Integrated Pathways of Fuel Metabolism and Exercise

Flashcards based on lecture notes about the integrated pathways of fuel metabolism and exercise.

Type I Muscle Fibers

Muscle fibers recruited during low-intensity exercise; characterized by high oxidative capacity and fatigue resistance.

Type IIa Muscle Fibers

Muscle fibers recruited during medium-intensity exercise; offer moderate force and fatigue resistance.

Type IIb Muscle Fibers

Muscle fibers recruited during high-intensity exercise; provide high force output but fatigue quickly.

Phosphate Creatine System

Primary ATP source during the first 10 seconds of exercise.

Anaerobic Glycolysis

ATP source during exercise lasting 10-60 seconds.

Aerobic Glycolysis and Beta-Oxidation

Predominant ATP sources during exercise lasting greater than 20 minutes

Glycolytic Flux

The rate at which glucose is converted into pyruvate through the glycolysis pathway

Higher Mitochondrial Density

Metabolic adaptation seen in marathon runners allowing for better fat oxidation and delayed lactate threshold.

Lactate Threshold

The point at which lactate begins to accumulate in the blood at a faster rate than it is removed.

Insulin

Hormone that is typically low during starvation and low carbohydrate diets which ultimately leads to increased lipolysis and ketogenesis

Glucagon

Hormone that is high during starvation and low carbohydrate diets which ultimately leads to increased lipolysis and ketogenesis

Ketogenesis

Process that is increased during starvation and low carbohydrate diets.

GLUT4

Glucose transporter that is insulin-sensitive and responsible for glucose uptake in normal metabolism.

Insulin Resistance

A condition where cells become less responsive to insulin, leading to decreased glucose uptake.

Gluconeogenesis

Increased use of alternative pathways as a result of insulin resistance