The purpose of this study was to determine if differences in oxygen uptake kinetics and oxygen deficit existed between normal weight and severely overweight adolescent girls. Subjects included 10 normal weight and 8 severely overweight girls. The participants performed a leg cycling VO2 peak test and a constant load leg cycling test at 80% of the ventilatory threshold (T-vent). In the constant workload test O2 kinetics as indicated by Phase I (VO2 L at 20 sec) and Phase II time constants (t) were determined. Also, the O2 deficit (VO2 L) was measured. As expected significant differences were noted in body composition and VO2 peak relative to mass with normal weight body mass averaging 55.3 ± 7.0 kg, severely overweight 90.5 ± 18.0 kg, % fat normal weight 27.3 ± 3.9%, severely overweight 49.7 ± 4.9% and VO2 peak (ml·kg(-1)·min(-1)) normal weight 32.0 ± 2.7 and severely overweight 22.0 ± 5.3. VO2 peak (l·min(-1)) and T-vent (%VO2 max) were similar between groups. Results revealed similar O2 kinetic responses between groups; phase I kinetics normal weight 0.72 ± 0.15 L; severely overweight 0.75 ± 0.13L, phase II (t) normal weight 41.5 ± 21.3 sec; severely overweight 33.9 ± 22.7 sec. However, the O2 deficit was significantly higher in the severely overweight (0.75 ± 0.15L) when compared to the normal weight group (0.34 ± 0.13L). Correlations ranged from r = -0.15 to 0.51 between VO2 peak (L·min(-1)) or fat weight and phase I, t and O2 deficit. These data generally support previous research concerning the independence of O2 uptake response and body size. Key PointsVO2 (L·min(-1) ) similar between the severely overweight and normal weight female youthPhase I and II O2 kinetic responses similar between severely overweight and normal weight female youthO2 deficit was significantly greater in the severely overweight participants.
Keywords: O2 deficit; O2 kinetics; female; severely overweight; youth.