Effects of greater erythroid Cl^-/HCO₃^- transporter (band 3) expression on ventilation and gas exchange during...

Band 3 protein is a Cl^-/[Formula: see text] transporter on the red blood cell (RBC) surface with an important role in CO₂ excretion. Greater band 3 expression by roughly 20% is found in people with the GP.Mur blood type. Intriguingly, a disproportional percentage of those with GP.Mur excel in field-and-track sports. Could higher band 3 activity benefit an individual's physical performance? This study explored the impact of GP.Mur/higher band 3 expression on ventilation and gas exchange during exhaustive exercise. We recruited 36 nonsmoking, elite male athletes (36.1% GP.Mur) from top sports universities to perform incremental exhaustive treadmill cardiopulmonary exercise testing (CPET). We analyzed CPET data with respect to absolute running time and to individual's %running time and %maximal O₂ uptake. We found persistently higher respiratory frequencies and slightly lower tidal volume in GP.Mur athletes, resulting in a slightly larger increase of ventilation as the workload intensified. The expiratory duty cycle (T_e/T_tot) was persistently longer and inspiratory duty cycle (T_i/T_tot) was persistently shorter for GP.Mur subjects throughout the run. Consequently, end-tidal pressure of carbon dioxide ([Formula: see text], a surrogate marker for alveolar and arterial CO₂ tension-[Formula: see text] and [Formula: see text]) was lower in the GP.Mur athletes during the early stages of exercise. In conclusion, athletes with GP.Mur and higher band 3 expression hyperventilate more during exercise in a pattern that uses a greater fraction of time for expiration than inspiration to increase the rate of CO₂ excretion than increased tidal volume. This greater ventilation response reduced Pco₂ and may help to extend exercise capacity in high-level sports.NEW & NOTEWORTHY Higher expression of the Cl^-/[Formula: see text] transporter band 3 anion exchanger-1 (AE1) on the red blood cell membrane, as in people with the GP.Mur blood type, increases the rate of CO₂ excretion during exercise.