Question

During high-intensity exercise, from where do muscles primarily get their energy?

Answer 1

During high-intensity exercise, muscles first use anaerobic glycolysis to meet their immediate energy needs, utilizing glucose from muscle glycogen and generating lactic acid as a by-product. Aerobic metabolism takes over as oxygen delivery improves, using glucose, pyruvic acid, and fatty acids effectively to produce ATP for energy.

Step-by-step explanation:

During high-intensity exercise, muscles primarily get their energy from anaerobic glycolysis, which is the breakdown of glucose without the need for oxygen. Initially, muscle glycogen serves as the main source, which is quickly converted into glucose and then into ATP and pyruvate. As oxygen supply catches up, the process of aerobic respiration begins, supplementing the muscular energy demands.

When the readily available ATP and creatine phosphate stores are exhausted within seconds, the muscles depend on anaerobic glycolysis, producing ATP in the absence of oxygen, along with a by-product of lactic acid, leading to fatigue and soreness. After about 90 seconds, if oxygen is sufficiently delivered, aerobic metabolism can take over, utilizing glucose, pyruvic acid, and fatty acids. Adequate aerobic respiration is facilitated by elements such as myoglobin in the muscle cells and improvement in the circulatory system due to aerobic training.

Answer 2

During high-intensity exercise, muscles primarily get their energy from the  carbohydrates we intake. These biomolecules are what the body uses to store and produce energy for each activity we do. These substances are very important to be part of our diet.