Factors Associated with the Effects of Continuous Pressure Stimulus to the Lower Back in the Autonomic Nerve Activity and Bowel Sounds

Abstract

We investigated the autonomic nerve activity affecting changes in bowel sounds (BS) after continuous pressure stimulation (CPS) of the lumbar region. The subjects were ten healthy young adult men. Recordings of BS were acquired from each subject using a stethoscope positioned on the left lower abdomen before and 5, 10 minutes after CPS. CPS was applied to 3.5 cm lateral from the Th12 to L2 spinous processes at 50 mmHg for 10 minutes. We then calculated the BS pressure level. Heart rate variability was also assessed using RR interval of electrocardiogram. Circulatory dynamics were measured based on blood pressure (BP). We revealed that BS power of 313 Hz increased 10 minutes after CPS was applied (BS10). The BS of 313 Hz was increased after 10 minutes in CPS. The changes in BS at 10 min after CPS directly and indirectly affected the changes in BS, LF/HF, and DBP at 5 min after CPS (CMIN = 1.214, p = 0.750, GFI = 0.941, RMSEA < 0.001). These results suggest that CPS induces intestinal peristalsis which would be effected to increased cardiac parasympathetic nerve activity and peripheral artery circulation.