Fig. 4
From: Paced breathing causes tonic change rather than phasic modulation of superficial venous diameter
Ensemble average of the respiratory modulation of vein diameter. Fifty-second recordings of vein diameter averaged over 21 participants. The three panels show the results for SB, 3 s-PB, and 10 s-PB, respectively. The upper trace (solid line) in each panel indicates the vein diameter, and the lower trace (dashed line) shows the respiration. Error bars represent standard deviations (SDs)