Abstract
The purpose of this study was to clarify the changes in the rectal pressure and the circulatory system between sitting and supine positions in defecation with taking pressure.
Twelve healthy volunteers (age 22 ± 2 years) consented to participate in this study. They performed ①the maximal pressure into the abdomen, ②the rectal pressure at 20 mmHg in supine and sitting positions for each 15 sec in the end of inspiration. The intrarectal pressure (RP), blood pressure (BP), heart rate (HR) and muscle activity were recorded continuously with Intercross330.
In the maximal pressure into the abdomen, RP was higher in sitting than supine (sitting vs supine: 33.0±10.3 vs 23.6±7.7 mmHg, p=0.010).The change in BP was greater in sitting than supine (sitting vs supine: 54.2±24.5 vs 28.2±10.1 mmHg, p=0.003). In the rectal pressure at 20 mmHg, there were no significant changes in BP.
In conclusion, when straining pressure, RP becomes higher in sitting position than supine. It's easier to defecate in a sitting position, because the strain is transmitted in the rectum effectively. There were not significant between the two postures in the change of BP on the same RP in defecation.
