Skin capillary blood cell velocity in man. Characteristics and reproducibility of the reactive hyperemia response.

Measurements of human skin capillary blood cell velocity (CBV) were performed by videophotometric capillaroscopy using a crosscorrelation technique. Mean resting (r) CBV in a group of 64 healthy subjects (age 20-82; 33 men) was 0.60 +/- 0.51 (SD) mm/s at a skin temperature of 30.9 +/- 3.2 degrees C. Skin temperature, but not rCBV, was significantly higher in the men. rCBV showed a weak positive correlation with skin temperature with a marked increase of high rCBV values when skin temperature was more than 31 degrees C. During the postocclusive reactive hyperemia (PRH) after a one-minute arterial occlusion, CBV reached a maximal velocity of 1.17 +/- 0.66 mm/s at 7.8 +/- 2.4 s after cuff release. This PRH response was reproducible with regard to peak velocity (pCBV) and the time to pCBV. The percentage increase of CBV during PRH was inversely correlated to skin temperature (r = -0.69). The results of the present study are proposed as a basis for further studies of human skin capillary circulation in health and disease.