Cardiorespiratory Responses of Adults and Children during Normoxic and Hypoxic Exercise

Kapus, Jernej; Mekjavic, Igor B.; McDonnell, Adam C.; Ušaj, Anton; Vodičar, Janez; Najdenov, Peter; Jakovljević, Miroljub; Mekjavič, Polona Jaki; Žvan, Milan; Debevec, Tadej

doi:10.1055/s-0043-109376

Cited by 4 publications

(4 citation statements)

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“…First, the variability in several outcome measures was relatively high, so similarities between groups may be due to a lack of statistical power in those comparisons. However, our previous work in children cohorts [30,31] suggested that this study was sufficiently powered to detect differences in exercise capacity. Furthermore, participants with BPD were excluded from the study which, while allowing an investigation of prematurity per se, may underestimate the effect of pre-term birth in relation to the entire population.…”

Section: Discussionmentioning

confidence: 93%

Effects of Pre-Term Birth on the Cardio-Respiratory Responses to Hypoxic Exercise in Children

Narang

Manferdelli

Kepic

et al. 2022

Life

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Pre-term birth is associated with numerous cardio-respiratory sequelae in children. Whether these impairments impact the responses to exercise in normoxia or hypoxia remains to be established. Fourteen prematurely-born (PREM) (Mean ± SD; gestational age 29 ± 2 weeks; age 9.5 ± 0.3 years), and 15 full-term children (CONT) (gestational age 39 ± 1 weeks; age 9.7 ± 0.9 years), underwent incremental exercise tests to exhaustion in normoxia (FiO2 = 20.9%) and normobaric hypoxia (FiO2 = 13.2%) on a cycle ergometer. Cardio-respiratory variables were measured throughout. Peak power output was higher in normoxia than hypoxia (103 ± 17 vs. 77 ± 18 W; p < 0.001), with no difference between CONT and PREM (94 ± 23 vs. 86 ± 19 W; p = 0.154). V̇O2peak was higher in normoxia than hypoxia in CONT (50.8 ± 7.2 vs. 43.8 ± 9.9 mL·kg−1·min−1; p < 0.001) but not in PREM (48.1 ± 7.5 vs. 45.0 ± 6.8 mL·kg−1·min−1; p = 0.137; interaction p = 0.044). Higher peak heart rate (187 ± 11 vs. 180 ± 10 bpm; p = 0.005) and lower stroke volume (72 ± 13 vs. 77 ± 14 mL; p = 0.004) were observed in normoxia versus hypoxia in CONT, with no such differences in PREM (p = 0.218 and > 0.999, respectively). In conclusion, premature birth does not appear to exacerbate the negative effect of hypoxia on exercise capacity in children. Further research is warranted to identify whether prematurity elicits a protective effect, and to clarify the potential underlying mechanisms.

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Section: Discussionmentioning

confidence: 93%

Effects of Pre-Term Birth on the Cardio-Respiratory Responses to Hypoxic Exercise in Children

Narang

Manferdelli

Kepic

et al. 2022

Life

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“…The present study was part of a bigger research project investigating potential differential effects of exercise and hypoxia on various physiological responses in adults and children. A detailed outline of the project along with some of the results has been published previously (Kapus et al, 2017). The participants arrived at the experimental facility, situated at an altitude of 940 m (Planica Olympic centre, Rateče, Slovenia) 1 day prior to the start of the tests.…”

Section: Methodsmentioning

confidence: 99%

Muscle Oxygenation During Hypoxic Exercise in Children and Adults

Ušaj

Kapus

et al. 2019

Front. Physiol.

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IntroductionWhile hypoxia is known to decrease peak oxygen uptake (V.⁢o2 max) and maximal power output in both adults and children its influence on submaximal exercise cardiorespiratory and, especially, muscle oxygenation responses remains unclear.MethodsEight pre-pubertal boys (age = 8 ± 2 years.; body mass (BM) = 29 ± 7 kg) and seven adult males (age = 39 ± 4 years.; BM = 80 ± 8 kg) underwent graded exercise tests in both normoxic (PiO2 = 134 ± 0.4 mmHg) and hypoxic (PiO2 = 105 ± 0.6 mmHg) condition. Continuous breath-by-breath gas exchange and near infrared spectroscopy measurements, to assess the vastus lateralis oxygenation, were performed during both tests. The gas exchange threshold (GET) and muscle oxygenation thresholds were subsequently determined for both groups in both conditions.ResultsIn both groups, hypoxia did not significantly alter either GET or the corresponding V.⁢o2 at GET. In adults, higher trueV.E levels were observed in hypoxia (45 ± 6 l/min) compared to normoxia (36 ± 6 l/min, p < 0.05) at intensities above GET. In contrast, in children both the hypoxic trueV.E and V.⁢o2 responses were significantly greater than those observed in normoxia only at intensities below GET (p < 0.01 for trueV.E and p < 0.05 for V.⁢o2). Higher exercise-related heart rate (HR) levels in hypoxia, compared to normoxia, were only noted in adults (p < 0.01). Interestingly, hypoxia per se did not influence the muscle oxygenation thresholds during exercise in neither group. However, and in contrast to adults, the children exhibited significantly higher total hemoglobin concentration during hypoxic as compared to normoxic exercise (tHb) at lower exercise intensities (30 and 60 W, p = 0.01).ConclusionThese results suggest that in adults, hypoxia augments exercise ventilation at intensities above GET and might also maintain muscle blood oxygenation via increased HR. On the other hand, children exhibit a greater change of muscle blood perfusion, oxygen uptake as well as ventilation at exercise intensities below GET.

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“…Early work on hypoxic exercise-related differences between children and adults [ 17 , 18 ] did not elucidate any specific differences. Further, the data obtained by Kriemler and colleagues [ 10 ] during short term terrestrial altitude or our previous work in normobaric hypoxia [ 9 ] did not suggest any specific differential ventilatory responses in children. However, two important age-specific factors should be considered when assessing ventilatory responses to hypoxic exercise.…”

Section: Introductionmentioning

confidence: 54%

“…While hypoxia is known to reduce exercise capacity in all individuals [ 7 , 8 ], the effects of maturation/ageing on physiological responses during hypoxic exercise remain poorly investigated. Indeed, very few studies to date have investigated physiological responses to hypoxic exercise in children [ 9 , 10 , 11 ].…”

Section: Introductionmentioning

confidence: 99%

Cardio-Respiratory and Muscle Oxygenation Responses to Submaximal and Maximal Exercise in Normobaric Hypoxia: Comparison between Children and Adults

Ušaj

Sotiridis

Debevec

2023

Biology

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As differential physiological responses to hypoxic exercise between adults and children remain poorly understood, we aimed to comprehensively characterise cardiorespiratory and muscle oxygenation responses to submaximal and maximal exercise in normobaric hypoxia between the two groups. Following familiarisation, fifteen children (Age = 9 ± 1 years) and fifteen adults (Age = 22 ± 2 years) completed two graded cycling exercise sessions to exhaustion in a randomized and single-blind manner in normoxia (NOR; FiO2 = 20.9) and normobaric hypoxia (HYP; FiO2 = 13.0) exercises conditions. Age-specific workload increments were 25 W·3 min−1 for children and 40 W·3 min−1 for adults. Gas exchange and vastus lateralis oxygenation parameters were measured continuously via metabolic cart and near-infrared spectroscopy, respectively. Hypoxia provoked significant decreases in maximal power output PMAX (children = 29%; adults 16% (F = 39.3; p < 0.01)) and power output at the gas exchange threshold (children = 10%; adults:18% (F = 8.08; p = 0.01)) in both groups. Comparable changes were noted in most respiratory and gas exchange parameters at similar power outputs between groups. Children, however, demonstrated, lower PETCO2 throughout the test at similar power outputs and during the maintenance of V˙CO2 at the maximal power output. These data indicate that, while most cardiorespiratory responses to acute hypoxic exercise are comparable between children and adults, there exist age-related differential responses in select respiratory and muscle oxygenation parameters.

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Cardiorespiratory Responses of Adults and Children during Normoxic and Hypoxic Exercise

Cited by 4 publications

References 52 publications

Effects of Pre-Term Birth on the Cardio-Respiratory Responses to Hypoxic Exercise in Children

Effects of Pre-Term Birth on the Cardio-Respiratory Responses to Hypoxic Exercise in Children

Muscle Oxygenation During Hypoxic Exercise in Children and Adults

Cardio-Respiratory and Muscle Oxygenation Responses to Submaximal and Maximal Exercise in Normobaric Hypoxia: Comparison between Children and Adults

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