THE EFFECTS OF ABDOMINAL BREATHING ON AUTONOMIC NERVOUS FUNCTION IN WOMEN \ THE RELATIONSHIP AMONG INDIVIDUAL DIFFERENCES IN AUTONOMIC NERVOUS SYSTEM ACTIVITY IN A SUPINE POSITION AT REST \ KASUMI SAKAKI Abstract We analyzed time-domain parameters (%RR50, CVRR, E/I ratio) and frequency-domain parameters (HF, LF, LF/HF, HF/SUM) from R-R interval variability to investigate the differences in autonomic nervous system activity and the effects of abdominal breathing in 20 healthy female subjects (age 48.4 }5. 5 years). The measurements were taken during spontaneous breathing in a supine position for 20 min and in a sitting position for 20 min, followed by voluntary control of abdominal breathing (expiration to inspiration time ratio was 2 to 1) for 20 min and recovery with spontaneous breathing in a sitting position for 30 min, 100 R-R intervals 16 times for 90 min and also heart rate (HR), blood pressure (BP), respiratory frequency (f) and arterial 02 and CO2 partial pressure through cutaneous (PtcO2, PtcCO2). The subjects were grouped according to the mean values of three autonomic nervous system activity parameters (%RR50, CVRR, E/I ratio) in a supine position. Group 1 (G 1) was below average for all three parameters, group 3 (G 3) was above average and group 2 (G 2) was below or above average mixed for the three parameters. A strong correlation (P< 0.01, respectively) was observed between %RR50 and HF (0.15 `0.4 Hz) during the following trials spontaneous breathing in a supine position (r=0.783) and sitting position (r=0.758), voluntary control of abdominal breathing (r=0.597), and recovery with spontaneous breathing in a sitting position (r=0.756). With regard to the characteristics of each group, the following were observed G 1 showed an accelerated trend of sympathetic nervous system activity and the approximate mean value was indicated in measurements of respiratory-circulatory system activity (HR, f, BP). G2 showed an unstable trend in which either sympathetic or parasymathetic nervous system activities were accelerated, blood pressure was higher and many respiratory frequencies were observed among the three groups. G 3 showed an accelerated trend in parasympathetic nervous system activity ; and both blood pressure and respiratory frequency were consistently low in the three groups. These results indicated that there were natural differences in each subject in autonomic nervous system activity and physiological function in a supine position at rest. It was found that voluntary control of abdominal breathing enhanced the vagal modulation of the heart rate in subjects who showed an accelerated trend of sympathetic nervous system activity. (Jpn. J. Phys. Fitness Sports Med. 2001, 50 : 105 `118) key word : heart rate variability, autonomic nervous system, vagal modulation, abdominal breathing Department of Hygiene and Public Health, Tokyo Women's Medical University, School of Medicine 8-1 Kawadacho, Sinjuku-ku, Tokyo, 162-8666, Japan
Table 1. Data from spontaneous breathing in supine, sitting positions and during volun tary control to abdominal breathing, followed by recovery with spontaneous breathing in a sitting position. Values are means (SD); Significantly different among three groups. (*P<0.05, * *P<0.01)
Fig. 1. Differences between three groups in mean %RR50, CVRR and E/Iratio which spec tral estimates are computed from R-R interval during spontaneous breathing in supine, in sitting positions and during voluntary control to abdominal breathing, fol lowed by recovery with spontaneous breathing in a sitting position. Data are mean }SD. n=7 in group 1,7 in group 2, 6 in group 3. Significantly different between two conditoins in each group. p<0.05. p<0.01
Fig. 2. Differences between three group in mean %RR50 at 10, 20 and 30 min during 30 min recovery after abdominal breathing in a sitting position. Data are mean }SD. n=7 in group 1, 7 in group 2, 6 in group 3.
Fig. 3. Changes in systolic blood pressure (SBP) and diastolic blood pressure (DBP) dur ing spontaneous breathing in supine, in sitting positions and during voluntary control to abdominal breathing, followed by recovery with spontaneous breathing in a sitting position. Data are mean }SD, n=7 in group 1, 7 in group 2, 6 in group 3. Significantly different between two conditoins in each group. p<0.05. p<0.01. p<0.001.
Fig. 4. Correlation between mean of %RR50 and mean power of high-frequency (HF) during spontaneous breathing in supine, in sitting positions and during voluntary con trol to abdominal breathing followed by recovery with spontaneous breathing in a sit ting position.
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