Related Experiment Video
Updated: Aug 10, 2026

Evaluation of Blood Lactate and Plasma Insulin During High-intensity Exercise by Antecubital Vein Catheterization
Published on: May 18, 2018
Effect of intravenous caffeine on liver glycogenolysis during prolonged exercise
Abstract:
Ingestion of caffeine has been reported to enhance performance during prolonged endurance exercise. This effect on performance has been attributed to a caffeine-induced enhancement of lipid oxidation, thereby sparing muscle glycogen. The purpose of this experiment was to determine the effect of caffeine on the rate of liver glycogenolysis during exercise. Adult male rats were given an intravenous injection of caffeine (5 mg X kg-1) or of 0.9% NaCl. One h later they were run on a motor driven treadmill at 28 m X min-1 up a 15% grade for 45 or 90 min. Liver and muscles were frozen, and blood was collected for analysis. No significant differences were found between caffeine- and saline-injected rats in liver or muscle glycogen, plasma free fatty acid, insulin, glucagon, blood glucose, or blood glycerol. Liver adenosine 3',5'-cyclic monophosphate was essentially the same in caffeine- and saline-injected rats after 90 min of exercise. In a separate study, injection of 5 or 25 mg caffeine per kg body weight immediately prior to a 60-min bout of exercise had no effect on the rate of liver muscle glycogenolysis or on any of the hormones and metabolites studied. We conclude that in the rat, blood levels of caffeine in the range of 3.7 to 29 micrograms X ml-1 have no effect on liver adenosine 3',5'-cyclic monophosphate or the rate of liver glycogenolysis during prolonged treadmill running.
More Related Videos
08:32Quantification of Subcellular Glycogen Distribution in Skeletal Muscle Fibers using Transmission Electron Microscopy
Published on: February 7, 2022
04:54Using a Combination of Indirect Calorimetry, Infrared Thermography, and Blood Glucose Levels to Measure Brown Adipose Tissue Thermogenesis in Humans
Published on: June 2, 2023
Related Concept Videos
Energy Supply for Muscle Contraction
Muscle Recovery and Fatigue
Exercise and Cardiovascular Response
Light to moderate physical activity initiates a series of interconnected responses in the body. The heart rate modestly increases in anticipation of the workout, followed by widespread vasodilation as oxygen consumption by skeletal muscles increases. This results in decreased peripheral resistance, increased capillary blood flow, and accelerated...
Metabolic States of the Body: The Postabsorptive State
Initially, glycogen stored in the liver is broken down to release glucose into the bloodstream, while glycogen in the muscles is broken down to supply glucose for energy directly within the muscle cells. As glycogen stores diminish,...
Metabolic States of the Body: Fasting and Starvation
Glucose Homeostasis: Regulation of Blood Glucose
During fasting, when blood glucose levels are low, the pancreas secretes glucagon. it...