Coffee Increases Post-Exercise Muscle Glycogen Recovery in Endurance Athletes: A Randomized Clinical Trial

Coffee is one of the most widely consumed beverages worldwide and caffeine is known to improve performance in physical exercise. Some substances in coffee have a positive effect on glucose metabolism and are promising for post-exercise muscle glycogen recovery. We investigated the effect of a coffee beverage after exhaustive exercise on muscle glycogen resynthesis, glycogen synthase activity and glycemic and insulinemic response in a double-blind, crossover, randomized clinical trial. Fourteen endurance-trained men performed an exhaustive cycle ergometer exercise to deplete muscle glycogen. The following morning, participants completed a second cycling protocol followed by a 4-h recovery, during which they received either test beverage (coffee + milk) or control (milk) and a breakfast meal, with a simple randomization. Blood samples and muscle biopsies were collected at the beginning and by the end of recovery. Eleven participants were included in data analysis (age: 39.0 ± 6.0 years; BMI: 24.0 ± 2.3 kg/m2; VO2max: 59.9 ± 8.3 mL·kg−1·min−1; PPO: 346 ± 39 W). The consumption of coffee + milk resulted in greater muscle glycogen recovery (102.56 ± 18.75 vs. 40.54 ± 18.74 mmol·kg dw−1; p = 0.01; d = 0.94) and greater glucose (p = 0.02; d = 0.83) and insulin (p = 0.03; d = 0.76) total area under the curve compared with control. The addition of coffee to a beverage with adequate amounts of carbohydrates increased muscle glycogen resynthesis and the glycemic and insulinemic response during the 4-h recovery after exhaustive cycling exercise.

Beta2-adrenoceptor agonist salbutamol increases leg glucose uptake and metabolic rate but not muscle glycogen resynthesis in recovery from resistance exercise of the quadriceps in lean young men

Content: Beta2-agonists evoke potent acute increases in peripheral glucose uptake and energy expenditure at rest. Exercise has been shown to blunt these effects. Whether this attenuation is extended into recovery from exercise is unknown. Objective: To examine the effect of beta2-agonists on leg glucose uptake and leg metabolic rate in recovery from exercise. Design: In a randomized, placebo-controlled, cross-over study using arteriovenous balance technique and analysis of thigh muscle biopsies we investigated the effect of 24mg oral salbutamol (a selective beta2-agonist) on leg glucose, oxygen, and lactate at rest, during exercise, and in recovery, as well as on muscle glycogen resynthesis. Participants: Healthy, lean, young men (n=12). Results: Leg glucose uptake tended to be two-fold higher at rest (0.22+/-0.12mmol/min, P=0.06). Accumulated leg glucose uptake was higher in recovery (21.1+/-6mmol, P=0.018) with salbutamol, but not during exercise. Leg oxygen uptake was 80% greater at rest (11+/-2.1mmol/min, P<0.01). Accumulated leg oxygen uptake was higher in recovery (1755+/-348mL, P<0.01) with salbutamol, but not during exercise. Muscle glycogen was lower with salbutamol 0.5h (109+/-25mmol/mg dry-weight, P<0.01) and 5h (101+/-19mmol/mg dry-weight, P<0.01) into recovery, suggestive of augmented glycogen utilization during exercise. There was no difference in glycogen resynthesis or glycogen synthase activity in the 5-hour recovery period with salbutamol. Conclusions: These findings suggest that while resistance exercise confounds the augmentation of leg glucose uptake and metabolic rate induced by beta2-agonist at rest, this suppression is not conserved into recovery from exercise.

Effects of Oral Resveratrol Supplementation on Glycogen Replenishment and Mitochondria Biogenesis in Exercised Human Skeletal Muscle

The present study aimed to investigate the effect of oral resveratrol supplementation on the key molecular gene expressions involved in mitochondria biogenesis and glycogen resynthesis in human skeletal muscle. Nine young male athletes participated in the single-blind and crossover designed study. All subjects completed a 4-day resveratrol and placebo supplement in a randomized order while performing a single bout of cycling exercise. Immediately after the exercise challenge, the subjects consumed a carbohydrate (CHO) meal (2 g CHO/Kg body mass) with either resveratrol or placebo capsules. Biopsied muscle samples, blood samples and expired gas samples were obtained at 0 h and 3 h after exercise. The muscle samples were measured for gene transcription factor expression by real-time PCR for glucose uptake and mitochondria biogenesis. Plasma glucose, insulin, glycerol, non-esterified fatty acid concentrations and respiratory exchange ratio were analyzed during post-exercise recovery periods. The results showed that the muscle glycogen concentrations were higher at 3 h than at 0 h; however, there were no difference between resveratrol trial and placebo trial. There were no significantly different concentrations in plasma parameters between the two trials. Similarly, no measured gene expressions were significant between the two trials. The evidence concluded that the 4-day oral resveratrol supplementation did not improve post-exercise muscle glycogen resynthesis and related glucose uptake and mitochondrial biosynthesis gene expression in men.

Effect of Capsinoids Supplementation on Fat Oxidation and Muscle Glycogen Restoration During Post-exercise Recovery in Humans

Background: Capsinoids (CSN), the novel non-pungent capsaicin analogs have been reported to promote metabolic health and exercise tolerance. However, the effect of CSN on fat oxidation and changes in skeletal muscle glycogen levels during post-exercise recovery has not been investigated in humans. Purpose: We examined the effect of CSN supplementation on energy reliance, glycogen resynthesis and molecular proteins in the skeletal muscle of young adults during post-exercise recovery. Methods: In this crossover-designed study, nine healthy adult male volunteers (aged 21.4±0.2 years, BMI 21.9±1.3 kg/m2 ) completed a 60-min cycling exercise at 70% VO2max. Participants consumed either CSN (12 mg, single dosage) or placebo capsules with a high-carbohydrate meal (2 g carb/kg bodyweight) immediately after exercise. Biopsied muscle samples (vastus lateralis), blood and gaseous samples were obtained during 3h post-exercise recovery period. Results: We found that oral CSN supplementation right after exercise significantly altered the energy reliance on fat oxidation during recovery. This was evidenced by lower respiratory exchange ratio (RER) and higher fat oxidation rate in CSN trial. Despite, acute CSN dosage does not contribute to enhance the glycogen replenishment in skeletal muscle during 3h recovery. We identified no significant differences in postprandial glucose and insulin area under the curve in both trials. Western blot data showed increased muscle GLUT4 expression, but no significant response of p-Akt/Akt ratio with CSN during post-exercise recovery. Conclusion: Our findings conclude that acute CSN intake could change energy reliance on fat oxidation, but unable to enhance muscle glycogen resynthesis during post-exercise recovery. Thus, ergogenic properties of CSN in relevance to muscle glycogen restoration following exercise needs to be further investigated in young adults.

The dynamics of energy metabolism in the tick embryo

The cattle tick Rhipicephalus (Boophilus) microplus is an ectoparasite capable of transmitting a large number of pathogens, causing considerable losses in the cattle industry, with substantial damage to livestock. Over the years, important stages of its life cycle, such as the embryo, have been largely ignored by researchers. Tick embryogenesis has been typically described as an energy-consuming process, sustaining cell proliferation, differentiation, and growth. During the embryonic stage of arthropods, there is mobilization of metabolites of maternal origin for the development of organs and tissues of the embryo. Glycogen resynthesis in late embryogenesis is considered as an effective indicator of embryonic integrity. In the cattle tick R.(B. (B.) microplus, glycogen resynthesis is sustained by protein degradation through the gluconeogenesis pathway at the end of the embryonic period. Despite recent advancements in research on tick energy metabolism at the molecular level, the dynamics of nutrient utilization during R. (B.) microplus embryogenesis is still poorly understood. The present review aims to describe the regulatory mechanisms of carbohydrate metabolism during maternal-zygotic transition and identify possible new targets for the development of novel drugs and other control measures against R. (B.) microplus infestations.

Oral Capsinoids Supplementation May not Enhance Glycogen Recovery against Exercise-Induced Loss in Exercised Human Skeletal Muscle

We investigated whether post-exercise capsinoids (CSN) supplementation could enhance muscle glycogen resynthesis via GLUT4/Akt expressions in human skeletal muscle. Nine male college students (aged 21.4&plusmn;0.2 years, BMI 21.9&plusmn;1.3 kg/m2, VO2max 47.1&plusmn;1.8 ml/kg/min) participated in this crossover designed study, and completed a 60-min cycling exercise at 70% VO2max. Immediately after exercise, participants consumed high-carbohydrate diet (2 g carb/kg bodyweight) with CSN (12 mg, single dosage) or placebo. Biopsied muscle samples (vastus lateralis) were obtained immediately (0h) and 3h after exercise. Blood and expired gas samples were collected before and after exercise. We found oral CSN supplementation immediately after exercise was unable to enhance glycogen resynthesis in exercised human skeletal muscle. Despite, CSN could alter the energy reliance on fat oxidation during post-exercise recovery, based on gaseous exchange measurement (NEFA and glycerol). We further identified no significant differences in postprandial glucose/insulin area under curve in both trials. Western blot data showed no significant response of p-Akt/Akt ratio with CSN during post-exercise recovery. Inconsistent with glycogen levels, muscle GLUT4 expression was significantly elevated at 3h in CSN trial. Our findings emphasize the necessity of further evidences to confirm the ergogenic properties of CSN in connection with glycogen recovery in exercised human skeletal muscle.