Cardiorespiratory Responses of Adults and Children during Normoxic and Hypoxic Exercise

• Published in: International journal of sports medicine Vol. 38; no. 8; p. 627
• Main Authors: Kapus, Jernej, Mekjavic, Igor B, McDonnell, Adam C, Ušaj, Anton, Vodičar, Janez, Najdenov, Peter, Jakovljević, Miroljub, Jaki Mekjavić, Polona, Žvan, Milan, Debevec, Tadej
• Format: Journal Article
• Language: English
• Published: Germany 01.07.2017
• Subjects: Acclimatization; Adult; Bicycling - physiology; Child; Exercise - physiology; Exercise Test; Female; Heart Rate; Humans; Hypoxia - physiopathology; Male; Muscle Strength; Oxygen Consumption - physiology; Skiing - physiology
• ISSN: 1439-3964
• DOI: 10.1055/s-0043-109376

We aimed to elucidate potential differential effects of hypoxia on cardiorespiratory responses during submaximal cycling and simulated skiing exercise between adults and pre-pubertal children. Healthy, low-altitude residents (adults, N=13, Age=40±4yrs.; children, N=13, age=8±2yrs.) were tested in normoxia (Nor: P O =134±0.4 mmHg; 940 m) and normobaric hypoxia (Hyp: P O =105±0.6 mmHg; ~3 000 m) following an overnight hypoxic acclimation (≥12-hrs). On both days, the participants underwent a graded cycling test and a simulated skiing protocol. Minute ventilation (V ), oxygen uptake (VO ), heart rate (HR) and capillary-oxygen saturation (SpO ) were measured throughout both tests. The cycling data were interpolated for 2 relative workload levels (1 W·kg & 2 W·kg ). Higher resting HR in hypoxia, compared to normoxia was only noted in children (Nor:78±17; Hyp:89±17 beats·min ; p<0.05), while SpO was significantly lower in hypoxia (Nor:97±1%; Hyp:91±2%; p<0.01) with no between-group differences. The V , VO and HR responses were higher during hypoxic compared to normoxic cycling test in both groups (p<0.05). Except for greater HR during hypoxic compared to normoxic skiing in children (Nor:155±19; Hyp:167±13 (beats·min ); p<0.05), no other significant between-group differences were noted during the cycling and skiing protocols. In summary, these data suggest similar cardiorespiratory responses to submaximal hypoxic cycling and simulated skiing in adults and children.