Effects of a prior exhausting exercise on peak O2 uptake, lactate and ventilatory thresholds during ramp exercise in men

Abstract

Aim of the study was to evaluate the effects of a prior exhausting exercise on maximum performance, lactate threshold (LaT) and first (V̇et1) and the second (V̇et2) ventilatory thresholds. Eight young males performed a maximum ramp (25 W·min−1) cycloergometric test before and 5 hours after an exhausting exercise. During tests, breath‐by‐breath measurements of gas exchange, power output and blood lactate concentration ([La−]) were obtained. LaT together with V̇et1, V̇et2 and the amplitude of the isocapnic buffering range of exercise (V̇et2 − V̇et1) were then calculated. After exhaustion it resulted that: i) the peak power significantly decreased from 247±11 W to 234±12 W (P<0.05), and a lower V̇o2 peak (2.77±0.15 L·min−1 vs. 2.65±0.14 L·min−1, P<0.05) was observed; ii) LaT occurred at higher V̇o2 (1.96±0.10 L·min−1 and 2.15±0.15 L·min−1 before and after exhaustion, respectively; P<0.05), whereas V̇et1 was similar in both tests; iii) V̇et2 appeared at lower V̇o2 (2.63±0.16 L·min−1 and 2.47±0.17 L·min−1 before and after exhaustion, respectively; P<0.05), and iv) V̇et2 − V̇ET1 decreased significantly by 21±4% (P<0.05). These results show that prior exhausting exercise affected the metabolic and respiratory response of a following exercise and are compatible with the hypothesis that prior exhausting exercise alters acid‐base status and the activity of the enzymes involved in CO2 transport and buffering systems. The study was supported by a grant of Fondazione CARIPLO.