Which term describes the production of acid that causes fatigue during intense exercise?

Which term describes the production of acid that causes fatigue during intense exercise?

• A. Tidal volume
• B. Lactic acid production
• C. Respiratory rate
• D. Residual volume

Answer: (B)

During very intense exercise, the muscles quickly require more energy than oxygen can supply for aerobic respiration. When oxygen is limited, glucose is broken down through glycolysis and, without enough oxygen to fully process the pyruvate, it is converted into lactic acid. The build-up of lactic acid (and the accompanying hydrogen ions) lowers the pH inside the muscle, slowing enzyme activity and weakening muscle contractions, which leads to fatigue and that familiar burning sensation. So, the term that best describes the production of acid causing fatigue is lactic acid production. Tidal volume refers to the amount of air moved with each breath, respiratory rate is the number of breaths per minute, and residual volume is the air remaining in the lungs after a full exhale—none of these describe acid production or fatigue.

During very intense exercise, the muscles quickly require more energy than oxygen can supply for aerobic respiration. When oxygen is limited, glucose is broken down through glycolysis and, without enough oxygen to fully process the pyruvate, it is converted into lactic acid. The build-up of lactic acid (and the accompanying hydrogen ions) lowers the pH inside the muscle, slowing enzyme activity and weakening muscle contractions, which leads to fatigue and that familiar burning sensation.

So, the term that best describes the production of acid causing fatigue is lactic acid production.

Tidal volume refers to the amount of air moved with each breath, respiratory rate is the number of breaths per minute, and residual volume is the air remaining in the lungs after a full exhale—none of these describe acid production or fatigue.