Related Experiment Video
Updated: Aug 5, 2026

12:59
Improving Strength, Power, Muscle Aerobic Capacity, and Glucose Tolerance through Short-term Progressive Strength Training Among Elderly People
Published on: July 5, 2017
Carbohydrate utilization by exercising muscle following pre-exercise glucose ingestion
Clinical Physiology (Oxford, England)
|June 1, 1987
Summary
Prior glucose ingestion significantly boosts exercising muscle
Area of Science:
- Exercise Physiology
- Muscle Metabolism
- Nutritional Biochemistry
Background:
- Understanding fuel utilization during exercise is crucial for optimizing performance and recovery.
- The role of pre-exercise carbohydrate intake on muscle metabolism during low-intensity exercise requires further elucidation.
Purpose of the Study:
- To investigate the impact of prior glucose ingestion on exercising muscle metabolism.
- To quantify substrate utilization, specifically glucose and glycogen, during low-intensity exercise following glucose consumption.
Main Methods:
- Six healthy subjects performed 40-minute leg exercise at 30% maximal oxygen uptake.
- Measurements included leg glucose uptake, substrate oxidation (via respiratory exchange ratio), and metabolite analysis.
- Comparisons were made between exercise with prior glucose ingestion (E + G) and exercise alone (E).
Main Results:
- Leg glucose uptake was 2-3 times higher during E + G compared to E, accounting for 44-48% of oxidative metabolism.
- E + G demonstrated increased pyruvate uptake and suppressed lactate and alanine release compared to E.
- Carbohydrate oxidation was higher during E + G (54-69%) versus E (46-49%), primarily fueled by blood glucose.
Conclusions:
- Glucose ingestion before light exercise enhances glucose uptake and oxidation by exercising muscles.
- A glycogen-sparing effect was observed, with minimal muscle glycogen breakdown during E + G.
- The primary metabolic shift is from fat to glucose oxidation following pre-exercise glucose consumption.
More Related Videos
Related Concept Videos
Introduction to Carbohydrates
Carbohydrates, proteins, and fats are the primary macronutrients in the human diet. However, carbohydrates are the most favored source of energy in the body. They can be found in a wide variety of foods, including whole grains, fruit, and vegetables, in various forms, such as sugars, starch, and dietary fiber. Based on their structure, carbohydrates are classified into three main classes— monosaccharides, disaccharides, and polysaccharides. The body's cells can only utilize simple...
Energy Supply for Muscle Contraction
Skeletal muscle fibers have the unique ability to switch between rest and contraction states, using different sources of ATP for energy. The contraction cycle and Ca2+ transport back into the sarcoplasmic reticulum for relaxation require significant ATP. However, the ATP reserves in muscle fibers are limited and can only sustain contractions for a few seconds. Additional ATP production becomes necessary for prolonged contractions. As a result, muscle fibers generate ATP through various sources,...
Muscle Recovery and Fatigue
Muscle fatigue refers to the decline in a muscle's ability to maintain the force of contraction after prolonged activity. It primarily stems from changes within muscle fibers. Even before experiencing muscle fatigue, one may feel tired and have the urge to stop the activity. This response, known as central fatigue, occurs due to changes in the central nervous system, namely the brain and spinal cord. While there is no single mechanism that induces fatigue, it may serve as a protective response...
Overview of Carbohydrate Metabolism
Carbohydrate metabolism is a fundamental biochemical process that ensures a constant supply of energy to living cells. The most important carbohydrate is glucose, which can be broken down via glycolysis to enter into the Krebs cycle and eventually lead to the production of ATP through oxidative phosphorylation.
Glucose transport into cells is facilitated by a family of transport proteins called GLUT (Glucose Transporters). GLUT4 is the primary glucose transporter for insulin-stimulated glucose...
Glucose transport into cells is facilitated by a family of transport proteins called GLUT (Glucose Transporters). GLUT4 is the primary glucose transporter for insulin-stimulated glucose...
Metabolic States of the Body: The Postabsorptive State
The postabsorptive state usually starts about four hours after a meal and lasts until the next meal is eaten. During this time, the digestive system stops absorbing nutrients, and the body uses stored energy reserves to maintain stable blood glucose levels.
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,...
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,...
Glucose Homeostasis: Regulation of Blood Glucose
Carbohydrates consumed through foods are converted into glucose, a crucial energy source for the body. In the prandial state, high blood glucose levels stimulate the secretion of insulin from the pancreas. Insulin inhibits hepatic glucose production and stimulates glucose uptake and metabolism by muscle and adipose tissue. The excess glucose is converted into glycogen and stored in the liver and muscles.
During fasting, when blood glucose levels are low, the pancreas secretes glucagon. it...
During fasting, when blood glucose levels are low, the pancreas secretes glucagon. it...

