Mechanisms of control of human skin blood flow under external pressure

This paper aims to understand human skin blood flow(SBF) response to external pressure. Alternative pressure loading by using sphygmomanometer was applied on calf while subjects sitting and lying supine respectively; the SBF was observed with laser flowmeter and wavelet analysis was carried out on the SBF signals. The main results are as follows: under pressure of 20mmHg and 40mmHg, SBF obviously increased with sitting posture while that of some subjects turned to decrease under pressure of 40mmHg when lying supine; the frequency of myogenic activity decreased under pressure. It was explained that the SBF change under pressure is the result of balance between the increase through the capillary recruitment and the decrease due to mechanical squashing of small vessels under high pressure; the turning point between increase and decrease depends on the blood pressure inside the arterioles.