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Giunta M.,Laboratorio Sperimentale Of Ricerche Auxo Endocrinologiche | Giunta M.,University of Milan | Cardinale M.,University College London | Cardinale M.,University of Aberdeen | And 5 more authors.
Obesity Facts | Year: 2012

Background: Whole body vibration (WBV) has been reported to exert growth hormone(GH)-releasing effects in healthy subjects. Despite the potential of WBV to positively affect body composition changes via lipolytic effects, few studies have been performed in obese subjects to date. Methods: This study evaluated the acute effects of WBV alone or in combination with squatting plus external load (WBV+S) on serum GH levels and blood lactate concentrations in 7 severely obese women (age 22 ± 5 years; BMI 39.9 ± 2.9 kg/m2). Results: WBV and WBV+S determined a significant GH increase (mean GH peaks 5.1 ± 1.9 ng/ml, p < 0.001 vs. basal, and 6.5 ± 3.7 ng/ml, p < 0.001 vs. basal, respectively), GH peaks occurring immediately after both exercise sessions. No significant differences were observed between GH peaks and GH net incremental area under the curve (nAUC) after both conditions (p = 0.39 and p = 0.53, respectively), the whole pattern of GH responsiveness being comparable among all the subjects. Lactate concentrations increased after both conditions (mean lactate peaks 2.0 ± 0.5 mmol/l, p < 0.05 vs. basal, and 4.5 ± 2.0 mmol/l, p < 0.001 vs. basal, respectively). The lactate response was significantly higher after WBV+S than after WBV (p < 0.05). Baseline GH and GH peak values positively correlated to baseline lactate and lactate peak concentrations in both conditions (R2 = 0.64, p < 0.001, and R2 = 0.52, p < 0.05, respectively). Conclusions: WBV alone stimulates GH release and lactate production in severely obese female subjects, with no additive effect when combined with squatting plus external load. Further additional studies are required to verify the chronic effects of WBV exercise on the GH/IGF-1 system, which could represent a potentially effective approach for weight management in obese subjects. Copyright © 2012 S. Karger GmbH, Freiburg. Source

Sartorio A.,Laboratorio Sperimentale Of Ricerche Auxo Endocrinologiche | Lafortuna C.L.,CNR Institute of Molecular Bioimaging and Physiology | Maffiuletti N.A.,Neuromuscular Research Laboratory | Agosti F.,Laboratorio Sperimentale Of Ricerche Auxo Endocrinologiche | And 4 more authors.
Growth Hormone and IGF Research | Year: 2010

Background: Pharmacological or exercise stimuli repeated at a short interval (but not electrical muscle stimulation) are associated with a blunting of GH responsiveness. Aim: To compare GH responses to repeated bout of three different GH-releasing stimuli. Methods: The effects of two consecutive bouts (with a 2-h interval) of whole body vibrations (WBV), maximal voluntary contractions alone (MVC), or alternated with WBV (MVC-WBV) on blood GH and lactate (LA) were assessed in nine young males. Results: Baseline levels of both GH and LA increased significantly after the first bout of all the tested stimuli, and were significantly lower after WBV than after MVC or MVC alternated with WBV, no difference being detected between these last. The administration of a second bout resulted in significantly lower GH increases than those elicited in the first bout in the three different tests; significantly lower LA responses were recorded after the second bout of MVC and MVC-WBV when compared with those obtained after the first bout, while no significant differences were observed after the two WBV bouts for LA. All responses after the second bout of MVC and MVC-WBV were significantly higher than those observed after WBV alone. GH concentrations were significantly correlated with LA after all stimuli, although LA concentrations after the second bout were associated with markedly lower GH levels. Conclusions: A significant blunting of GH responsiveness ensues after a second bout of different GH-releasing stimuli, independent from the amount of GH released after the first bout. This is a pattern also observed for other pharmacological stimuli and exercise modalities, and suggests a common mechanism underlying different GH-releasing stimuli. © 2010 Growth Hormone Research Society. Source

Lazzer S.,Laboratorio Sperimentale Of Ricerche Auxo Endocrinologiche | Lazzer S.,University of Udine | Bedogni G.,Centro Studi Fegato | Lafortuna C.L.,CNR Institute of Molecular Bioimaging and Physiology | And 6 more authors.
Obesity | Year: 2010

The objective of the present study was to explore the relationship between basal metabolic rate (BMR), gender, age, anthropometric characteristics, and body composition in severely obese white subjects. In total, 1,412 obese white children and adolescents (BMI 97° percentile for gender and age) and 7,368 obese adults (BMI 30 kg/m 2) from 7 to 74 years were enrolled in this study. BMR was measured using an indirect calorimeter equipped with a canopy and fat free mass (FFM) were obtained using tetrapolar bioelectrical impedance analysis (BIA). Using analysis of covariance, we tested the effect of gender on the relationship between BMR, age, anthropometry, and body composition. In children and adolescents, the predictor × gender interaction was significant in all cases except for FFM × gender. In adults, all predictor × gender interactions were significant. A prediction equation based on body weight (BW), age, and gender had virtually the same accuracy of the one based on FFM, age, and gender to predict BMR in both children and adults (R 2 adj = 0.59 and 0.60, respectively). In conclusion, gender was a significant determinant of BMR in children and adolescents but not in adults. Our results support the hypothesis that the age-related decline in BMR is due to a reduction in FFM. Finally, anthropometric predictors of BMR are as accurate as body composition estimated by BIA. Source

Lazzer S.,Laboratorio Sperimentale Of Ricerche Auxo Endocrinologiche | Lazzer S.,University of Udine | Lafortuna C.,CNR Institute of Molecular Bioimaging and Physiology | Busti C.,Laboratorio Sperimentale Of Ricerche Auxo Endocrinologiche | And 4 more authors.
European Journal of Applied Physiology | Year: 2010

The objective is to study the effects of low-intensity (LI) or high-intensity (HI) equicaloric exercises on energy expenditure (EE) and substrate oxidation rate during and after the exercises in severely obese Caucasian adolescents. Twenty obese boys (BMI-SDS 3.04 ± 0.52, %Fat Mass 38.2 ± 2.1%) aged 14-16 years (pubertal stage >3) participated in this study. Maximal oxygen uptake (V'O2max) and maximal fat oxidation rate were determined with indirect calorimetry using a graded exercise test on a treadmill. EE and substrate oxidation rate during equicaloric low-intensity (LI, 42% V'O2max for 45 min) and high-intensity (HI, 67% V'O 2max for 30 min) exercises on a treadmill and during post-exercise recovery period (60 min) were determined with indirect calorimetry. Maximal fat oxidation rate was observed at 42 ± 6% V'O2max (62 ± 5% HRmax) and fat oxidation rate was 0.45 ± 0.07 g/min. The total amounts of EE, during the LI and HI exercises, and the post-exercise recovery periods were not significantly different (1,884 ± 250 vs. 1,973 ± 201 kJ, p = 0.453), but the total amount of fat oxidised was significantly higher (+9.9 g, +55.7%, p < 0.001) during the LI exercise than during the HI exercise. However, fat oxidation rates during the post-exercise recovery periods were not significantly different following LI and HI exercises. Total fat oxidised was significantly higher during the LI than during the HI exercise in obese adolescents. However, the equicaloric exercise intensity did not influence EE, fat and carbohydrate oxidation rate during the recovery period. © 2009 Springer-Verlag. Source

Lafortuna C.L.,CNR Institute of Molecular Bioimaging and Physiology | Adorni F.,CNR Institute of Biomedical Technologies | Agosti F.,Laboratorio Sperimentale Of Ricerche Auxo Endocrinologiche | De Col A.,Laboratorio Sperimentale Of Ricerche Auxo Endocrinologiche | And 3 more authors.
Diabetes Research and Clinical Practice | Year: 2010

Juvenile metabolic syndrome (MetS) is a growing major medical problem in industrialised countries. We estimated its prevalence among two similar clinic-based sequentially recruited cohorts of extremely obese adolescents (age: 12-18 years) from Italy (N = 665, males = 271, females = 394) and Germany (N = 661, males = 261, females = 400) using the recent IDF paediatric criteria. The prevalence of the MetS was 23.3% among the Italians and 40.4% among the Germans. A multivariate logistic regression revealed an increased risk related to age (adjusted odd ratio (AOR): 2.24; 95% confidence interval (CI): 1.59-3.16; p < 0.001), BMI SDS (AOR: 3.61; 95% CI: 2.33-5.60; p < 0.001), male gender (AOR: 2.36; 95% CI: 1.80-3.10; p < 0.001), and in German adolescents (AOR: 2.56; 95% CI: 1.98-3.31; p < 0.001). Among Italian adolescents having the MetS, 83% had 3 abnormalities, 16% had 4 abnormalities while less than 1% had all the 5 abnormalities. In the German cohort, 67%, 28% and 5% of affected individuals had 3, 4 and 5 abnormalities, respectively. These results indicate that MetS is highly prevalent among extremely obese adolescents, and suggest that (besides age, obesity and gender) national sociocultural factors, as alimentary trends, could be important. Further tools should be developed to understand international epidemiological differences concerning obesity and its comorbidities in relation to lifestyles in the countries of European Union. © 2010 Elsevier Ireland Ltd. All rights reserved. Source

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