No abstract

Background-The effects of diet and diet plus exercise training on muscle vasodilatation during physiological maneuvers in obese children are unknown. We tested the hypothesis that (1) blood pressure (BP) and forearm vascular conductance (FVC) responses during handgrip exercise and mental stress would be altered in obese children and (2) diet plus exercise training would restore BP and FVC responses during exercise and mental stress in obese children. Methods and Results-Thirty-nine obese children (aged 10Ϯ0.2 years) were randomly divided into 2 groups: diet plus exercise training (nϭ21; body mass index [BMI]ϭ28Ϯ0.5 kg/m 2 ) and diet (nϭ18; BMIϭ30Ϯ0.4 kg/m 2 ). Ten age-matched lean control children (BMIϭ17Ϯ0.5 kg/m 2 ) were also studied. Forearm blood flow was measured by venous occlusion plethysmography. BP was monitored noninvasively. Handgrip exercise was performed at 30% maximal voluntary contraction for 3 minutes. Stroop color word test was performed for 4 minutes. Baseline BP was significantly higher and FVC was significantly lower in obese children. During exercise and mental stress, BP responses were significantly higher and FVC responses were significantly lower in obese children. Diet and diet plus exercise training significantly reduced body weight. Diet and diet plus exercise training significantly decreased BP levels during exercise and mental stress. Diet plus exercise training, in contrast to diet alone, significantly increased FVC responses during exercise

Background: Evidence suggests that carvedilol decreases muscle sympathetic nerve activity (MSNA) in patients with heart failure (HF) but carvedilol fails to improve forearm vascular resistance and overall functional capacity. Exercise training in HF reduces MSNA and improves forearm vascular resistance and functional capacity. Aims: To investigate whether the beneficial effects exercise training on MSNA are maintained in the presence of carvedilol. Methods and results: Twenty seven HF patients, NYHA Class II-III, EF b 35%, peak VO 2 b20 ml/kg/min, treated with carvedilol were randomly divided into two groups: exercise training (n = 15) and untrained (n = 12). MSNA was recorded by microneurography. Forearm blood flow (FBF) was measured by venous occlusion plethysmography. The four-month training program consisted of three 60-min exercise/ week on a cycloergometer. Baseline parameters were similar between groups. Exercise training reduced MSNA (− 14 ± 3.3 bursts / 100 HB, p = 0.001) and increased forearm blood flow (0.6 ± 0.1 mL/min/100 g, p b 0.001) in HF patients on carvedilol. In addition, exercise training improved peak VO 2 in HF patients (20 ± 6%, p = 0.002). MSNA, FBF and peak VO 2 were unchanged in untrained HF patients on carvedilol. Conclusion: Exercise training reduces MSNA in heart failure patients treated with carvedilol. In addition, the beneficial effects of exercise training on muscle blood flow and functional capacity are still realized in patients on carvedilol.

The purpose of this study was to test the hypothesis that in obese children: 1) Ventilatory efficiency (VentE) is decreased during graded exercise; and 2) Weight loss through diet alone (D) improves VentE, and 3) diet associated with exercise training (DET) leads to greater improvement in VentE than by D. Thirty-eight obese children (10+/-0.2 years; BMI >95th percentile) were randomly divided into two study groups: D (n=17; BMI=30+/-1 kg/m (2)) and DET (n=21; 28+/-1 kg/m (2)). Ten lean children were included in a control group (10+/-0.3 years; 17+/-0.5 kg/m (2)). All children performed maximal treadmill testing with respiratory gas analysis (breath-by-breath) to determine the ventilatory anaerobic threshold (VAT) and peak oxygen consumption (VO (2) peak). VentE was determined by the VE/VCO (2) method at VAT. Obese children showed lower VO (2) peak and lower VentE than controls (p<0.05). After interventions, all obese children reduced body weight (p<0.05). D group did not improve in terms of VO (2) peak or VentE (p>0.05). In contrast, the DET group showed increased VO (2) peak (p=0.01) and improved VentE (DeltaVE/VCO (2)=-6.1+/-0.9; p=0.01). VentE is decreased in obese children, where weight loss by means of DET, but not D alone, improves VentE and cardiorespiratory fitness during graded exercise.

The purpose of this study was to test the hypotheses that in obese children: 1) hypocaloric diet (D) improves both heart rate recovery at 1 min (Δ HRR1) cfter an exercise test, and cardiac autonomic nervous system activity (CANSA) in obese children; 2) Diet and exercise training (DET) combined leads to greater improvement in both Δ HRR1 after an exercise test and in CANSA, than D alone. Moreover, we examined the relationships among Δ HRR1, CANSA, cardiorespiratory fitness and anthropometric variables (AV) in obese children submitted to D and to DET. 33 obese children (10 ± 0.2 years; body mass index (BMI) >95 (th) percentile) were divided into 2 groups: D (n=15; BMI=31 ± 1 kg/m²)) and DET (n=18; 29 ± 1 kg/m²). All children performed a maximal cardiopulmonary exercise test on a treadmill. The Δ HRR1 or LF/HF ratio (P>0.05). In contrast, the DET group showed increased peak VO₂ ( P=0.01) and improved Δ HRR1 (Δ HRR1=37.3 ± 2.6; P=0.01) and LF/HF ratio ( P=0.001). The DET group demonstrated significant relationships among Δ HRR1, peak VO₂ and CANSA (P<0.05). In conclusion, DET, in contrast to D, promoted improved ÄΔ HRR1 and CANSA in obese children, suggesting a positive influence of increased levels of cardiorespiratory fitness by exercise training on cardiac autonomic activity.