Cerebrovascular and respiratory adaptations following 4 weeks of transient hypercapnic aerobic exercise.

Background: Utilizing nasal breathing (NB) during a moderate-intensity aerobic exercise bout can elicit a hypercapnic insult that increases cerebral blood flow (CBF) and oxygen mobilization. Therefore, NB may bestow unique cerebrovascular and pulmonary adaptations. Aims: To examine if utilizing NB over 4 weeks of aerobic exercise provides superior cerebrovascular and respiratory adaptations than oronasal combined breathing (CB). Methods: 22 males (age: 21.55 ± 2.58 years) were randomly assigned (N = 11 per group) to either a CB or NB group. At visit 1 (V1, pre-study), pulmonary function was assessed [forced vital capacity (FVC), forced expiratory volume during the first second (FEV1.0), and peak expiratory flow (PEF)] alongside a graded maximal aerobic exercise test (GXT). After 4 weeks of moderate-intensity aerobic excise with their assigned breathing condition, variables were reassessed at visit 2 (V2, post-study). Pulmonary function was assessed via spirometry, and respiratory parameters were assessed via a metabolic cart. Ultrasound sonography was utilized to assess peak-systolic (PSV) and end-diastolic velocity (EDV) of the internal (ICA) and external (ECA) carotid artery. Multivariate models and mixed between-within repeated measures ANOVAs with Bonferroni corrections were utilized to analyze all data with a significance set at p < 0.05. Results: During the V2 GXT, the ICA PSV was significantly higher (p = 0.023) in the NB (71.05 ± 3.70 cm/s) group than the CB (56.00 ± 3.71 cm/s) group at 100% of VO2max. Similarly, the ICA EDV was significantly higher (p = 0.017) in the NB (17.69 ± 1.49 cm/s) group than the CB (11.30 ± 1.50 cm/s) group at 100% of VO2max. From V1 to V2, the NB group (p = 0.033) significantly improved FEV1.0 (V1: 4.33 ± 0.64 L; V2: 4.47 ± 0.67 L), while the CB group (p = 0.038) improved PEF (V1: 543.55 ± 96.41 L·min-1; V2: 588.77 ± 66.86 L·min-1). Conclusion: After 4 weeks of moderate-intensity aerobic exercise utilizing NB, our results suggest that the primary cerebrovascular adaptation achieved was related to a reduction in cerebrovascular resistance. Additionally, aerobic exercise training with NB displayed signs of greater alveolar elasticity.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Doctoral

Grantor

Baylor University.

Year dc:date.issued

2024

Author dc:creator

• Seiba Moris, Jose M., 1995-

Advisor dc:contributor.advisor

• Koh, Yunsuk.

• Oxygen uptake.
• Hypoventilation.
• Hyperemia.
• Partial pressure of end‑tidal CO2 (PetCO2)
• Airway resistance.
• Cognition.

Statement dc:rights

• Baylor University works are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. Contact libraryquestions@baylor.edu for inquiries about permission.

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/2104/13105

OAI identifier oai:identifier

oai:baylor-ir.tdl.org:2104/13105