Dose caffeinated energy drink is a consideration issue for endurance performance.

Caffeinated energy drinks are commonly taken to improve exercise performance, but there are few studies on the influence of different doses on an athlete's performance. We conducted a double-blind, randomized, counter-balanced, and crossover research study to examine the effects of low caffeinated energy drink (Low ED) or high caffeinated energy drink (High ED) supplement on the performance, haematological response, and oxidative stress in triathletes. Twelve male participants underwent three testing sessions separated by weekly intervals, consisting of sprint triathlon training (0.75 km swim, 20 km cycle, and 5 km run). Before and during the trials, participants were randomly provided with either placebo (PLA) group, Low ED group, or High ED group. Exercise performance in the High ED group decreased significantly compared with the PLA and Low ED groups (p < 0.05). However, participants in the Low ED group also experienced an improved performance (p = 0.054). Analysis of variance revealed no differences among the three groups in cortisol and testosterone levels, or the Borg Rating of Perceived Exertion score (p > 0.5). Furthermore, superoxide dismutase (SOD) was reduced with exercise and were lowest in the High ED group. However, compared with PLA, a significant decrease of thiobarbituric acid reactive substances (TBARS) was observed in Low ED and High ED groups (p < 0.05). This indicates that caffeinated energy drink consumption may improve performance and reduce oxidative stress in sprint triathlon athletes. However, individual differences should be considered when supplementing with caffeinated energy drinks to decrease side effects.

Protein supplementation enhances cerebral oxygenation during exercise in elite basketball players.

OBJECTIVE: The aim of the present study was to examine cerebral oxygenation during high-intensity exercise in elite basketball players who consumed supplements with different whey protein contents after a short postexercise recovery to determine whether changing whey protein content in carbohydrate-based supplementation influences cerebral hemodynamic response when the supplement was consumed during a 2-h recovery after a 1-h exercise challenge. METHODS: This was a randomized, counterbalanced crossover study. Fifteen Division 1 collegiate basketball players (18-20 y) consumed 6.25 kcal/kg of either high-protein (36% protein in total calorie) or an isocaloric low-protein (12% protein in total calorie) control supplement in a carbohydrate-based drink immediately after a 1-h cycling (70% of maximal oxygen consumption [VO2max]). After a 2-h rest, the athletes were challenged on a cycloergometer at 80% VO2max. Blood perfusion (total hemoglobin) and oxygen saturation of frontal brain were continuously measured by near-infrared spectroscopy during the cycling. RESULTS: Before the cycloergometer test, high-protein supplementation increased peak insulin response and lowered glucose increases during the recovery compared with the low-protein trial. High-protein supplementation enhanced increases in cerebral oxygen saturation (P < 0.01) and attenuated increases in cerebral blood perfusion (total hemoglobin; P < 0.01) during the cycloergometer exercise; and resulted in a 16% longer cycling time (from 474 ± 49 s to 553 ± 78 s, P < 0.05), compared with the low-protein trial. CONCLUSION: Enhanced fatigue recovery after consumption of a high-protein supplement is associated with enhanced cerebral oxygenation against exercise challenge, which spares brain blood demand for periphery.

Hydrolysis of magnetic amylase-imprinted poly(ethylene-co-vinyl alcohol) composite nanoparticles.

Molecularly imprinted polymers (MIPs) have frequently been employed as recognition elements in sensing applications, or for the controlled delivery of small molecule drugs. An equally important but less well studied application is the use of MIPs in the binding and immobilization of active enzymes. In this study, magnetic MIPs (MMIPs) recognizing the enzyme amylase were prepared using phase inversion of poly(ethylene-co-vinyl alcohol) (EVAL) solutions with 27-44 mol % ethylene in the presence of amylase. The size distribution, specific surface area, magnetization, and composition were characterized by dynamic light scattering (DLS), Brunauer-Emmett-Teller (BET) analysis, superconducting quantum interference devices (SQUID), and X-ray diffraction (XRD), respectively. The mean size of MMIPs was ~100 nm and the magnetization was 14.8 emu/g. The activities of both bound template and rebound enzyme was established by measuring glucose production via starch hydrolysis, at different temperatures, for MIPs with different compositions (wt % EVALs and mol % ethylene). The highest hydrolysis activity of MMIPs (obtained with 32 mol % ethylene) was found to be 1545.2 U/g. Finally, compared to the conventional catalysis process, MMIPs have the advantages of high surface area, suspension, easy removal from reaction, and rapid reload of enzyme. The good activity of amylase MMIPs persists after 50 cycles of starch hydrolysis.