Effect of a small dose of alcohol on the endurance performance of trained cyclists

AIM: The aim of this study was to investigate the effect of an acute small ethanol (EtOH) dose (0.5 ml EtOH/kg fat-free mass, combined with carbohydrate) in a drink on endurance performance of trained cyclists. METHODS: Thirteen well-trained male cyclists took part in this study. A 60-min cycling endurance performance test (time trial) was performed in a calorimetric chamber after drinking an EtOH (30 +/- 1.8 ml) or a non-EtOH control (C) drink. RESULTS: Overall, EtOH induced a significant decrease in the average cycling power output (PO) (EtOH: 233 +/- 23 W versus C: 243 +/- 24 W, P < 0.01). The time course of mechanical PO showed an early decrease during the EtOH trial as compared to C (P < 0.01). Due to the lower PO, oxygen consumption, carbon dioxide production and glucose oxidation were significantly lower (P < 0.05) as compared to C. Relative to PO, heart rate response and ratings of perceived exertion (RPE) were increased by EtOH as compared to C (P < 0.05). In contrast, EtOH did not influence gross work efficiency, glycaemia and blood lactate concentration. CONCLUSIONS: These results show that the acute low dose of EtOH decreased endurance performance. An increase of cardio-vascular strain and psychobiological mechanisms may explain this decrease of endurance performanc

Effect of a small dose of alcohol on the endurance performance of trained cyclists.

AIM: The aim of this study was to investigate the effect of an acute small ethanol (EtOH) dose (0.5 ml EtOH/kg fat-free mass, combined with carbohydrate) in a drink on endurance performance of trained cyclists. METHODS: Thirteen well-trained male cyclists took part in this study. A 60-min cycling endurance performance test (time trial) was performed in a calorimetric chamber after drinking an EtOH (30 +/- 1.8 ml) or a non-EtOH control (C) drink. RESULTS: Overall, EtOH induced a significant decrease in the average cycling power output (PO) (EtOH: 233 +/- 23 W versus C: 243 +/- 24 W, P < 0.01). The time course of mechanical PO showed an early decrease during the EtOH trial as compared to C (P < 0.01). Due to the lower PO, oxygen consumption, carbon dioxide production and glucose oxidation were significantly lower (P < 0.05) as compared to C. Relative to PO, heart rate response and ratings of perceived exertion (RPE) were increased by EtOH as compared to C (P < 0.05). In contrast, EtOH did not influence gross work efficiency, glycaemia and blood lactate concentration. CONCLUSIONS: These results show that the acute low dose of EtOH decreased endurance performance. An increase of cardio-vascular strain and psychobiological mechanisms may explain this decrease of endurance performance

Matrix effects on the optical response of silver nanoclusters

We report absorption spectra for Ag7, Ag9, and Ag11 in an argon matrix grown at a temperature of 28 K and compare them with previous spectra of the same species measured in matrices of argon grown at lower temperatures as well as in neon matrices. We discuss the discrepancies in the light of the matrix crystallinity and show that this leads to an understanding of the influence of the matrix on the optical response of small clusters

Glucose-fructose beverages do not alter the effects of training on lactate metabolism

Glucose-fructose beverages do not alter the effects of training on lactate metabolism Rosset R., Egli L., Cros J., Schneiter P. and Tappy L. and Lecoultre V. Department of Physiology, University of Lausanne, Lausanne, Switzerland. Introduction It is generally accepted that lactate is produced by skeletal muscle during exercise, and is either used in adjacent muscle fibers (lactate shuttle) or recycled to glucose in the liver. We have shown that ingestion of fructose-containing drinks stimulates lactate production and release from the liver during exercise, and that fructose-derived lactate is subsequently used as an energy substrate by muscle. The regulation of this liver to muscle fructose-lactate shuttle remains unknown. In this study, we assessed whether consumption of fructose-containing beverages alters the effects of training on fructose and lactate metabolism. Methods Two groups of eight sedentary male subjects were endurance-trained for three weeks while ingesting 489 mL/h of either a 9.8%-glucose 6.2%-fructose beverage (GLUFRU) or water (C) during exercise training sessions. An incremental test to exhaustion and a metabolic test were performed before and after the interventions to assess training adaptations and substrate use during endurance-type exercise. Indirect calorimetry, [1-13C]lactate and [6,6-2H2]glucose were used to calculate plasma lactate appearance, clearance and oxidation and glucose kinetics. Results Anthropometrics and performance parameters were similar in both groups at baseline. Plasma glucose concentrations (+1±3 vs. +3±3 % vs. baseline values), glucose rate of appearance (+3±7 vs. +2±3 %) and metabolic clearance (+6±8 vs. +1±5 %) remained stable after both GLUFRU and C training (all p=n.s.). Overall, lactate concentrations were decreased after intervention in both GLUFRU and C, but not differently between groups (-10±5 vs. -20±4 %; p<0.01 vs. baseline, p=n.s. between GLUFRU and C), as a result of an increased lactate metabolic clearance (+26.5±11.4 vs. +17.5±10.2 mL·min-1; p=0.01 vs. baseline, p=0.56 between GLUFRU and C). Lactate appearance (+10±6 vs. -4±9 %) and oxidation (+9±6 vs. - 6±9 %) remained unchanged across time and conditions (all p=n.s.). Maximal oxygen consumption (+287±53 vs. +249±104 mL·min-1) and power eliciting lactate threshold (+25±5 vs. +25±8 W) were similarly increased in GLUFRU and C (both p<0.01 vs. baseline, p=n.s. between GLUFRU and C). Discussion These data corroborate our earlier observation that fructose is converted into lactate by the liver and subsequently oxidized during exercise. Endurance training did not alter liver lactate release, but increased lactate metabolic clearance. The effects of endurance training were not differently altered by the consumption of fructose during training sessions, however

Optical absorption of small silver clusters: Agn, (n=4–22)

We present a joint theoretical and experimental investigation of the absorption spectra of silver clusters Agn (4<=n<=22). The experimental spectra of clusters isolated in an Ar matrix are compared with the calculated ones in the framework of the time-dependent density functional theory. The analysis of the molecular transitions indicates that the s-electrons are responsible for the optical response of small clusters (n<=8) while the d-electrons play a crucial role in the optical excitations for larger n values

Effects of Dietary Protein and Fat Content on Intrahepatocellular and Intramyocellular Lipids during a 6-Day Hypercaloric, High Sucrose Diet: A Randomized Controlled Trial in Normal Weight Healthy Subjects.

Sucrose overfeeding increases intrahepatocellular (IHCL) and intramyocellular (IMCL) lipid concentrations in healthy subjects. We hypothesized that these effects would be modulated by diet protein/fat content. Twelve healthy men and women were studied on two occasions in a randomized, cross-over trial. On each occasion, they received a 3-day 12% protein weight maintenance diet (WM) followed by a 6-day hypercaloric high sucrose diet (150% energy requirements). On one occasion the hypercaloric diet contained 5% protein and 25% fat (low protein-high fat, LP-HF), on the other occasion it contained 20% protein and 10% fat (high protein-low fat, HP-LF). IHCL and IMCL concentrations (magnetic resonance spectroscopy) and energy expenditure (indirect calorimetry) were measured after WM, and again after HP-LF/LP-HF. IHCL increased from 25.0 ± 3.6 after WM to 147.1 ± 26.9 mmol/kg wet weight (ww) after LP-HF and from 30.3 ± 7.7 to 57.8 ± 14.8 after HP-LF (two-way ANOVA with interaction: p &lt; 0.001 overfeeding x protein/fat content). IMCL increased from 7.1 ± 0.6 to 8.8 ± 0.7 mmol/kg ww after LP-HF and from 6.2 ± 0.6 to 6.9 ± 0.6 after HP-LF, (p &lt; 0.002). These results indicate that liver and muscle fat deposition is enhanced when sucrose overfeeding is associated with a low protein, high fat diet compared to a high protein, low fat diet