During high-intensity anaerobic exercise, how are blood pH and buffering capacity affected?

During high-intensity anaerobic exercise, how are blood pH and buffering capacity affected?

• A. Substantial reductions in muscle and blood pH occur, and buffering capacity increases, allowing tolerance to lactic acid and delayed fatigue.
• B. Blood pH increases significantly and buffering capacity decreases.
• C. No change occurs in pH or buffering capacity.
• D. Buffering capacity decreases, leading to earlier fatigue.

Answer: (A)

During intense anaerobic work, glycolysis speeds up and rapidly produces hydrogen ions along with lactate. These H+ ions accumulate in muscle and blood, causing a real drop in pH (acidosis), which can impair enzyme function and muscle contraction and contribute to fatigue. The body counters this by boosting buffering capacity through systems like bicarbonate, phosphates, and intracellular proteins. This increased buffering helps neutralize the excess H+, slowing the pH decline and delaying fatigue, even though pH remains lower than normal. The other scenarios don’t fit because pH does not rise during this effort, and buffering capacity isn’t simply unchanged or decreased—the buffering response is part of how the body manages the acidosis that accompanies high-intensity anaerobic metabolism.

During intense anaerobic work, glycolysis speeds up and rapidly produces hydrogen ions along with lactate. These H+ ions accumulate in muscle and blood, causing a real drop in pH (acidosis), which can impair enzyme function and muscle contraction and contribute to fatigue. The body counters this by boosting buffering capacity through systems like bicarbonate, phosphates, and intracellular proteins. This increased buffering helps neutralize the excess H+, slowing the pH decline and delaying fatigue, even though pH remains lower than normal.

The other scenarios don’t fit because pH does not rise during this effort, and buffering capacity isn’t simply unchanged or decreased—the buffering response is part of how the body manages the acidosis that accompanies high-intensity anaerobic metabolism.