Affiliation:
1. Institute of Sport Sciences University of Lausanne Lausanne Switzerland
2. Department of Automation, Biocybernetics and Robotics Jožef Stefan Institute Ljubljana Slovenia
3. Faculty of Sport University of Ljubljana Ljubljana Slovenia
Abstract
AbstractPremature birth may result in specific cardiovascular responses to hypoxia and hypercapnia, that might hamper high‐altitude acclimatization. This study investigated the consequences of premature birth on baroreflex sensitivity (BRS) under hypoxic, hypobaric and hypercapnic conditions. Seventeen preterm born males (gestational age, 29 ± 1 weeks), and 17 age‐matched term born adults (40 ± 0 weeks) underwent consecutive 6‐min stages breathing different oxygen and carbon dioxide concentrations at both sea‐level and high‐altitude (3375 m). Continuous blood pressure and ventilatory parameters were recorded in normobaric normoxia (NNx), normobaric normoxic hypercapnia (NNx + CO2), hypobaric hypoxia (HHx), hypobaric normoxia (HNx), hypobaric normoxia hypercapnia (HNx + CO2), and hypobaric hypoxia with end‐tidal CO2 clamped at NNx value (HHx + clamp). BRS was assessed using the sequence method. Across all conditions, BRS was lower in term born compared to preterm (13.0 ± 7.5 vs. 21.2 ± 8.8 ms⋅mmHg−1, main group effect: p < 0.01) participants. BRS was lower in HHx compared to NNx in term born (10.5 ± 4.9 vs. 16.0 ± 6.0 ms⋅mmHg−1, p = 0.05), but not in preterm (27.3 ± 15.7 vs. 17.6 ± 8.3 ms⋅mmHg−1, p = 0.43) participants, leading to a lower BRS in HHx in term born compared to preterm (p < 0.01). In conclusion, this study reports a blunted response of BRS during acute high‐altitude exposure without any influence of changes in inspired CO2 in healthy prematurely born adults.
Funder
Javna Agencija za Raziskovalno Dejavnost RS
Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung
Subject
Physiology (medical),Physiology