The Effect Of Paced Nasal Breathing On Central And Cerebrovascular Hemodynamics Among Young Adults

PURPOSE: Somatic practices (e.g., yoga, Pilates) have increased public interest in breathing patterns, which can influence cardiovascular and cerebrovascular health. We previously found that paced nasal breathing improved heart rate variability metrics and lowered peripheral diastolic blood pressure (BP). However, how breathing patterns affect central BP and cerebrovascular function is still unclear. Therefore, we tested the hypothesis that paced nasal breathing, compared to paced oral breathing, would acutely lower central diastolic BP and improve cerebrovascular metrics. METHODS: We tested 19 adults in this study (17 females; age: 24[5] years; body mass index: 22 ± 2 kg•m-2.; screening brachial BP: 107 ± 9/65 ± 7 mmHg; presented as median[IQR] or mean ± SD). We paced participants’ respiratory rates during nasal and oral breathing (random order, 5 min each) using a metronome set to their average spontaneous respiratory rate (11 ± 3 breaths/min). We compared brachial and central BP (automated oscillometric measurement; SphygmoCor XCEL) and right middle cerebral artery blood velocity (MCAv; Multigon 9D) between conditions using paired, two-tailed t-tests for normally distributed data (presented as mean ± SD). We quantified effect sizes using Cohen’s d. RESULTS: As expected, we found that peripheral diastolic BP was lower during nasal breathing (nasal: 63 ± 7 vs. oral: 66 ± 7 mmHg, p < 0.01, d = 0.74). Additionally, central mean BP (nasal: 77 ± 8 vs. oral: 79 ± 9 mmHg, p = 0.03, d = 0.54) and central diastolic BP (nasal: 65 ± 7 vs. oral: 67 ± 8 mmHg, p < 0.01, d = 0.82) were lower with nasal breathing. Pulsatility index was higher during nasal breathing (peak MCAv-nadir MCAv/mean MCAv; nasal: 1.02 ± 0.16 vs. mouth: 0.97 ± 0.16 mmHg, p = 0.03, d = 0.54). Mean MCAv was not different between conditions (nose: 47 ± 10 vs. oral: 49 ± 12 cm/s, p = 0.20, d = 0.30). Central systolic BP, augmentation index, subendocardial viability ratio, and cerebrovascular conductance index (mean MCAv/central mean BP) were not different between conditions (p > 0.16). CONCLUSIONS: These findings suggest that paced nasal breathing acutely lowers central mean and diastolic BP, as well as increases pulsatility index values compared with oral breathing among healthy young adults. Supported by: JCW was supported by the National Institutes of Health (K01HL160772) and the American Heart Association (23CDA1037938).