Fig. 5.

Postnatal changes in V̇e/V̇co₂ ratios in normoxia and hypoxia. A: V̇e/V̇co₂ ratios in normoxia [V̇e(n)/V̇co₂(N)]. The ratio was highest at P0–P1, then reduced significantly at P2 followed by a plateau until P12. It then rose significantly at P13, followed by a gradual decline at P14-P15 and a plateau until P21. B: V̇e/V̇co₂ in hypoxia [V̇e(h)/V̇co₂(H)]. This ratio was highest at P0 and P1, but fell insignificantly at P2, followed by a relative plateau until P21. C: V̇e/V̇co₂ in hypoxia vs. that in normoxia. One-sample t-test showed that in the majority of age groups, the ratio was significantly different from 1 (P < 0.05), except for P0, P1, and P13. P13 is the only time point that shows a statistically significant difference between any adjacent 2 age groups (P < 0.05). For statistical comparisons between successive age groups, please see methods. *P < 0.05. **P < 0.01.