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 307 records · Page 17Linked to original sources

PubMed2001

Predictors of older primary care patients' participation in a submaximal exercise test and a supervised, low-impact exercise class.

OBJECTIVES: This study is an investigation of physical activity promotion among a nonvolunteer sample of community-dwelling, older, urban primary care patients. Our primary interest was in the rates of exercise test and class participation. Of secondary interest were the medical record and baseline survey predictors of test and class participation. METHODS: The first 500 nonterminally ill women ages 50 years or more with a visit at one of two predominantly African-American, inner-city primary care clinics received a physician screen, a referral to a submaximal exercise test, and, subsequently, a free, supervised exercise program located in a nearby community center. RESULTS: Eighty-one percent were eligible for the exercise test per provider screen. Of these, 29% completed the exercise test and 28% attended at least one exercise class. After 1 year, 9.2% were attending the exercise classes. Higher exercise outcome expectations, not smoking, and clinic site were associated with exercise test and class participation. CONCLUSIONS: Providing free, traditional exercise classes and a primary care referral to the classes resulted in limited physical activity participation among older, urban primary care patients. More development and testing of physical activity promotion programs are needed in this population.

Black or African American↗

PubMed2002

Effect of an acute period of resistance exercise on excess post-exercise oxygen consumption: implications for body mass management.

Studies have shown metabolism to remain elevated for hours following resistance exercise, but none have gone beyond 16 h, nor have they followed a whole body, high intensity exercise protocol. To examine the duration of excess post-exercise oxygen consumption (EPOC) following a period of heavy resistance exercise, seven healthy men [mean (SD) age 22 (3) years, height 177 (8) cm, mass 83 (10) kg, percentage body fat 10.4 (4.2)%] engaged in a 31 min period of resistance exercise, consisting of four circuits of bench press, power cleans, and squats. Each set was performed using the subject's own predetermined ten-repetition maximum and continued until failure. Oxygen consumption ( ) measurements were obtained at consistent times (34 h pre-, 29 h pre-, 24 h pre-, 10 h pre-, 5 h pre-, immediately post-, 14 h post-, 19 h post-, 24 h post-, 38 h post-, 43 h post-, and 48 h post-exercise). Post-exercise measurements were compared to the baseline measurements made at the same time of day. The was significantly elevated ( P<0.05) above baseline values at immediately post, 14, 19, and 38 h post-exercise. Mean daily values for both post-exercise days were also significantly elevated above the mean value for the baseline day. These results suggest that EPOC duration following resistance exercise extends well beyond the previously reported duration of 16 h. The duration and magnitude of the EPOC observed in this study indicates the importance of future research to examine a possible role for high intensity resistance training in a weight management program for various populations.

Adult↗

PubMed1997

Differences in the change in the time course of plasma endothelin-1 and endothelin-3 levels after exercise in humans. The response to exercise of endothelin-3 is more rapid than that of endothelin-1.

Several studies have indicated that endothelin-1 (ET-1) and endothelin-3 (ET-3) are produced by different cells. Although ET-1 is produced by vascular endothelial cells, these cells do not produce ET-3. The presence of ET-3 in the brain of several species suggests that ET-3 is a novel neuropeptide. It is unclear whether there are differences in the release of ET-1 and ET-3 under various physiological conditions in humans. In the present study, we measured the plasma concentrations of both ET-1 and ET-3 before and after endurance exercise on a cycle ergometer. Male athletes exercised on a cycle ergometer for 30 min at intensity of 130% of their individual ventilatory threshold (VT), which is intense exercise. Plasma ET-1 and ET-3 were greatly elevated by exercise, but there was a marked difference in the time-course of the change in plasma concentration between the two peptides. The level of ET-1 peaked 30 min after exercise, whereas that of ET-3 peaked immediately after exercise. Thus, plasma ET-3 increased faster than plasma ET-1 after exercise. The exercise-induced change in the time course in plasma ET-3, but not in ET-1, is similar to that in plasma norepinephrine which is a neurotransmitter, suggesting that the rapid elevation in plasma ET-3 is partly attributable to the neuronal response to exercise. The observed difference in the change in the time course of plasma ET-1 and ET-3 levels suggests that the mechanisms by which exercise alters the release and/or synthesis of these two peptides differ.

Adolescent↗

PubMed1996

Hyperventilation during exercise: independence on exercise-induced bronchoconstriction in mild asthma.

Ventilatory gas exchange during exercise was compared in patients with mild asthma (11 females and 11 males), hyperventilation syndrome (HVS, 11 females), and healthy subjects (11 females and 11 males) in order to assess hyperventilation during exercise and its association with exercise-induced bronchoconstriction. The asthmatics showed decreased working capacity and decreased maximal oxygen consumption, with no evidence of limitation due to impairment of ventilatory capacity. Ventilatory equivalents for CO2 and O2 (VE/VCO2 and VE/VO2) at rest did not differ between the controls and asthmatics, but they were significantly elevated in HVS. In female asthmatics, ventilatory equivalents during exercise were significantly (P < 0.05) elevated compared with those of healthy subjects; in female controls, VE/VCO2 was 30.1 +/- 3.3 at low exercise and 27.4 +/- 6.5 at maximal exercise. In female asthmatics, the corresponding figures were 34.9 +/- 6.1 and 36.7 +/- 5.3. Furthermore, VE/VCO2 individually related to percent of maximal oxygen consumption (VO2max) was significantly increased in female asthmatics both at low and high VO2. The highest ventilatory equivalents were obtained in HVS, 41.7 +/- 6.7 and 43.9 +/- 0.9, respectively. Significant exercise-induced bronchoconstriction (decrease of FEV1 > 15%) was found in 50% of the asthmatics. The ventilatory equivalents did not correlate with exercise-induced changes in FEV1 (r2 < 0.3). Mild exercise-induced hyperventilation which was observed in mild female asthmatics, did not appear to be related to exercise-induced bronchoconstriction.

Adult↗

PubMed2000

Twenty-four hour, ambulatory blood pressure responses following acute exercise: impact of exercise intensity.

OBJECTIVES: Mild to moderate acute, endurance exercise has generally been shown to reduce blood pressure (BP) in hypertensive (HT) individuals. Whether a slightly more strenuous bout of exercise can elicit a greater and more prolonged BP reduction is unknown. Therefore, the purpose of this study was to examine the effects of two, 30-min exercise bouts, conducted at 50% and 75% of maximal oxygen uptake (VO2max), on the quantity and quality of BP reduction over a 24-h period. METHODS: Sixteen, Stage 1 and 2 non-medicated, HT (8 men/8 women) subjects were matched with normotensive (NT) men and women (n = 16). All subjects were evaluated for VO2max with a symptom-limited treadmill test and then completed a 30-min exercise bout at 50% and 75% of VO2max as well as a control (no exercise) session in random fashion on separate days. Twenty-four hour ambulatory BPs were measured after both the exercise and control settings. Data was assessed at 1, 3, 6, 12, and 24 h post-exercise and control session. RESULTS: A repeated-measures ANOVA showed non-significant differences between HT men and women and that both exercise intensities, relative to the control session, significantly (P<0.05) reduced systolic (S) and diastolic (D) BPs. NT subjects showed non-significant reductions following both intensities. The reductions in the HT men and women averaged 4 and 9 mm Hg (SBP)/5 and 7 mm Hg (DBP) for 50% and 75%, respectively. On average, the HT subjects (men and women combined) maintained significant SBP reductions for 13 h after the 75% bout compared to 4 h after the 50% intensity. Likewise, DBP was reduced for an average of 11 h following the 75% bout compared to 4 h after the 50% intensity. CONCLUSIONS: These results suggest that an exercise bout conducted between 50-75% VO2max significantly decreases SBP and DBP in HT subjects and that a greater and longer-lasting absolute reduction is evident following a 75% of maximum bout of exercise.

Adult↗

PubMed2000

Influence of light additional arm cranking exercise on the kinetics of VO2 in severe cycling exercise.

This study examined the influence of light additional arm cranking exercise on the VO2 slow component observed during severe cycling exercise. During incremental tests, eleven triathletes exercised to exhaustion cycling with leg, cranking with arm and combined arm and leg cranking and cycling (arm work-rates being set at the third of leg work rates) to determine arm, leg and combined arm and leg lactate threshold and VO2max. After these incremental tests subjects performed in random order severe exercises until exhaustion at work-rates corresponding to the lactate threshold + 50% of the difference to the work rate associated with VO2max and the lactate threshold, i.e., delta50: 1) with legs only (leg delta50) 2) leg delta50 plus a very light arm cranking exercise at 25 % of the arm lactate threshold (Ldelta50 + A25). VO2 slow component was the increase of VO2 (in ml x min(-1)) between the third and the sixth minute of exercise (deltaVO2 63 min). Results showed 1) Nine of the eleven triathletes had a VO2 slow component in arm delta50; 2) a light cycle arm exercise (25% of lactate threshold) added to a severe leg cycle exercise did not decrease time to exhaustion in severe exercise (493 +/- 154s vs 418 +/- 84, P=0.4); 3) For the five subjects who had a VO2 slow component in leg cycling, the addition of a light arm exercise (25% of arm LT) decreased the VO2 slow component significantly (from 457 +/- 173 ml x min(-1) for leg delta50 to 111 +/- 150 ml x min(-1) for Ldelta50 + A25, Z = -2.0, P = 0.04). In conclusion, light additional arm cranking decreases the VO2 slow component in severe cycling. Further studies are needed to confirm the hypothesis that extra work due to an increasing handgrip on the handlebars may contribute to the VO2 slow component in cycling.

Adult↗

PubMed2001

The inflammatory response to upper and lower limb exercise and the effects of exercise training in patients with claudication.

PURPOSE: We have previously shown that a program of upper limb exercise training can induce significant improvements in walking distance in patients with claudication. This study assessed whether upper limb exercise avoids the systemic inflammatory responses associated with lower limb exercise and also whether the inflammatory response to acute lower limb exertion is modified by a program of supervised exercise training. METHODS: Fifty-two patients with stable intermittent claudication were randomized into two groups who underwent 6 weeks of supervised upper (n = 26) or lower (n = 26) limb cardiorespiratory exercise training. A parallel control group (n = 15) was provided with lifestyle advice only. Neutrophil activation markers (CD11b and CD66b) and plasma levels of von Willebrand factor (marker of endothelial damage) in response to an acute bout of sustained upper and lower limb exercise were assessed before and after the period of training. Plasma levels of soluble E-selectin (marker of endothelial activation) were also determined before and after the training period. RESULTS: An acute bout of sustained lower limb exercise significantly increased the intensity of CD11b and CD66b expression by peripheral blood neutrophils in all groups, whereas upper limb exercise had no effect. Resting neutrophil expression of CD11b and CD66b and circulating von Willebrand factor levels were unaffected by the training program, as were the inflammatory responses to an acute bout of sustained upper and lower limb muscular work, despite the fact that both training programs significantly increased walking distances. CONCLUSIONS: These findings indicate that upper limb exercise training programs may offer certain advantages over currently prescribed lower limb programs. Our results show that exercising nonischemic muscles in a way that promotes improved cardiorespiratory function and walking capacity can avoid the potentially deleterious systemic inflammatory responses associated with lower limb exertion in patients with stable intermittent claudication.

Adult↗

PubMed2005

The interaction of central command and the exercise pressor reflex in mediating baroreflex resetting during exercise in humans.

Central command and the exercise pressor reflex can independently reset the carotid baroreflex (CBR) during exercise. The present investigation assessed the interactive relationship between these two neural mechanisms in mediating baroreflex resetting during exercise. Six men performed static leg exercise at 20% maximal voluntary contraction under four conditions: control, no perturbation; neuromuscular blockade (NMB) induced by administration of the neuromuscular blocking agent Norcuron (central command activation); MAST, application of medical antishock trousers inflated to 100 mmHg (exercise pressor reflex activation); and Combo, NMB plus MAST (concomitant central command and exercise pressor reflex activation). With regard to CBR control of heart rate (HR), both NMB and Combo conditions resulted in a further resetting of the carotid-cardiac stimulus-response curve compared to control conditions, suggesting that CBR-HR resetting is predominately mediated by central command. In contrast, it appears that CBR control of blood pressure can be mediated by signals from either central command or the exercise pressor reflex, since both NMB and MAST conditions equally augmented the resetting of the carotid-vasomotor stimulus-response curve. With regard to the regulation of both HR and blood pressure, the extent of CBR resetting was greater during the Combo condition than during overactivation of either central command or the exercise pressor reflex alone. Therefore, we suggest that central command and the exercise pressor reflex interact such that signals from one input facilitate signals from the other, resulting in an enhanced resetting of the baroreflex during exercise.

Adult↗

PubMed2006

Effects of "priming" exercise on pulmonary O2 uptake and muscle deoxygenation kinetics during heavy-intensity cycle exercise in the supine and upright positions.

We hypothesized that the performance of prior heavy exercise would speed the phase 2 oxygen consumption (VO2) kinetics during subsequent heavy exercise in the supine position (where perfusion pressure might limit muscle O2 supply) but not in the upright position. Eight healthy men (mean +/- SD age 24 +/- 7 yr; body mass 75.0 +/- 5.8 kg) completed a double-step test protocol involving two bouts of 6 min of heavy cycle exercise, separated by a 10-min recovery period, on two occasions in each of the upright and supine positions. Pulmonary O2 uptake was measured breath by breath and muscle oxygenation was assessed using near-infrared spectroscopy (NIRS). The NIRS data indicated that the performance of prior exercise resulted in hyperemia in both body positions. In the upright position, prior exercise had no significant effect on the time constant tau of the VO2 response in phase 2 (bout 1: 29 +/- 10 vs. bout 2: 28 +/- 4 s; P = 0.91) but reduced the amplitude of the VO2 slow component (bout 1: 0.45 +/- 0.16 vs. bout 2: 0.22 +/- 0.14 l/min; P = 0.006) during subsequent heavy exercise. In contrast, in the supine position, prior exercise resulted in a significant reduction in the phase 2 tau (bout 1: 38 +/- 18 vs. bout 2: 24 +/- 9 s; P = 0.03) but did not alter the amplitude of the VO2 slow component (bout 1: 0.40 +/- 0.29 vs. bout 2: 0.41 +/- 0.20 l/min; P = 0.86). These results suggest that the performance of prior heavy exercise enables a speeding of phase 2 VO2 kinetics during heavy exercise in the supine position, presumably by negating an O2 delivery limitation that was extant in the control condition, but not during upright exercise, where muscle O2 supply was probably not limiting.

Adaptation, Physiological↗

PubMed2005

Repeat exercise normalizes the gas-exchange impairment induced by a previous exercise bout in asthmatic subjects.

Twenty-one subjects with asthma underwent treadmill exercise to exhaustion at a workload that elicited approximately 90% of each subject's maximal O2 uptake (EX1). After EX1, 12 subjects experienced significant exercise-induced bronchospasm [(EIB+), %decrease in forced expiratory volume in 1.0 s = -24.0 +/- 11.5%; pulmonary resistance at rest vs. postexercise = 3.2 +/- 1.5 vs. 8.1 +/- 4.5 cmH2O.l(-1).s(-1)] and nine did not (EIB-). The alveolar-to-arterial Po2 difference (A-aDo2) was widened from rest (9.1 +/- 6.7 Torr) to 23.1 +/- 10.4 and 18.1 +/- 9.1 Torr at 35 min after EX1 in subjects with and without EIB, respectively (P < 0.05). Arterial Po2 (PaO2) was reduced in both groups during recovery (EIB+, -16.0 +/- -13.0 Torr vs. baseline; EIB-, -11.0 +/- 9.4 Torr vs. baseline, P < or = 0.05). Forty minutes after EX1, a second exercise bout was completed at maximal O2 uptake. During the second exercise bout, pulmonary resistance decreased to baseline levels in the EIB+ group and the A-aDo2 and PaO2 returned to match the values seen during EX1 in both groups. Sputum histamine (34.6 +/- 25.9 vs. 61.2 +/- 42.0 ng/ml, pre- vs. postexercise) and urinary 9alpha,11beta-prostaglandin F2 (74.5 +/- 38.6 vs. 164.6 +/- 84.2 ng/mmol creatinine, pre- vs. postexercise) were increased after exercise only in the EIB+ group (P < 0.05), and postexercise sputum histamine was significantly correlated with the exercise PaO2 and A-aDo2 in the EIB+ subjects. Thus exercise causes gas-exchange impairment during the postexercise period in asthmatic subjects independent of decreases in forced expiratory flow rates after the exercise; however, a subsequent exercise bout normalizes this impairment secondary in part to a fast acting, robust exercise-induced bronchodilatory response.

Acid-Base Equilibrium↗

PubMed1995

Oxygen deficit during exercise testing in heart failure. Relation to submaximal exercise tolerance.

Measurements of oxygen deficit during submaximal exercise were correlated with the anaerobic threshold (as measured by gas exchange analysis), peak work rate on a ramp protocol, and the ability to perform constant work rate exercise in 10 male patients with New York Heart Association class 2 congestive heart failure and 12 age- and gender-matched normal controls. All subjects performed a maximal ramp exercise test for measurement of the anaerobic threshold. In addition, several 15-min constant work rate exercise sessions were conducted to evaluate oxygen deficit, measured as the area between the "ideal" square curve of oxygen consumption at the onset of constant work rate exercise and the actual exponentially shaped curve. Since the oxygen deficit significantly correlated with the plateau oxygen consumption during the 25-W constant work rate exercise (r = 0.61, p = 0.002), the oxygen deficit was normalized by the rectangular area of 15-min oxygen consumption above baseline. This normalized value significantly correlated with the inverse of the anaerobic threshold (r = 0.81, p < 0.0001). The logarithm of the normalized oxygen deficit significantly correlated with the maximum ramp work rate (r = -0.86, p < 0.0001) and the highest constant work rate sustained for 15 min (r = -0.82, p < 0.0001). In addition, the time to reach plateau oxygen consumption for the 25-W exercise significantly correlated with the inverse of the anaerobic threshold (r = -0.78, p < 0.0001), the maximum ramp work rate (r = -0.76, p < 0.0001), and the highest constant work rate sustained for 15 min (r = -0.74, p < 0.0001). Thus, the oxygen deficit seen in patients with heart failure during constant work rate exercise results from abnormally slow oxygen uptake kinetics and correlates with exercise capacity as measured by anaerobic threshold (via gas exchange analysis) and maximal and submaximal exercise tolerance. Oxygen deficit warrants further evaluation as a submaximal index of functional capacity in patients with heart failure.

Adult↗

PubMed2005

Exercise outcomes after pulmonary rehabilitation depend on the initial mechanism of exercise limitation among non-oxygen-dependent COPD patients.

STUDY OBJECTIVES: Pulmonary rehabilitation (PR) that includes exercise training can improve exercise tolerance and quality of life for patients with COPD. However, the degree of benefit from PR is variable. We hypothesized that the exercise response to PR varies depending on the initial factors that limit exercise. DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS: We retrospectively analyzed the change in exercise capacity after PR in 290 nonhypoxemic patients with COPD. We classified patients into the following subgroups based on the primary limitation seen on initial exercise testing: (1) ventilatory-limited (VL); (2) cardiovascular-limited (CVL); (3) mixed ventilatory/cardiovascular-limited (VLCVL); and (4) non-cardiopulmonary-limited (NL). We compared outcomes among subgroups. RESULTS: In the entire study population, PR led to increased timed walk distance (30.3%; p < 0.0001) and maximal oxygen consumption (VO2max) [84.8 mL/min; p < 0.0001]. Stepwise multiple regression selected age, ventilatory reserve at peak exercise, and exercise arterial oxygen pressure as individual predictors of improvement in VO2max. VO2max increased in the VL subgroup (30.4 mL/min; p = 0.008), the CVL subgroup (109.0 mL/min; p < 0.0001), the mixed VLCVL subgroup (61.3 mL/min; p < 0.0001), and NL subgroups (110.5 L/min; p < 0.0001). The improvement in VO2max was greater in the CVL subgroup than in the VL subgroup (p < 0.0001). Timed walk distance improved to a similar degree in all subgroups (26 to 36%). CONCLUSIONS: Patients with nonventilatory exercise limitations experience the greatest increase in VO2max after PR. However, even patients with severe ventilatory limitation can improve exercise tolerance with PR.

Aged↗

PubMed2003

Relations between perceptual and physiological response during incremental exercise followed by an extended bout of submaximal exercise on a cycle ergometer.

The purpose of this study was to examine the relations of ratings of perceived exertion (RPE) of the legs, chest, and overall body with physiological responses (heart rate and oxygen uptake) both during incremental cycling exercise and the recovery stage (submaximal light exercise after total exhaustion). Subjects were 10 healthy university males ages 18 to 23 years (M age=20.5 yr., SD=1.4 yr.) who performed incremental cycling exercise until exhaustion after 1-min. rest and unloaded cycling for 2 min. They then continued to exercise at a constant load of 30 Watts (used for cooling down; recovery stage) for a total of 25 min. Oxygen uptake and heart rate were measured, and three types of RPE were done; Respiratory (chest; RPE-R), Peripheral (legs; RPE-P), and Overall (overall body; RPE-O) during the exercise and recovery stage. All variables during exercise and RPE-R and RPE-P during recovery stage showed significant linear changes. RPE-O and physiological exercise intensity (oxygen uptake and heart rate) in the recovery stage showed significant curvilinear changes (quadratic). RPE-P were significantly higher than RPE-R both during exercise and the recovery stage and the variables highly correlated (r > or = .88, p < .05). At the point of exhaustion, RPE-P and RPE-O almost reached a peak, but RPE-R did not. In the exercise period until exhaustion, the regression coefficient of RPE-R (.38) was significantly lower than that of RPE-P (.56) and RPE-O (.50), and RPE-R increased according to an increase of the incremental load, but the amount was significantly lower than those of RPE-P and RPE-O. In the recovery stage after exhaustion, the regression coefficient of RPE-O (-1.35) was significantly greater than that of RPE-P (-1.07). A decrease in RPE-O corresponded to a decrease in heart rate and oxygen uptake, but RPE-P did not, and the recovery of RPE-P tended to be late. The results suggest that relations for the physiological responses of heart rate, oxygen uptake, and RPE, and between each RPE in the recovery stage differed from those during exercise until exhaustion.

Adult↗

PubMed2005

[Clinical significance of exercise-induced ST-segment elevation in lead aVR and V1 in patients with chronic stable angina pectoris and strongly positive exercise test results].

Electrocardiographic abnormalities in lead aVR and V1 are rarely analyzed on exercise electrocardiograms. Clinical significance of exercise-induced ST-segment changes in lead aVR and V1 during strongly positive electrocardiographic exercise test (EET) in patients with chronic stable angina pectoris remains unclear. The aim of the study was to assess the value of lead aVR and V1 on the exercise electrocardiogram for the detection of left main coronary artery stenosis (LMCAS) and its equivalent (LMCASE) in patients with chronic stable angina pectoris and the strongly positive EET result. The study group consisted of 118 consecutive patients (mean age 58.8 +/- 9.5 years, range 38-77 years), including 30 (25.4%) women. Patients were divided into three groups. In group I, 31 patients with ST elevation in lead aVR and V1, in group II 66 patients with isolated ST elevation in lead aVR, and in group III 21 patients without ST elevation in lead aVR, induced with exercise, were included. Coronary arteriography results were compared among these groups. In patients with isolated exercise-induced ST elevation in lead aVR, the prevalence of LMCAS was five times more frequent than in patients without lead aVR ST elevation (25.8% vs 4.8% p<0.05). There were no differences in the prevalence of LMCASE and multi-vessel coronary disease in the studied groups. In patients with LMCAS significant ST elevation in lead aVR during strongly positive EET were observed (0.25 +/- 0,4 mm vs 1.43 +/- 0.6 mm p = 0.003), whereas there were no significant exercise-induced electrocardiographic changes in lead V1 (0.61 +/- 0.6 mm vs 0.77 +/- 0.6 mm p = 0.08). Sensitivity of isolated exercise-induced ST elevation in lead aVR in detection of LMCAS was 85.0%, specificity - 50.0%, positive predictive value - 25.8%, negative predictive value - 94.2%, and total accuracy - 55.9%. Exercise-induced ST elevation in lead aVR on the strongly positive exercise ECG may detect LMCAS in patients with chronic stable angina pectoris.

Adult↗

PubMed1993

[The prescription of physical exercise in the individual with aortic prostheses. The role of Doppler exercise study].

BACKGROUND AND OBJECTIVES: Exercise Doppler echocardiography allows measure valvular gradient during exercise, that could be useful in the prescription of physical activity in patients with a prosthetic aortic valve. METHODS: Exercise Doppler echocardiography was performed in 50 patients (mean age 53 +/- 12 years) with normally-functioning aortic prosthesis. Maximal exercise was performed by supine bicycle ergometry in 35 and modified Bruce protocol in 15. Continuous wave Doppler examinations were obtained at rest, during and at maximal exercise with a nonimaging transducer. RESULTS: The mean value of workload was 6.9 +/- 2 METS and there were no complications. Gradients at peak exercise were available in 43/50 patients. Exercise induced a statistic significant increase in the heart rate (76 +/- 14 to 136 +/- 26), systolic blood pressure (128 +/- 19 to 182 +/- 19 mmHg), peak gradient (29 +/- 9 to 61 +/- 17 mmHg) and mean gradient (16 +/- 5 to 32 +/- 9 mmHg). The gradient was greater than 59 mmHg in 18/43 patients, greater than 69 mmHg in 12/43 and greater than 79 mmHg in 5/43. CONCLUSIONS: Prescription of exercise in patients with aortic prosthesis requires perform an exercise Doppler echocardiography to measure the increase of valvular gradient with the exercise in each patient, since the stress testing could be normal, it can advise a rate of physical activity that determine very high prosthetic gradients.

Adult↗

PubMed1997

[Associations between breathing pattern during submaximal exercise and exercise capacity in patients with pulmonary emphysema].

We sought to clarify the factors associated with exercise capacity in patients with pulmonary emphysema. Exercise capacities of 20 men with pulmonary emphysema were evaluated by bicycle ergometery, and the results were used to divide the subjects into two groups: high exercise capacity (n = 10) and low exercise capacity (n = 10). Pulmonary-function tests were done, emphysema scores were computed from CT scans, breathing pattern was recorded during submaximal exercise (up to 20 watts), and index of rapid shallow breathing was computed. Neither FEV1 nor airway resistance differed between the two groups, and patients with lower exercise capacity tended to have lower tidal volumes and higher values of the index of rapid shallow breathing during submaximal exercise. Functional residual capacity measured by body plethysmography and emphysema scores were inversely associated with exercise capacity. We speculate that among patients with pulmonary emphysema and a given degree of airway obstruction, a high functional residual capacity causes breathing during submaxinal exercise to be rapid and shallow, and that this rapid and shallow breathing makes ventilation inefficient, increases the work of breathing, and limits exercise capacity.

Aged↗

PubMed2003

Effects of a 16-month randomized controlled exercise trial on body weight and composition in young, overweight men and women: the Midwest Exercise Trial.

BACKGROUND: In light of the current obesity epidemic, treatment models are needed that can prevent weight gain or provide weight loss. We examined the long-term effects of a supervised program of moderate-intensity exercise on body weight and composition in previously sedentary, overweight and moderately obese men and women. We hypothesized that a 16-month program of verified exercise would prevent weight gain or provide weight loss in the exercise group compared with controls. METHODS: This was a randomized controlled efficacy trial. Participants were recruited from 2 midwestern universities and their surrounding communities. One hundred thirty-one participants were randomized to exercise or control groups, and 74 completed the intervention and all laboratory testing. Exercise was supervised, and the level of energy expenditure of exercise was measured. Controls remained sedentary. All participants maintained ad libitum diets. RESULTS: Exercise prevented weight gain in women and produced weight loss in men. Men in the exercise group had significant mean +/- SD decreases in weight (5.2 +/- 4.7 kg), body mass index (calculated as weight in kilograms divided by the square of height in meters) (1.6 +/- 1.4), and fat mass (4.9 +/- 4.4 kg) compared with controls. Women in the exercise group maintained baseline weight, body mass index, and fat mass, and controls showed significant mean +/- SD increases in body mass index (1.1 +/- 2.0), weight (2.9 +/- 5.5 kg), and fat mass (2.1 +/- 4.8 kg) at 16 months. No significant changes occurred in fat-free mass in either men or women; however, both had significantly reduced visceral fat. CONCLUSIONS: Moderate-intensity exercise sustained for 16 months is effective for weight management in young adults.

Abdomen↗

PubMed1997

Effect of moderate exercise on insulin sensitivity and substrate metabolism during post-exercise recovery in cirrhosis.

We examined whether a single bout of moderate exercise has a beneficial effect on insulin sensitivity and fuel homeostasis in cirrhosis. Clinically stable cirrhotic patients and age-, sex-, and weight-matched controls participated in insulin clamp studies (either euglycemic hyperinsulinemic or hyperglycemic hyperinsulinemic) in combination with indirect calorimetry and [6,6-2H2]glucose. Three to seven days later, studies were repeated following a single bout of exercise (30 minutes of treadmill exercise at 60% of maximal aerobic capacity). After an overnight fast, following exercise, both cirrhotic and control individuals showed a shift in fuel utilization to enhanced lipid oxidation, decreased glucose oxidation, and increased nonoxidative glucose disposal rates (i.e., glycogen synthesis in muscle) when compared with pre-exercise rates but differences were statistically significant only in the patient group. During euglycemic hyperinsulinemia, insulin-mediated glucose disposal was significantly reduced in cirrhotic patients (3.43 +/- 0.26 vs. 7.36 +/- 0.48 mg/kg/min, P < .01). Following exercise, glucose uptake increased significantly in cirrhotic patients when compared with pre-exercise levels (P < .05) but remained unchanged in the control group. The increase in total body glucose disposal in cirrhotic patients was entirely accounted for by an increase in nonoxidative glucose disposal (0.81 +/- 0.20 vs. 0.51 +/- 0.15 mg/kg/min, P < .05). During combined hyperglycemia/hyperinsulinemia, however, insulin sensitivity was unaffected by exercise in both patients and control individuals. In summary, in cirrhotic patients, a single bout of moderate exercise 1) causes a shift in substrate utilization with an increase in lipid oxidation in the postexercise period that is significantly more pronounced than in controls, and 2) increases insulin sensitivity only during euglycemia but not during the more physiological condition of hyperglycemia. Single bouts of moderate exercise therefore may not have a beneficial effect on the metabolic status of patients with chronic liver disease.

Adult↗