Which muscle fiber produces less lactate and why?

Which muscle fiber produces less lactate and why?

• A. Slow-twitch fibers produce less lactate because they rely on aerobic metabolism.
• B. Fast-twitch fibers produce less lactate.
• C. Both produce the same amount.
• D. Neither produces lactate.

Answer: (A)

Lactate production is tied to the metabolic pathway a muscle fiber mainly uses during activity. Slow-twitch fibers are highly oxidative, with many mitochondria and plenty of blood supply, so they generate most energy through aerobic metabolism. Pyruvate is channeled into the mitochondria and fully oxidized, so relatively little lactate is formed. Fast-twitch fibers, by contrast, rely more on anaerobic glycolysis to meet high-energy demands quickly, which converts more pyruvate into lactate. That’s why slow-twitch fibers produce less lactate. So the best answer is that slow-twitch fibers produce less lactate because they rely on aerobic metabolism.

Lactate production is tied to the metabolic pathway a muscle fiber mainly uses during activity. Slow-twitch fibers are highly oxidative, with many mitochondria and plenty of blood supply, so they generate most energy through aerobic metabolism. Pyruvate is channeled into the mitochondria and fully oxidized, so relatively little lactate is formed. Fast-twitch fibers, by contrast, rely more on anaerobic glycolysis to meet high-energy demands quickly, which converts more pyruvate into lactate. That’s why slow-twitch fibers produce less lactate.

So the best answer is that slow-twitch fibers produce less lactate because they rely on aerobic metabolism.