The Influence of Acute Hypoxia on Oxygen Uptake and Muscle Oxygenation Kinetics During Cycling Exercise in Prepubertal Boys.
Pediatr Exerc Sci
; : 1-8, 2024 Jun 26.
Article
in En
| MEDLINE
| ID: mdl-38925533
ABSTRACT
PURPOSE:
To examine the effect of normobaric hypoxia on pulmonary oxygen uptake (VËO2) and muscle oxygenation kinetics during incremental and moderate-intensity exercise in children.METHODS:
Eight prepubertal boys (9-11 y) performed incremental cycle tests to exhaustion in both normoxia and hypoxia (fraction of inspired O2 of 15%) followed by repeat 6-minute transitions of moderate-intensity exercise in each condition over subsequent visits.RESULTS:
Maximal oxygen uptake (VËO2max) was reduced in hypoxia compared with normoxia (1.69 [0.20] vs 1.87 [0.26] L·min-1, P = .028), although the gas exchange threshold was not altered in absolute terms (P = .33) or relative to VËO2max (P = .78). During moderate-intensity exercise, the phase II VËO2 time constant (τ) was increased in hypoxia (18 [9] vs 24 [8] s, P = .025), with deoxyhemoglobin τ unchanged (17 [8] vs 16 [6], P ≥ .28).CONCLUSIONS:
In prepubertal boys, hypoxia reduced VËO2max and slowed VËO2 phase II kinetics during moderate-intensity exercise, despite unchanged deoxyhemoglobin kinetics. These data suggest an oxygen delivery dependence of VËO2max and moderate-intensity VËO2 kinetics under conditions of reduced oxygen availability in prepubertal boys.
Full text:
1
Database:
MEDLINE
Language:
En
Year:
2024
Type:
Article