Abstract
The transient hypercapnic state prompted by nasal-only breathing (NB) during exercise is a compelling stimulus for enhancing cerebral blood flow (CBF). However, whether NB can serve as a chronic training modality that elicits lasting, beneficial cerebrovascular adaptations remains unclear. PURPOSE: This study assessed whether a 4-week aerobic training program incorporating NB would yield superior cerebrovascular hemodynamics during a graded exercise test (GXT) compared with training under standard, unrestricted combined breathing (CB). METHODS: Twenty-two healthy males were randomly allocated to either an NB or CB training group, performing GXTs pre- (V1) and post-intervention (V2). The training protocol constituted four weeks of supervised, moderate-intensity aerobic exercise on four non-sequential days per week. Respiratory gases were quantified using a metabolic cart, while volumetric blood flow (VBF) in the internal (ICA) and external (ECA) carotid arteries was evaluated via Doppler ultrasound. Cinematic loops were recorded and later manually analyzed with the built-in ultrasound software. Specifically, peak systolic velocity (PSV, cm/s), end diastolic velocity (EDV, cm/s), and vessel diameter (cm) within the tunica intima layer were extracted from the stored frames. A volumetric estimation of blood flow was calculated via the following equation: velocity x [π (diameter/2)2] = cm3/s. Such equation was utilized to estimate volumetric blood flow (VBF) during the peak systolic (PS) and end diastolic (ED) phases. All data was analyzed via repeated measures ANOVA with a significant set at p < 0.05. RESULTS: After the 4-week intervention (V2), the NB group showed significantly (p < 0.05) higher ICA VBF at 100% VO₂max during the PS phase (14.68 ± 0.78 cm³/s) versus the CB group (10.80 ± 0.78 cm³/s). Mechanistically, the NB group at V2 displayed a robust cardiorespiratory adaptation, marked by a normalized (V1 = 15.14 ± 3.12 mL/beat; V2 = 16.24 ± 2.55 mL/beat) oxygen pulse (a proxy for cardiac output) and a significantly (p < 0.05) higher end-tidal CO₂ (PetCO₂) throughout (V1 = 32.27 ± 2.74 mmHg; V2 = 37.62 ± 5.62 mmHg) the GXT. No differences were found in the ECA. CONCLUSION: Four weeks of aerobic training with NB stimulates enhanced cerebral perfusion during exertion. This adaptation is likely driven by a combination of an improved cardiovascular efficiency alongside recurring hypercapnic stimulus. NB during exercise appears to be a viable, non-invasive method for optimizing cerebrovascular health.
Recommended Citation
Guadiana, Marcela; Grana Gedrange, Cristina; Perez, Mia I.; Koh, Yunsuk; and Moris, Jose M.
(2026)
"Intracranial Hemodynamic Response After 4 Weeks of Aerobic Training Using Nasal Breathing,"
International Journal of Exercise Science: Conference Proceedings: Vol. 2:
Iss.
18, Article 79.
Available at:
https://digitalcommons.wku.edu/ijesab/vol2/iss18/79
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Health and Physical Education Commons, Medical Education Commons, Sports Sciences Commons