Timing matters? The effects of two different timing of high protein diets on body composition, muscular performance, and biochemical markers in resistance-trained males.

Background: It is unclear whether resistance training in combination with different timing of protein intake might have differential effects on muscle hypertrophy, strength, and performance. Therefore, we compared the effects of 8 weeks of resistance training combined with two different high-protein diet strategies (immediately pre-and after, or 3 h pre and after exercise) in resistance-trained males. Methods: Forty resistance-trained males (24 ± 4 years) performed 8 weeks of resistance training combined with 2 g kg-1 d-1 protein. Body composition, muscular performance, and biochemical markers were assessed pre and post-intervention. Results: Nine participants (four from 3 h group and five from the immediate group) withdrew from the study. Therefore, 31 participants completed the study. All measures of skeletal muscle mass, Australian pull-up, and muscle strength, significantly increased post-intervention in both groups (p < 0.05). The biochemical marker urea also significantly increased from pre to post in both groups (p < 0.05). There were no significant between-group differences (p > 0.05). Conclusion: High-protein diet enhances muscular performance and skeletal muscle mass in resistance-trained males, irrespective of intake time. Consequently, the total daily protein intake appears to be the primary factor in facilitating muscle growth induced by exercise.

Effects of 8 weeks of resistance training in combination with a high protein diet on body composition, muscular performance, and markers of liver and kidney function in untrained older ex-military men.

Background: The effects of a high protein diet in combination with chronic resistance training (RT) on skeletal muscle adaptation responses in untrained older ex-military men is unknown. Therefore, we compared the effects of 8 weeks of RT in combination with either a high (1.6 g/kg/d) or low protein diet (0.8 g/kg/d) on body composition [skeletal muscle mass (SMM) and body fat percentage (BFP)], muscular strength, power, and endurance (upper and lower body), markers of liver [alanine transaminase (ALT), aspartate aminotransferase (AST), and gamma-glutamyl transferase (GGT)] and kidney (creatinine and urea) function, and lipid profile low-density lipoprotein (LDL), high-density lipoprotein (HDL), and cholesterol levels in a cohort of healthy, untrained older ex-military males. Methods: Forty healthy untrained older ex-military males (age: 61 ± 2 yr, body mass index: 23.2 ± 1.3 kg.m-2) performed 8 weeks (three sessions·w-1) of RT with either 1.6 g/kg/d (RHP; n = 20) or 0.8 g/kg/d of protein (RLP; n = 20). Body composition (assessed by Inbody 720), muscular strength (1-RM for chest and leg press), power (Wingate test), endurance (75% 1-RM for chest and leg press), and markers of liver and kidney function (biochemical kits) were assessed pre and post-intervention. Results: SMM and muscular strength (upper and lower body) increased post-intervention in both groups and were significantly greater in RHP compared to RLP, while muscular power increased to the same extent in both groups (p < 0.05) with no between-group differences (p > 0.05). In contrast, there were no post-intervention changes in muscular endurance, HDL, and BFP remained in either group (p > 0.05). ALT and creatinine significantly increased in RHP compared to RLP while GGT, AST, and urea only increased in the RLP group (p < 0.05). LDL and cholesterol significantly decreased in both groups (p < 0.05). Conclusion: A daily intake of 1.6 g/kg/d protein was superior to 0.8 g/kg/d (current recommended daily intake) for promoting greater improvements in SMM and muscle strength and thus may be a more suitable level of intake for promoting such adaptive responses. Notwithstanding observed between-group differences in ALT and creatinine and the fact that levels remained within normal ranges, it is feasible to conclude that this daily protein intake is efficacious and well tolerated by healthy, untrained older ex-military males.

Increased myocardial dysfunction, dyssynchrony, and epicardial fat across the lifespan in healthy males.

BACKGROUND: Evaluation of sensitive myocardial mechanics with speckle tracking echocardiography (STE) across the lifespan may reveal early indicators of cardiovascular disease (CVD) risk. Epicardial adipose tissue (EAT) and left ventricular (LV) myocardial dyssynchrony; subclinical risk-factors of CVD, are of particular clinical interest. However, the evolution of EAT and LV-dyssynchrony across the lifespan, and their influence on myocardial dysfunction remains unclear. We aimed to establish a profile of the healthy aging-heart using conventional, tissue-Doppler imaging (TDI) and speckle-tracking echocardiography (STE), while also exploring underlying contributions from EAT and LV-dyssynchrony towards LV myocardial mechanics, independent of blood biology. METHODS: Healthy males aged 19-94 years were recruited through University-wide advertisements in Victoria and New-South Wales, Australia. Following strict exclusion criteria, basic clinical and comprehensive echocardiographic profiles (conventional, TDI and STE) were established. LV-dyssynchrony was calculated from the maximum-delay of time-to-peak velocity/strain in the four LV-annulus sites (TDI), and six LV-segments (STE longitudinal and circumferential axes). Epicardial fat diameter was obtained from two-dimensional grey-scale images in the parasternal long-axis. Blood biological measures included glycemia, hsCRP, triglycerides, total cholesterol, high-density and low-density lipoprotein levels. RESULTS: Three groups of 15 were assigned to young (<40 years), middle (40-65 years), and older (>65) aged categories. Five participants were excluded from STE analyses due to inadequate image quality. Decreased longitudinal strain, increased circumferential apical strain and LV twist were age-related. Moreover, independent of blood biology, significant increases were observed across age categories for EAT (young: 2.5 ± 0.9 mm, middle: 3.9 ± 1.0 mm, older 5.7 ± 2.4 mm; p < 0.01), longitudinal STE-dyssynchrony (young: 42 ± 7.7 ms, middle: 58.8 ± 18.9 ms, older 88.6 ± 18.2 ms; p < 0.05), and circumferential-basal STE-dyssynchrony (young: 50.2 ± 20.5 ms, middle: 75.9 ± 20.6 ms, older 97.9 ± 20.2 ms; p < 0.05). These variables collectively explained 37% and 31% (p < 0.01) of longitudinal strain and LV twist, respectively. CONCLUSIONS: This study enabled comprehensive profiling of LV mechanics at different stages of aging using sensitive echocardiographic technology. Novel findings included increased epicardial fat, and both longitudinal and circumferential LV-dyssynchrony across the healthy age groups. These factors may be key underlying contributors to myocardial dysfunction during aging, and their recognition may promote an advanced understanding of early signs of cardiovascular disease.

Left ventricular myocardial dyssynchrony is already present in nondiabetic patients with metabolic syndrome.

The presence of left ventricular (LV) dyssynchrony in individuals with metabolic syndrome (MetS), a predictor of type 2 diabetes (T2D), lacks clarity. We compared LV dyssynchrony in MetS individuals with and without T2D, and healthy control subjects using speckle-tracking imaging echocardiography. Ninety-two MetS participants (64 without, 28 with T2D) and 40 control subjects underwent echocardiographic and clinical/biological analyses. LV-dyssynchrony in the longitudinal axis only was present in all MetS individuals, but was not further exacerbated by T2D. Strong associations were found with systemic inflammation, abdominal obesity, and LV mass. Investigations of myocardial dyssynchrony in the nondiabetic MetS stage might facilitate timely and more effective prevention.