Acid-base balance during exercise

How does the aerobic metabolism of glucose increase hydrogen ion concentration?

Carbonic acid is released

How does the anaerobic metabolism of glucose increase hydrogen ion concentration?

Glycolysis produces lactate as a byproduct

What is likely the cause of exercise-induced acidosis?

The production of H+ ions from several different sources

How do cellular proteins buffer hydrogen ions?

The amino acid histidine combines with hydrogen ion to form a weak acid that protects against a decrease in pH

What is NHE and how does it help regulate cell pH?

Sodium-hydrogen exchangers bring sodium into muscle cell and bring hydrogen out

What is MCT and how does it help regulate cell pH?

Monocarboxlate transporters transport 1:1 a lactate and a hydrogen ion

Training has been shown to increase intracellular content of _____ and ______.

Carnosine; hydrogen ion transporters (MCT)

Why is CO2 considered a volatile acid?

It can readily be changed from CO2 to carbonic acid

What determines the concentration of carbonic acid in the blood?

The partial pressure of CO2

What supplements have the capacity to improve performance during high intensity exercise?

Sodium bicarbonate, sodium citrate, beta-alanine

Boosting the blood-buffering capacity by ingestion of sodium bicarbonate ____________

increases time to exhaustion during high intensity exercise

Sodium bicarbonate improves physical performance by _____________

increasing extracellular buffering capacity which increases the transport of hydrogen ions out of the muscle fibres

How do kidneys regulate hydrogen ion concentration?

increasing or decreasing the bicarbonate concentration

What happens to blood and muscle pH during the final stages of an incremental exercise test or during near-maximal exercise of short duration?

a decrease in both blood and muscle pH primarily due to the increase in the production of hydrogen ions in the muscle

Muscle pH is always ____ than blood pH, why?

Lower. Muscle hydrogen ion concentration is higher than that of blood, and muscle buffering capacity is lower than that of blood

What is the first line of defense against a rise in acid production?

intracellular proteins and histidine dipeptides (carnosine) - contribute to 60% of cell’s buffering capacity

At approximately 50% to 60% of VO2 max, blood levels of lactate begin to _____ and blood pH ______ due to _________.

increase; decline; a rise in hydrogen ions in blood

An increase in blood hydrogen levels is sensed by ________ and stimulates ________.

the carotid bodies; alveolar ventilation

Define respiratory compensation

The overall process of buffering lactic acid during exercise