The magnitude of the exercise-induced increase in mitochondria in muscle is independent of training intensity.

• A. True
• B. False
• C. Not stated
• D. Both

Answer: (B)

Muscle mitochondria adapt to meet the higher oxidative demand placed on them, and how much they increase depends on the training stimulus. When you train, energy demand rises, and cells sense this stress through pathways like AMPK and p38 MAPK. These signals boost PGC-1α, the key driver of mitochondrial biogenesis, leading to more mitochondria and greater oxidative enzyme capacity. The stronger the stimulus—typically higher training intensity—the greater the signaling response and the larger the mitochondrial increase, at least up to a ceiling. So the exercise-induced rise in mitochondrial content is not the same regardless of intensity; it grows with intensity and duration, even though some adaptation occurs at lower intensities.