General characteristics of the population and experimental conditions during protocol 1 and protocol 2.

BMI means Body mass index; bpm means beat per minute. Protocol 1 corresponds to ACh iontophoresis with a single current stimulation (0.1 mA, 30 s). Protocol 2 corresponds to ACh iontophoresis with a multiple current stimulations (four stimulations of 0.1 mA, 10 s with a 2 minute free interval). Protocol 1 and 2 were performed on separated days. Laser head distance was the distance between the laser speckle head and the skin. P means p value. NS means non significant.