The effect of short acting hyperoxia on heart rate and blood pressure variability in hypertensive and normotensive individuals

Abstract

Background Previous studies have shown that hyperoxia- induced deactivation of carotid body chemoreceptors produces transient decrease in systolic and mean blood pressure and reduces sympathetic activation measured by microneurography. This study compares the effect of acute hyperoxia on blood pressure and heart rate variability between hypertensive and normotensive subjects.

Material and methods Ten males with hypertension (age 39.1 ± 2.9 yrs.; BMI 27.6 ± 1.0 kg/m2) and 11 normotensives males (age 39.7 ± 2.7 yrs.; BMI 26.1 ± 1.0 kg/m2) received, via non-rebreathing mask ventilation, ambient air followed by 100% oxygen for 10 minutes. The blood pressure variability, heart rate variability, blood pressure respiratory rate, and oxygen saturation were recorded continuously.

Results Ventilation with 100% oxygen resulted in the decrease in total power density of systolic and diastolic blood pressure variability (PSD-dBP, PSD-sBP) and low frequency bands (LF-dBP i LF-sBP) in hypertensive patients. No changes were noted in ratio of low and high frequency bands (LF/HF) and in parameters of heart rate variability (HRV) in both groups.

Conclusions Results of the study indicate that deactivation of carotid bodies with hyperoxia decreases sympathetic activity measured using blood pressure variability method.