Sodium bicarbonate ingestion prior to sprint-interval exercise causes a 28% reduction in mitochondrial respiration via Complex I and a 23% reduction in maximal electron transport system capacity 24 hours after exercise in healthy young men, an effect not observed with placebo.

When sodium bicarbonate is taken before intense exercise, it raises blood pH and reduces muscle acidity during recovery. This change prevents damage to key proteins that move lactate and acid out of muscle cells. As a result, the muscle cells do not activate the normal stress signals that boost energy production in mitochondria. Without those signals, the mitochondria reduce their activity at Complex I, cutting down how much energy they produce for 24 hours after exercise.