Which short-term effect explains why muscles feel warmer during exercise?

Which short-term effect explains why muscles feel warmer during exercise?

• A. Increased muscle temperature
• B. Lactic acid buildup
• C. Contraction, lengthening, and relaxing at increased rate
• D. More carbon dioxide produced

Answer: (A)

When muscles work, their chemical reactions speed up to release the energy needed for contraction. This energy release also produces heat, so as you exercise more, more heat is generated in the muscles. That extra heat raises the local temperature, which you feel as warmth. Lactic acid buildup is linked to fatigue and a burning sensation, not the warmth. The idea of faster contraction and relaxation describes movement, not the direct cause of warmth. Carbon dioxide production is a respiration byproduct and doesn’t explain why muscles feel warmer.

When muscles work, their chemical reactions speed up to release the energy needed for contraction. This energy release also produces heat, so as you exercise more, more heat is generated in the muscles. That extra heat raises the local temperature, which you feel as warmth.

Lactic acid buildup is linked to fatigue and a burning sensation, not the warmth. The idea of faster contraction and relaxation describes movement, not the direct cause of warmth. Carbon dioxide production is a respiration byproduct and doesn’t explain why muscles feel warmer.