A parameter which indicates the acid-base balance in the body. Base excess is defined as the amount of protons (H+ ions) required to return the pH of blood to 7.35 if the partial pressure of carbon dioxide was adjusted to normal. Base excess is affected by blood lactate, with which it has a high correlation, and organic acids which accumulate during and after exercise. It may, therefore, reflect adaptation to exercise. Normal base excess values are between −2.3 and +2.3 mmol l−1. A base excess value of more than +3 mmol l−1 indicates metabolic alkalosis whereas a base excess value of more than +3 mmol l−1 indicates metabolic acidosis.
Subjects: Sports and Exercise Medicine.