The relationship between the isocapnic buffering phase and maximal accumulated oxygen deficit in athletes

This study aimed to investigate the relationship between the isocapnic buffering (IB) phase and maximal accumulated oxygen deficit (MAOD) in athletes.

Twenty-two active male athletes (19.7 ± 1.4 years) participated in an incremental test to determine maximal oxygen uptake (V̇O_2max), the intensity associated with V̇O_2max (vVO_2max), the anaerobic threshold (AT), the respiratory compensation point (RCP), and IB, 6 submaximal efforts to construct the V̇O₂-velocity relationship, a supramaximal effort to determine MAOD, and the Wingate Anaerobic test. The IB was calculated as the difference in both oxygen uptake (IB_VO2) and running velocity (IBv) between the RCP and AT, and expressed in absolute or relative values.

MAOD was positively associated with absolute and relative IB_VO2 and IB_V (rs=0.825, 0.753, 0.675, and 0.630, respectively; all Holm-adjusted p ≤ 0.002). In exploratory analyses, peak power remained associated after false discovery rate (FDR) adjustment with absolute and relative IB_VO2, IB_V, and MAOD (q ≤ 0.047), while mean power remained associated with absolute and relative IB_VO2 and MAOD (q ≤ 0.047). No statistically significant association was detected between V̇O_2max and either MAOD or the IB phase.

These findings suggest that the IB phase may be a potential physiological indicator associated with anaerobic capacity in athletes. A high buffering capacity may allow anaerobic glycolysis to persist longer, thereby providing greater anaerobic capacity.