Cardiorespiratory adjustments during the accentuation of respiratory sinus arrhythmia: influence from time of maneuver on minute volume, fraction of expired CO 2 , and heart rate variability
ABSTRACT Heart rate (HR) fluctuate during the respiratory cycle. This phenomenon is known as respiratory sinus arrhythmia. The deep breathing test is to keep a paced breathing in six breathing per minute and I:E relationship 1:1. The purpose of this study is to access minute volume, expired fraction of carbon dioxide (EFCO2) and autonomic control of heart rate during deep breathing test longer than 90 seconds. Sixteen young healthy male (18 - 25 years old) were assessed. The subjects were instructed to perform inspirations and expirations with duration of 10 seconds per cycle, I:E = 1:1, and consequently respiratory rate of 6 cycles per minute, for about four minutes with one minute after and before, totaling six minutes. HR was recorded beat-to-beat using a cardio frequencimeter; MV and EFCO2 was measured and recorded using a mobile ergoespirometer. To analyse statistics differences, ANOVA one way (Tuckey post-hoc) and Kruskall Wallis (Dunn post-hoc) were used (p<0.05). When deep breathing test in course, EFCO2, MV and time domain heart rate variability shows no statistics difference over time. To perform deep breathing test in young healthy male, longer than 90 seconds, can be safety, without risks of hypocapnia and no interference from EFCO2 changes in time domain heart rate variability analysis of M-RSA.