Mauro Lombardo

Dose-response relationship of autonomic nervous system responses to individualized training impulse in marathon runners.

In athletes, exercise training induces autonomic nervous system (ANS) adaptations that could be used to monitor training status. However, the relationship between training and ANS in athletes has been investigated without regard for individual training loads. We tested the hypothesis that in long-distance athletes, changes in ANS parameters are dose-response related to individual volume/intensity training load and could predict athletic performance. A spectral analysis of heart rate (HR), systolic arterial pressure variability, and baroreflex sensitivity by the sequences technique was investigated in eight recreational athletes during a 6-mo training period culminating with a marathon. Individualized training load responses were monitored by a modified training impulse (TRIMP(i)) method, which was determined in each athlete using the individual HR and lactate profiling determined during a treadmill test. Monthly TRIMP(i) steadily increased during the training period. All the ANS parameters were significantly and very highly correlated to the dose of exercise with a second-order regression model (r(2) ranged from 0.90 to 0.99; P < 0.001). Variance, high-frequency oscillations of HR variability (HRV), and baroreflex sensitivity resembled a bell-shaped curve with a minimum at the highest TRIMP(i), whereas low-frequency oscillations of HR and systolic arterial pressure variability and the low frequency (LF)-to-high frequency ratio resembled an U-shaped curve with a maximum at the highest TRIMP(i). The LF component of HRV assessed at the last recording session was significantly and inversely correlated to the time needed to complete the nearing marathon. These results suggest that in recreational athletes, ANS adaptations to exercise training are dose related on an individual basis, showing a progressive shift toward a sympathetic predominance, and that LF oscillations in HRV at peak training load could predict athletic achievement in this athlete population.

Morning Meal More Efficient for Fat Loss in a 3-Month Lifestyle Intervention

Objective: To evaluate the effects of 2 low-calorie diets but with different distributions of calories throughout the day on weight loss and other major obesity-related metabolic parameters. Methods: We randomly assigned 42 nonsmoking homemakers (age = 46.3 ± 2.3 years, body mass index [BMI] = 35.7 ± 0.8 kg/m2, mean ± SD) in 2 groups of 21 subjects (G1 and G2). The participants underwent a 3 month individualized Mediterranean-style diet (55% carbohydrate, 30% fat, 15% protein and fiber > 30 g), calorie (600 kcal daily deficit compared to the total energy expenditure measured by a metabolic Holter). Diets consisted of the same food and complied with cardiovascular disease prevention guidelines but differed in the distribution of calories throughout the day (G1: 70% breakfast, morning snack, lunch and 30% afternoon snack and dinner; G2: 55 breakfast, morning snack, lunch and 45% afternoon snack and dinner). Dual-energy X-ray absorptiometry was used for pre- and postintervention body composition assessment. Results: Thirty-six subjects completed the study (G1 = 18, G2 = 18). Both groups had significant improvements in body composition and metabolic parameters but G1 had enhanced results for weight loss (G1: −8.2 ± 3.0 kg; G2: −6.5 ± 3.4 kg; p = 0.028), waist circumference reduction (G1: −7 ± 0.6 cm; G2: −5 ± 0.3 cm; p = 0.033), and fat mass loss (G1: −6.8 ± 2.1 kg, G2: −4.5 ± 2.9 kg, p = 0.031; mean ± SD). Improvements were detected in both groups for blood pressure and blood and lipid parameters. G1 subjects showed a greater improvement in insulin sensitivity measured by homeostasis model assessment–estimated insulin resistance (G1: −1.37 ± 0.27, G2: −0.74 ± 0.12, p = 0.017). Conclusions: These data suggest that a low-calorie Mediterranean diet with a higher amount of calories in the first part of the day could establish a greater reduction in fat mass and improved insulin sensitivity than a typical daily diet.

Parathyroid Hormone and Insulin Resistance in Distinct Phenotypes of Severe Obesity: A Cross-Sectional Analysis in Middle-Aged Men and Premenopausal Women

CONTEXT High levels of PTH are reported in obese individuals and related to increased cardiometabolic risk. OBJECTIVE Our objective was to evaluate whether the relationship between PTH, insulin resistance, and related metabolic parameters differ between metabolically healthy obese (MHO) and insulin-resistant obese (IRO) subjects. DESIGN AND SETTING We conducted a cross-sectional study among patients evaluated for bariatric surgery in our University Hospital. PATIENTS Patients initially included were 174 severely obese subjects (114 women, aged 40 ± 5 yr, body mass index of 45 ± 6 kg/m(2)) without diabetes, chronic kidney disease, or hyperparathyroidism. MHO (n = 43) and IRO (n = 86) subjects were identified according to quartiles of insulin resistance. MAIN OUTCOME MEASURES Fasting and postload glucose, insulin, total and high-density lipoprotein cholesterol, triglycerides, creatinine, calcium, phosphorus, PTH, 25-hydroxyvitamin D (25OHD), fibrinogen, and high-sensitivity C-reactive protein were assessed. Insulin sensitivity index was derived from a 75-g oral glucose tolerance test. Fat distribution and bone mineral density were assessed with dual-energy x-ray absorptiometry. RESULTS Although 25OHD levels were higher in MHO than in IRO subjects [72.23 (59.41-80.36) vs. 52.36 (41.98-62.57) nmol/liter, P = 0.002], PTH levels were comparable between groups (74.4 ± 13.2 vs. 72.1 ± 15.1 ng/liter, P = 0.34). No differences in serum calcium, phosphorus, bone mineral density, and renal function were detected. An independent inverse association between 25OHD and insulin resistance was seen in both groups. In contrast to IRO subjects, after adjusting for covariates, PTH levels were unrelated to insulin sensitivity index, fasting and postload glucose, insulin, and high-sensitivity C-reactive protein in MHO subjects. CONCLUSIONS MHO and IRO subjects show comparably high levels of circulating PTH, which are not associated with insulin resistance and related metabolic parameters in MHO subjects. Most of the associations observed in IRO subjects appear to be mediated by greater truncal fat mass.

Effects of whole body vibration plus diet on insulin-resistance in middle-aged obese subjects.

We investigated the early effects of whole body vibration (WBV) added to hypocaloric diet on insulin-resistance and other parameters associated with glucose regulation in sedentary obese individuals. We randomly assigned 34 patients to WBV plus hypocaloric diet (WBV group) or diet alone (CON group) for 8 weeks. Fasting and post-load glucose, insulin, lipids, C-reactive protein, tumor necrosis factor-α, leptin, adiponectin were assessed. Insulin sensitivity index (ISI) was derived from oral-glucose-tolerance test. Body composition was evaluated with dual-energy X-ray absorptiometry. Both groups lost approximately 5% of weight, with greater reduction of body fat in WBV than in CON (-7.1±1.2 Kg vs. -5.3±1.0 Kg, p=0.003). Percent variation of ISI was more pronounced in WBV than in CON group (+35±4% vs. + 22±5%, p=0.002), accompanied by slight improvement in post-load glucose (-1.07±0.02 vs. - 0.12±0.01 mmol/l, p=0.031) but without changes in fasting levels. Adiponectin significantly increased in WBV group compared with CON (p=0.021 for comparison) whereas no differences in leptin and inflammatory markers were observed. In middle-aged sedentary obese subjects, WBV added to hypocaloric diet for 8 weeks improved body composition, insulin-resistance, glucose regulation and adiponectin levels to a greater extent compared with diet alone. Efficacy and feasibility of this approach in the long term need to be ascertained.

SGK-1 protects kidney cells against apoptosis induced by ceramide and TNF-α

Ceramide regulates several different cellular responses including mechanisms leading to apoptosis. Serum- and glucocorticoid-inducible protein kinase (SGK)-1 is a serine threonine kinase, which activates survival pathways in response to stress stimuli. Recently, we demonstrated an anti-apoptotic role of SGK-1 in human umbilical endothelial cells treated with high glucose. In the present study, since ceramide induces apoptosis by multiple mechanisms in diabetes and its complication such as nephropathy, we aimed to investigate whether SGK-1 may protect even against apoptosis induced by ceramide in kidney cells. Human embryonic kidney (HEK)-293 cells stable transfected with SGK-1 wild type (SGK-1wt) and its dominant negative gene (SGK-1dn) have been used in this study. Apoptotic stimuli were induced by C2-ceramide and TNF-α to increase endogenous synthesis of ceramide. Upon activation with these stimuli, SGK-1wt transfected cells have a statistically significant reduction of apoptosis compared with SGK-1dn cells (P<0.001). This protection was dependent on activation of caspase-3 and Poly-ADP-ribose-polymerase-1 (PARP-1) cleavage. SGK-1 and AKT-1 two highly homologous kinases differently reacted to ceramide treatment, since SGK-1 increases in response to apoptotic stimulus while AKT-1 decreases. This enhancement of SGK-1 was dependent on p38-mitogen-activated-protein kinases (p38MAPK), cyclic-adenosine-monophosphate/protein kinase A (cAMP/PKA) and phosphoinositide-3-kinase (PI3K) pathways. Especially, by using selective LY294002 inhibitor, we demonstrated that the most involved pathway in the SGK-1 mediated process of protection was PI3K. Treatment with inhibitor of SGK-1 (GSK650394) significantly enhanced TNF-α-dependent apoptosis in HEK-293 cells overexpressing SGK-1wt. Caspase-3, -8 and -9 selective inhibitors confirmed that SGK-1 reduced the activation of caspase-dependent apoptosis, probably by both intrinsic and extrinsic pathways. In conclusion, we demonstrated that in kidney cells, overexpression of SGK-1 is protective against ceramide-induced apoptosis and the role of SGK-1 can be potentially explored as a therapeutic target in conditions like diabetes, where ceramide levels are increased.

Exercise individualized by TRIMPi method reduces arterial stiffness in early onset type 2 diabetic patients: A randomized controlled trial with aerobic interval training

BACKGROUND Arterial stiffness (AS) and baroreflex sensitivity (BRS) are subclinical markers of vascular diseases in type 2 diabetes (T2D). We evaluated the effects of aerobic interval training (AIT), with loads prescribed according to individual heart rate and lactate profiling obtained during a baseline treadmill test (TRIMPi method), on AS and BRS in patients with early-onset T2D without cardiovascular complications. POPULATION STUDY AND METHODS Twenty-two sedentary overweight T2D patients (aged 57±7years) were randomized to 12-weeks open-label of supervised AIT by TRIMPi (n=8) or unsupervised physical activity as per usual care (SOC) (n=11). Following parameters were evaluated (pre- and post-): anthropometrics; six-minute walking test (6MWT); fasting glucose, insulin, HbA1c; Pulse Wave Velocity (PWV) and Augmentation Index (AIxHR75) using radial approach (SphigmoCor System); BRS using Finapress method. RESULTS Both interventions significantly improved distance walked during 6MWT (AIT 52±21m; SOC 39±24m, p<0.001 for both). PWV significantly improved with AIT (p<0.001) whereas did not vary with SOC (p=0.47). Similar trend was observed for AIxHR75. Resulting percent changes from baseline were significantly better for AIT vs SOC, in both PWV (-15.8±2.1 vs +1.50±3.4%, p<0.001) and AIxHR75 (-28.9±3.2% vs +12.7±2.4%, p<0.001). BRS similarly improved in both groups (p<0.001 for both), as well as body weight, HbA1c and blood pressure. CONCLUSION In sedentary T2D patients, 12-weeks AIT individualized by TRIMPi method improved AS to a greater extent than usual recommendation on physical activity, whilst exerting comparable effects on exercise capacity, glycemic control and body weight. Further researches are needed to ascertain durability of these effects.

The efficacy of plantar stimulation on human balance control.

Abstract Aim: The aim of this study was to evaluate the body sway using firm, foam, and firm textured surfaces on 17 young adults. Method: Displacement of center of pressure (CoP), anteroposterior velocity (VA/P), and mediolateral velocity (VM/L) were measured. Data: The data showed a significant decrease of CoP, VA/P, and VM/L between support surfaces and vision. Results: The results showed that, differently from the firm and foam, the textured surface is able to increase the plantar feedback to maintaining postural control.

Acute changes in neuromuscular activity in vertical jump and flexibility after exposure to whole body vibration

Abstract This study was aimed to investigate the neuromuscular activity after 10 minutes of exposure to a whole body vibration (WBV) session. Twenty male young adults (24.8 ± 2.5 year olds) were randomized and divided into 2 groups: the vibration group (VG) was exposed to 10 minutes of WBV at 35 Hz; performed 10 minutes of WBV at 35 Hz (displacement = 5 mm; magnitude = 5 g); the nonvibrated group (NVG) was the placebo group that maintained the same position on the plate but without exposure to any type of vibration. Subjects were evaluated with counter movement jump (CMJ) and muscular flexibility by means of electromyographic (EMG) analysis recorded on the vastus lateralis (VL), vastus medialis (VM), biceps femoris (BF), and gastrocnemius lateralis (LG). The 10 minutes of WBV showed an increase in muscular flexibility, associated with a decrease of EMG activity in BF (P < .01) and jump height. The latter was associated with a reduction of EMGs activity in BF (P < .01). The control group did not show any significant difference in all considered parameters. These results support the hypothesis that 10 minutes of WBV had effects on flexibility and explosive strength performance influencing neuromuscular behavior through inhibitor effects on antagonist muscles more than the stretch reflex activity on agonist muscles.

Acute effects of static and dynamic stretching on jump performance after 15 min of reconditioning shooting phase in basketball players

BACKGROUND The aim of this study was to assess the effects of static (SS) and dynamic stretching (DS) on vertical jump performance executed before, immediately after and at the end of the shooting phase (i.e., 15 min later), as to simulate the actual conditions preceding a match, in professional basketball players. METHODS Ten elite basketball players (age: 29±6.73 years, height: 194.67±7.75 cm, weight: 91±8.17 kg and BMI 23.8±7.91 kg.m-2) participated to the study. SS and DS protocols were administered during the first training session of the week, 48 hours after the championship match. Stretching protocols consisted in ~7 minutes of general warm-up phase followed by ~8 minutes of SS and DS, performed with a cross-over design., and ~15 minutes of a specific warm-up shooting phase (SP). Vertical jump tests consisted in counter movement jump (CMJ) and CMJ with arm swings (CMJas) and were performed immediately after the end of each stretching phase (preS, postS, postSP). RESULTS A significant decrease (P=0.05; η2partial=0.29) in jumping tests height occurred in CMJas, when performed after the SS (i.e., PostS). However, no significant differences in jumping performances, occurred after the general warm phase and the specific warm-up shooting phase, between the two stretching protocols. CONCLUSIONS These results would indicate that, overall, stretching routines either dynamic or static, performed before a basketball match are transient and affect only marginally leg muscles performance. Stretching routines, particularly the dynamic ones, may be useful to maintain muscle performance before a competition, provided that this latter begins shortly after.