legs was essentially the same at rest. At the anaerobic threshold, thallium activity increased about threefold to fourfold in the exercising thigh and about twofold in the exercising calf. The thallium distribution in these muscles at peak exercise was the same as at the anaerobic threshold. In the nonexercising calf, thallium distribution during exercise decreased significantly, and it was unchanged in the nonexercising thigh. Consequently, the ratio of thallium activity between the exercising and nonexercising thighs increased from 1.1 +/- 0.1 to 4.0 +/- 0.9 at the anaerobic threshold and to 3.3 +/- 0.6 at peak exercise. Similarly, the ratio between the exercising and nonexercising calves increased from 1.0 +/- 0.0 to 3.8 +/- 1.3 at the anaerobic threshold and to 3.5 +/- 1.0 at peak exercise. The ratios at peak exercise, however, did not differ significantly from those at the anaerobic threshold. CONCLUSIONS: These findings suggest that the redistribution of blood flow occurs predominantly during mild to moderate exercise; therefore, blood flow in the leg during strenuous exercise would depend primarily upon an increased cardiac output. Thus, the thallium activity ratio of exercising and nonexercising legs reflects the difference in vascular tone of each leg and could provide a noninvasive and quantitative index of blood flow redistribution.

Adult↗

PubMed1995

Abnormal forearm vascular responses during dynamic leg exercise in patients with vasovagal syncope.

BACKGROUND: We have reported previously that in some patients with normal hearts who present with exercise syncope, abnormal forearm vasodilation is seen during leg exercise and tilt table tests are positive. This suggests that exercise syncope may be a variant of vasovagal syncope. In this study we tested the hypothesis that there is loss of the normal forearm vasoconstrictor response during dynamic leg exercise in an unselected population of patients with classic vasovagal syncope. METHODS AND RESULTS: We evaluated forearm vascular responses during maximal semierect cycle exercise in 28 consecutive patients with vasovagal syncope and compared them with 30 age-matched control subjects. We also evaluated blood pressure responses during erect treadmill exercise (Bruce protocol). While forearm vascular resistance at rest was similar in the patients with vasovagal syncope and the control group, forearm vascular resistance was markedly lower in the patients than in control subjects at peak exercise (85 +/- 54 versus 149 +/- 94 units, P = .002). Forearm vascular resistance fell by 3 +/- 48% during exercise in patients versus an increase of 135 +/- 103% in control subjects (P < .0001). Systolic blood pressure during erect exercise was lower in patients versus control subjects (155 +/- 32 versus 188 +/- 17 mm Hg, P < .0001). Six of the vasovagal patients complained of exercise syncope or presyncope on specific inquiry, and 4 of these 6 exhibited exercise hypotension during erect treadmill exercise testing. CONCLUSIONS: Patients with vasovagal syncope exhibit a failure of the normal vasoconstrictor response in the forearm during dynamic leg exercise. Exercise syncope and presyncope are not uncommon in unselected patients with classic vasovagal syncope, as is exercise hypotension.

Adult↗

PubMed2006

The effects of aerobic and resistance exercises in obese women.

OBJECTIVE: To compare the effects of aerobic and resistance exercise on weight, muscle strength, cardiovascular fitness, blood pressure and mood in obese women who were not on an energy-restricted diet. DESIGN: Randomized, prospective, controlled trial. SETTING: Department of Physical Medicine and Rehabilitation, University Hospital. SUBJECTS: Sixty obese women were assigned to one of three groups: aerobic exercise (n = 20), resistance exercise (n = 20) and control group (n = 20). INTERVENTIONS: The aerobic exercise group performed both walking and leg cycle exercise with increasing duration and frequency. The resistance exercise group performed progressive weight-resistance exercises for the upper and lower body. MAIN OUTCOME MEASURES: Before and after a 12-week period, all subjects were evaluated by anthropometric measurement, rating of mood, cardiorespiratory capacity and maximum strength of trained muscles. RESULTS: After a 12-week training period, subjects in the resistance group showed significant improvement in one-repetition maximum test of hip abductors (7.95+/-3.58 kg), quadriceps (14+/-7.18 kg), biceps (3.37+/- 2.84 kg) and pectorals (8.75+/-5.09 kg) compared with those in the control group (P < 0.001). VO2 max increased (0.51+/-0.40) and Beck Depression Scale scores decreased (-5.40+/-4.27) in the aerobic exercise group compared with the control group, significantly (P < 0.001). Only in hip abductor muscle strength was there a significant increase in the resistance exercise group compared with the aerobic exercise group (P < 0.05). CONCLUSION: Both aerobic exercise and resistance exercise resulted in improved performance and exercise capacity in obese women. While aerobic exercise appeared to be beneficial with regard to improving depressive symptoms and maximum oxygen consumption, resistance exercise was beneficial in increasing muscle strength.

Adult↗

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