Significant Exercise-induced Increase Research Articles

Hemodynamic Mechanisms of Exercise-Induced Pulmonary Hypertension in Patients with Lymphangioleiomyomatosis: The Role of Exercise Stress Echocardiography

The pathogenesis of pulmonary hypertension (PH) in lymphangioleiomyomatosis (LAM) has not yet been completely clarified. The aim of this study was to conduct a noninvasive evaluation of the main hemodynamic mechanisms of exercise-induced PH in patients with LAM, assessed using exercise stress echocardiography. Fifteen patients with LAM (mean age, 47±13years; all women) without resting PH were enrolled in a prospective single-center study and compared with 15 healthy female control subjects (mean age, 45.2±8years; P=.65). A complete echocardiographic study with Doppler tissue imaging was performed at baseline and during semisupine symptom-limited exercise testing to evaluate (1) left ventricular systolic and diastolic function, (2) right ventricular contractile function, (3) estimated pulmonary capillary wedge pressure, (4) estimated systolic and mean pulmonary artery pressure, and (5) estimated pulmonary vascular resistance. Compared with healthy control subjects, patients with LAM during exercise showed echocardiographic signs of right ventricular overload and right ventricular systolic dysfunction and significant increases in mean pulmonary artery pressure (14.4±6.5 vs 4.2±3.1mm Hg, P<.0001), pulmonary vascular resistance(+68.3±42.1 vs -0.1±18.3 dyne-sec/cm5, P<.0001), and, unexpectedly, pulmonary capillary wedge pressure (+8.3±5.3 vs -0.5±1.3mm Hg, P<.0001). Exercise-induced PH in patients with LAM could be related not only to hypoxic pulmonary vascular vasoconstriction during exercise (precapillary PH) but also to a significant exercise-induced increase in estimated pulmonary capillary wedge pressure, probably secondary to diastolic dysfunction (postcapillary PH).

Effects of cranberry (Vaccinum macrocarpon) supplementation on iron status and inflammatory markers in rowers

BackgroundThe aim of this study was to analyze the effect of supplementation with cranberry (Vaccinum macrocarpon) on the levels of pro-inflammatory cytokines, hepcidin and selected markers of iron metabolism in rowers subjected to exhaustive exercise.MethodsThis double-blind study included 16 members of the Polish Rowing Team. The subjects were randomly assigned to the supplemented group (n = 9), receiving 1200 mg of cranberry extract for 6 weeks, or to the placebo group (n = 7). The participants performed a 2000-m test on a rowing ergometer at the beginning and at the end of the preparatory camp. Blood samples were obtained from the antecubital vein prior to each exercise test, one minute after completing the test, and after a 24-h recovery period. The levels of hepcidin, interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-alpha), ferritin, iron, soluble transferrin receptor (sTfR) and myoglobin were determined, along with total iron-binding capacity (TIBC), unbound iron-binding capacity (UIBC) and total antioxidant capacity (TAC).ResultsBoth prior and after the supplementation, a significant post-exercise increase in the concentration of IL-6 was observed in both groups. At the end of the study period, cranberry-supplemented athletes presented with significantly higher resting, post-exercise and post-recovery levels of TAC than the controls. However, a significant exercise-induced increase in the concentrations of TNF-alpha, myoglobin and hepcidin was observed solely in the control group.ConclusionSupplementation with cranberry extract contributed to a significant strengthening of antioxidant potential in individuals exposed to strenuous physical exercise. However, supplementation did not exert direct effects on other analyzed parameters: inflammatory markers and indices of iron metabolism (TNF-alpha, hepcidin and myoglobin).

Clinical and echocardiographic correlations of exercise-induced pulmonary hypertension in systemic sclerosis: A multicenter study

Patients with systemic sclerosis (SSc) are at risk for developing pulmonary hypertension, which is associated with a poor prognosis. Exercise Doppler echocardiography enables the identification of exercise-induced increase in pulmonary artery systolic pressure (PASP) and may provide a thorough noninvasive hemodynamic evaluation. The aim of this study was to evaluate the clinical and echocardiographic determinants of exercise-induced increase in PASP in a large population of patients with SSc. We selected 164 patients with SSc (age 58 ± 13 years, 91% female) with normal resting PASP (<40 mm Hg) who underwent a comprehensive 2-dimensional and Doppler echocardiography and graded bicycle semisupine exercise Doppler echocardiography. Pulmonary artery systolic pressure, cardiac output, and pulmonary vascular resistance (PVR) were estimated noninvasively. Cutoff values of PASP ≥50 mm Hg and PVR ≥3.0 Wood Units at peak exercise were considered a significant exercise-induced increase in PASP and PVR, respectively. Sixty-nine (42%) patients showed a significant exercise-induced increase in PASP. Among them, peak PVR ≥3 Wood Units was present only in 11% of patients, about 5% of the total population. Univariate analysis showed that age, presence of interstitial lung disease, and both right and left diastolic dysfunction are predictors of peak PASP ≥50 mm Hg, but none of these parameters predict elevated peak PVR. Exercise-induced increase in PASP occurs in almost one-half of patients with SSc with normal resting PASP. Peak exercise PASP is affected by age, interstitial lung disease, and right and left ventricular diastolic dysfunction and, only in 5% of the patients, is associated with an increase in PVR during exercise, suggesting heterogeneity of the mechanisms underlying exercise-induced pulmonary hypertension in SSc.

Lipid-peroxidation and peroxiredoxin-overoxidation in the erythrocytes of non-insulin-dependent type 2 diabetic men during acute exercise

Single bouts of exercise induce an acute state of oxidative stress. It is largely unknown what this means in the context of diseases which are associated with increased oxidative stress, e.g., type 2 diabetes mellitus (T2DM). Free radicals can destroy the structure of erythrocytes and reduce their deformability. Antioxidative peroxiredoxins are highly abundant in erythrocytes. Therefore, we immunohistochemically examined whether the free radical-induced erythrocyte lipid-peroxidation measured by 8-iso-prostaglandin-F2α (8-Iso-PGF) as well as the erythrocyte contents of overoxidized peroxiredoxins (PRDX-SO(2-3)) differ between overweight/obese T2DM men (n = 15, years = 59 ± 10 (mean ± SD)) and overweight/obese non-diabetic control subjects (n = 12, years = 53 ± 4) during acute exercise (WHO-step test). We further studied whether physical training affects the oxidative stress response to acute exercise. Seven men belonging to the diabetic group took part in a moderate intensity cycling endurance training. Erythrocyte 8-Iso-PGF significantly increased during acute exercise and decreased in the 30-min recovery phase in untrained diabetic and non-diabetic men (P ≤ 0.05). Increases/decreases in 8-Iso-PGF in relation to exercise/recovery time were similar in both groups. A significant exercise-induced increase in the contents of erythrocyte PRDX-SO(2-3) was only observed in T2DM men (P ≤ 0.05). PRDX-SO(2-3) contents were not reduced during recovery. Following physical training, the magnitude of exercise-induced increases in 8-Iso-PGF (relative to exercise time) was significantly lower in the erythrocytes of T2DM men (P ≤ 0.05), whereas increases in PRDX-SO(2-3) were significantly higher (P ≤ 0.05). Exercise-induced erythrocyte lipid-peroxidation is similar in untrained overweight/obese T2DM patients and overweight/obese control subjects, while antioxidative mechanisms differ. Physical training might improve oxidative stress in T2DM men's erythrocytes during acute exercise.

164 Degenerative Mitral Regurgitation Severity Changes During Exercise Echocardiography

Recent studies revealed that mitral regurgitation (MR) severity may change during exercise in patients with functional MR. Significant exercise-induced increases in MR is associated with poor outcome. By contrast, changes in MR severity during exercise remain undetermined in patients with degenerative MR. Resting and symptom-limited semi-supine bicycle exercise Doppler-echocardiography were performed in 66 consecutive patients (61±15 yrs and 55% of male) with moderate to severe degenerative MR. MR severity was evaluated, at rest and during exercise using effective regurgitant orifice (ERO) calculated with the PISA (ERO P ) and the quantitative Doppler (ERO D ) methods. Systolic pulmonary arterial pressure (PAP) was derived from the peak regurgitant tricuspid pressure gradient. At rest, ERO D was greater than ERO P (52±16mm 2 vs. 31±17mm 2 , p<0.01) and were well correlated (r=0.65, p=0.004). During exercise, ERO P and ERO D increase in 71%, 54% and 54% of patients, respectively and there were good correlations between exercise ERO P and ERO D (r=0.73, p<0.01). Systolic PAP also increased during exercise (from 29±9 to 52±16mmHg, p<0.01) and changes in PAP during test were correlated with changes in ERO P and ERO D (r=0.33, p=0.04 and r=0.44, p=0.004). Moreover, patients with exercise peak PAP>60mmHg had higher exercise ERO P (33±21mm 2 vs. 45±22mm 2 , p=0.04) and ERO D (49±20 vs. 69±27mm 2 , p=0.005) and higher exercise-induced change in in ERO D (-2.7±17 vs. 12±18 mm 2 , p=0.006). After adjustment for age, sex and resting PAP, exercise-induced changes in ERO D remained associated with changes in PAP (β=0.22, p=0.033) As in functional MR, degenerative MR can be dynamic and increases during exercise in >50% of patients. Changes in MR severity are associated with exerciseinduced changes in systolic PAP, suggesting a potential impact on outcome. Further studies are needed to determine whether exercise-induced increase in MR has prognostic importance.

Pathogenesis of Age-Related Osteoporosis: Impaired Mechano-Responsiveness of Bone Is Not the Culprit

BackgroundAccording to prevailing understanding, skeletal mechano-responsiveness declines with age and this apparent failure of the mechano-sensory feedback system has been attributed to the gradual bone loss with aging (age-related osteoporosis). The objective of this study was to evaluate whether the capacity of senescent skeleton to respond to increased loading is indeed reduced as compared to young mature skeleton.Methods and Findings108 male and 101 female rats were randomly assigned into Exercise and Control groups. Exercise groups were subjected to treadmill training either at peak bone mass between 47–61 weeks of age (Mature) or at senescence between 75–102 weeks of age (Senescent). After the training intervention, femoral necks and diaphysis were evaluated with peripheral quantitative computed tomography (pQCT) and mechanical testing; the proximal tibia was assessed with microcomputed tomography (μCT). The μCT analysis revealed that the senescent bone tissue was structurally deteriorated compared to the mature bone tissue, confirming the existence of age-related osteoporosis. As regards the mechano-responsiveness, the used loading resulted in only marginal increases in the bones of the mature animals, while significant exercise-induced increases were observed virtually in all bone traits among the senescent rats.ConclusionThe bones of senescent rats displayed a clear ability to respond to an exercise regimen that failed to initiate an adaptive response in mature animals. Thus, our observations suggest that the pathogenesis of age-related osteoporosis is not attributable to impaired mechano-responsiveness of aging skeleton. It also seems that strengthening of even senescent bones is possible – naturally provided that safe and efficient training methods can be developed for the oldest old.

Biventricular pacing: Impact on exercise-induced increases in mitral insufficiency in patients with chronic heart failure

Mitral regurgitation (MR) in chronic heart failure (CHF) patients frequently worsens with exercise. Cardiac resynchronization therapy (CRT) reduces MR at rest, but its effects on exercise-induced worsening of MR are incompletely explored. The present study examined the influence of CRT on MR during submaximal exercise in CHF patients. Eleven patients with CHF who were treated with CRT underwent echocardiography while performing steady-state exercise during four conduction modes (intrinsic rhythm, right ventricular [RV], biventricular [BiV] and left ventricular [LV] pacing). Measurements of MR were jet area planimetry, effective regurgitant orifice area, peak MR flow rate and regurgitant volume. At rest and during exercise, there were no differences in dyssynchrony between intrinsic rhythm and RV pacing. BiV and LV pacing reduced dyssynchrony at rest and during exercise compared with intrinsic conduction and RV pacing, and there were no differences in the magnitude of these effects between these two pacing modes. At rest, RV pacing increased MR compared with intrinsic conduction (MR regurgitant volume; P<0.05), whereas BiV and LV pacing reduced MR (reductions in effective regurgitant orifice area and jet area; P<0.02, and MR flow rate; P<0.05 with BiV pacing from intrinsic conduction). MR significantly increased on exercise with intrinsic rhythm and RV pacing, whereas with LV and BiV pacing, there were no significant exercise-induced increases in any MR variable. There were relationships between changes in measures of dyssynchrony and reductions in MR at rest and during exercise. CRT reduces MR at rest and during exercise, and prevents exercise-induced MR. Reductions in MR during exercise correlate with improvements in dyssynchrony.

The effects of body-weight supported treadmill training on cardiovascular regulation in individuals with motor-complete SCI

Four-month longitudinal within-subject exercise training study. Although body-weight supported treadmill training (BWSTT) has not shown promise as a means of improving ambulation in individuals with motor-complete spinal cord injury (SCI), it may still improve cardiovascular health and function in this population. The purpose of this study was to (i) investigate the effects of BWSTT on peripheral muscular and elastic artery dimension and function and measures of heart rate variability (HRV) and blood pressure variability (BPV) in individuals with motor-complete SCI, and (ii) to make a preliminary examination of what factors may predict favourable cardiovascular outcomes following BWSTT in this population. Centre for Health Promotion and Rehabilitation, McMaster University, Hamilton, Ontario, Canada. Six individuals (four male, two female; age 37.7+/-15.4 years) with chronic SCI (C4-T12; ASIA A-B; 7.6+/-9.4 years post-injury) were included in the present investigation. Doppler ultrasound was used to determine femoral (exercising; muscular), carotid (elastic) and brachial (non-exercising control; muscular) artery dimension and function before and after 4 months of BWSTT. Continuous heart rate and blood pressure were also recorded before and after 4-months of BWSTT to determine frequency domain measures of HRV and BPV; clinically valuable indices of neurocardiac and neurovascular control, respectively. Two-way ANOVA (vessel x time) revealed no exercise-induced change in femoral or carotid artery cross-sectional area, blood flow or resistance and no change in carotid artery compliance following the 4 months of BWSTT compared to the non-exercising control brachial artery. However, there was a significant exercise-induced increase in femoral artery compliance. There were no exercise-induced changes in HRV or BPV when all participants were considered together. However, the results suggest that the subgroup of individuals who had a substantial heart rate response to BWSTT (n=3), experienced exercise-training induced changes in HRV reflective of a relative shift toward cardiac vagal predominance and reductions in BPV. BWSTT may cause an increase in femoral artery compliance in individuals with motor-complete SCI and therefore, should be encouraged as a means of improving cardiovascular health in this population. BWSTT may also cause modest improvements in measures of HRV and BPV in a select subgroup of individuals who respond to ambulation with moderate to large increases in HR. In the present study, factors associated with a substantial HR response to BWSTT were a propensity to orthostatic intolerance and muscular spasticity.

Dynamic changes of QT dispersion as a predictor of myocardial ischemia on exercise testing in patients with angina pectoris.

The difference between the maximum and minimum QT intervals on the standard 12-lead ECG (QT dispersion) may be a significant predictor of serious arrhythmias. Dynamic changes in QTd were determined during exercise-induced ischemia in 15 patients with effort angina (> or = 75% coronary stenosis) and 10 normal individuals. Treadmill exercise testing was performed according to Bruce's protocol and the rate-corrected QT dispersion (QTcd) was calculated using Bazett's formula. The resting QTcd before exercise was similar in the angina patients and the controls. After the first stage of exercise, QTcd was significantly increased in the angina patients (p = 0.035), while it remained near baseline in the controls. Five minutes after completing exercise, QTcd was significantly greater in the angina patients than in the controls (p = 0.011). Furthermore, QTcd values after the first stage of exercise were significantly correlated with the maximum ST depression observed on completing exercise in the angina patients (r = 0.714, p = 0.0028). Because QTd may represent the heterogeneity of ventricular repolarization, its significant exercise-induced increase in the angina patients suggests that myocardial ischemia caused repolarization disorders. The significant correlation between QTcd values after the first stage of exercise (before significant ST depression) and the maximum ST depression on completing exercise suggests that an increase in QTcd preceding ischemic ST depression may predict myocardial ischemia. In addition, even daily activities not causing significant ST changes may increase QTcd and the risk of serious arrhythmia in angina patients.

A period of anaerobic exercise increases the accumulation of reactive carbonyl derivatives in the lungs of rats.

It is known that acute physical exercise may have diverse pathophysiological consequences in various organs due to free radical formation. We have investigated whether a period of anaerobic running to exhaustion in rats results in oxidative modification of proteins in the lungs. Six rats of an exercised group (E) ran for two periods of 5 min at a speed of 30 m.min-1 followed by a recovery period of 5 min, and then by a third period of running to exhaustion. Reactive carbonyl derivatives (RCD) were measured by the Western blot technique on lungs of E and control (C) rats. In addition, the activity of glutamine synthetase (GS) was also monitored as marker of oxidative damage to proteins. This investigation revealed significant exercise-induced increases in accumulation of RCD in the lungs of the E group compared with the C group. The RCD signals were visibly stronger in proteins with molecular weight of 55 kDa and 32 kDa. The activity of GS was higher by about 30% in E rats than in C rats. The present data suggest that anaerobic exercise induces protein oxidation in the lungs.

Exercise Doppler echocardiography in conjunction with right heart catheterization for the assessment of mitral stenosis.

A new diagnostic approach is reported, which combines Doppler echocardiography and a thermodilution technique for the calculation of mitral valve area at rest and during exercise. This method was applied to determine the magnitude of mitral valve reserve (= exercise-induced increase of mitral valve are) and to assess the hemodynamic relevance of mitral stenosis. 69 patients with mitral stenosis were included in this study. A Swan-Ganz catheter was used to measure exercise hemodynamics and transvalvular flow by a thermodilution technique. The mean transmitral flow velocity vmean was determined by continuous wave Doppler. Measurements were performed simultaneously at rest and during stepwise bicycle ergometry. Effective mitral valve area was calculated according to the continuity equation method (MVACE = Flow/vmean). A significant exercise-induced increase of mitral valve area was found in the total group (rest-->25 W: 1.1 +/- 0.3-->1.3 +/- 0.4 cm2, p < 0.001). Two subgroups were defined according to the presence or absence of mitral valve reserve: delta MVA > and = 20%: group A (n = 30); delta MVA < 20%: group B (n = 39). Both groups did not differ with regard to mitral valve area at rest. However, the increase of cardiac output and stroke volume was significantly higher in group A than in group B. An effective mitral valve area at 25 W of less than 1.2 cm2 had an 80% sensitivity and an 83% specificity to detect a severe mitral stenosis. Because the presence and extent of mitral valve reserve cannot be predicted under resting conditions measurements under flow-increasing interventions are necessary. Our data demonstrate that exercise Doppler in conjunction with right-sided cardiac catheterization is most useful to determine mitral valve reserve and to assess the hemodynamic relevance of mitral stenosis.

Acute hormonal responses in elite junior weightlifters.

To date, no published studies have demonstrated resistance exercise-induced increases in serum testosterone in adolescent males. Furthermore, few data are available on the effects of training experience and lifting performance on acute hormonal responses to weightlifting in young males. Twenty-eight junior elite male Olympic-style weightlifters (17.3 +/- 1.4 yrs) volunteered for the study. An acute weightlifting exercise protocol using moderate to high intensity loads and low volume, characteristic of many weightlifting training sessions, was examined. The exercise protocol was directed toward the training associated with the snatch lift weightlifting exercise. Blood samples were obtained from a superficial arm vein at 7 a.m. (for baseline measurements), and again at pre-exercise, 5 min post-, and 15 min post-exercise time points for determination of serum testosterone, cortisol, growth hormone, plasma beta-endorphin, and whole blood lactate. The exercise protocol elicited significant (p less than or equal to 0.05) increases in each of the hormones and whole blood lactate compared to pre-exercise measures. While not being significantly older, subsequent analysis revealed that subjects with greater than 2 years training experience exhibited significant exercise-induced increases in serum testosterone from pre-exercise to 5 min post-exercise (16.2 +/- 6.2 to 21.4 +/- 7.9 nmol.l-1), while those with less than or equal to 2 years training showed no significant serum testosterone differences. None of the other hormones or whole blood lactate appear to be influenced by training experience.(ABSTRACT TRUNCATED AT 250 WORDS)

Training responses of plasma beta-endorphin, adrenocorticotropin, and cortisol

The purpose of this study was to examine the effects of three different run training programs on plasma responses of beta-endorphin (beta-EP), adrenocorticotropin (ACTH), and cortisol to maximal treadmill exercise. Subjects were randomly assigned to one of three training groups: sprint intervals (SI) (N = 8), endurance (E) (N = 10), or combination (C) (N = 7). Training was monitored for 10 wk, and maximal treadmill exercise tests were administered pre-training and after 2, 4, 6, 8, and 10 wk of training. Blood samples were obtained (pre-training and after 10 wk) before, immediately after, and 5 and 15 min following the maximal exercise tests. All groups significantly (P less than 0.05) increased maximal oxygen consumption values at 8 and 10 wk of the training period. Significant exercise-induced increase in plasma beta-EP, ACTH, cortisol, and blood lactate were observed for both pre- and post-training tests in all training groups. The SI group demonstrated significant post-training increases in beta-EP, ACTH, cortisol, and 5 min post-exercise blood lactate concentrations in response to maximal exercise. No training-induced hormonal changes were observed for the E group. While exercise-induced increases were observed, the C group exhibited significant post-training reductions in plasma responses of beta-EP, ACTH, and blood lactate concentrations in response to maximal exercise. Still, resting and post-exercise increases in plasma cortisol concentrations were significantly higher in magnitude in the post-training test. Lactate was significantly correlated with beta-EP (r = 0.72), ACTH (r = 0.70), and cortisol (r = 0.64).(ABSTRACT TRUNCATED AT 250 WORDS)