How does heat buildup in muscle contribute to fatigue during prolonged exercise?

• A. It increases oxygen delivery to the muscles, enhancing endurance.
• B. It interferes with enzyme activity, reducing the efficiency of muscle contractions.
• C. It stimulates the production of ATP, providing more energy for muscle activity.
• D. It accelerates the removal of metabolic waste products, preventing fatigue.

Answer: (B)

Verified step by step guidance

1. Understand the physiological process of muscle contraction: Muscle contraction requires ATP, and during prolonged exercise, ATP production relies heavily on aerobic and anaerobic metabolism, which generates heat as a byproduct.
2. Recognize the role of enzymes in muscle activity: Enzymes are proteins that catalyze biochemical reactions, including those involved in ATP production and muscle contraction. Their activity is sensitive to temperature changes.
3. Analyze the impact of heat buildup: Excessive heat can denature or alter the structure of enzymes, reducing their efficiency and interfering with the biochemical processes necessary for effective muscle contractions.
4. Connect heat buildup to fatigue: When enzyme activity is compromised, the efficiency of ATP production and muscle contraction decreases, leading to reduced muscle performance and fatigue during prolonged exercise.
5. Conclude the explanation: Heat buildup does not enhance oxygen delivery, stimulate ATP production, or accelerate waste removal. Instead, it interferes with enzyme activity, which is the primary factor contributing to reduced muscle efficiency and fatigue.