Maximal accumulated oxygen deficit expressed relative to the active musclemass for cycling in untrained male and female subjects

The purpose of the present study was to determine if gender differences exi st in the maximal accumulated oxygen deficit (MAOD) or in the blood lactate (Lac(-)) and catecholamine responses to the MAOD test (120% peak oxygen up take to exhaustion). The MAOD for cycling was measured in ten untrained mal e and ten untrained female subjects using the method described by Medbo et al. (Anaerobic capacity determined by maximal accumulated oxygen deficit. J Appl Physiol 64; 50-60, 1988). Blood Lac(-) and catecholamine concentratio ns were measured at rest, exhaustion and for 30 min following the MAOD test . Dual-energy X-ray absorptiometry was used to measure lean body mass (LBM) and to estimate the active muscle mass (AMM) for cycling. Males achieved a significantly higher MAOD than females following correction for AMM [126.3 (5.6) versus 108.3 (6.1) ml . kg AMM(-1), P = 0.04]. The peak blood lactat e concentration ([Lac(-)]) in males [13.6 (0.9) mmol . l(-1)] was significa ntly higher than in females [10.0 (1.0) mmol l(-1)]. Males obtained a 68% h igher peak epinephrine concentration ([Epi]) than females, but the differen ce was not significant [1268 (188) pg . ml(-1) versus 755 (179) pg . ml(-1) , P = 0.066]. However, plasma [Epi] was significantly higher for males than females at 1 min [824 (116) versus 489 (116) pg . ml(-1), P = 0.036] and 3 min [330 (52) versus 179 (42) pg . ml(-1), P = 0.039] into the recovery pe riod. No gender-dependent differences in the norepinephrine concentration w ere observed at any time. Peak [Lac(-)] was significantly correlated with M AOD (ml . kg AMM(-1)) in females (r = 0.75), but not in males (r = 0.09). T he peak plasma [Epi] was not significantly correlated with MAOD (ml . kg AM M(-1)) or peak [Lac(-)] in either group. These findings suggest that there are gender-dependent differences in MAOD even when expressed relative to th e AMM for cycling. The higher blood [Lac(-)] in males compared to females o btained after supramaximal exercise was not caused by enhanced secretion of Epi. The greater MAOD in untrained males was not caused by a greater abili ty to produce Lac(-) or by enhanced secretion of Epi.