The present study investigated the effect of pre-exercise metabolic alkalosis on the primary component of oxygen uptake (VO₂) kinetics, characterized by ₁. Seven healthy physically active nonsmoking man, aged 22.4 ± 1.8 (mean ± SD) years, VO₂max 50.4 ± 4 ml ^. min^{-1 .} kg^-1, performed two bouts of cycling, corresponding to 40 and 87 % of VO₂max, lasting 6 minutes each, separated by 20 minutes pause, once as a control study, and a few days later at about 90 minutes after ingestion of 3 mmol ^. kg BW^-1 of NaHCO₃. Blood samples for measurements of bicarbonate concentration [HCO₃^-]_b, and hydrogen ion concentration [H⁺]_b were taken from antecubital vein via catheter. VO₂ was measured continuously breath-by-breath. The values of ₁ were calculated using six various approaches published in the literature, in order to choose the model best suited for the analysis of our experimental data. Pre-exercise level of [HCO₃^-]_b after ingestion of NaHCO₃ was significantly elevated (p<0.01) when compared to the control study (28.96 ± 2.11 vs. 24.84 ± 1.18 mmol ^. l^-1 ; p<0.01) and [H⁺]_b was significantly (p<0.01) reduced (42.79 ± 3.38 nmol ^. l^-1 vs. 46.44 ± 3.51 nmol ^. l^-1). This shift (p<0.01) was also present during both bouts of exercise. During cycling at 40 % of VO₂max no significant effect of the pre-exercise alkalosis on the magnitude of ₁ was found. However, during cycling at 87 % of VO₂max the ₁ calculated by all six approaches was significantly (p<0.05) reduced when compared to the control study. The ₁ calculated as in Borrani et al. (2001) was reduced on average by from 7.9 s (± 2.6 s), which was significantly different from zero both with the t-Student test (p=0.011) and with the Wilcoxon signed ranks test (p=0.014).