Using Wavelet Analysis of Blood Flow Oscillations to Investigate Differences in Skin Blood Flow Regulations Between the Upper and Lower Limbs

Background: The objective of this study was to investigate the differences in skin blood flow regulations between the upper and lower limbs in healthy adults using wavelet analysis of skin blood oscillations. To the best of our knowledge, this is the first study investigating the dominant skin blood flow control of the upper and lower limbs in healthy adults. Methods: Skin blood flow of the forearm and leg was simultaneously measured by laser Doppler flowmetry (LDF) in 17 healthy adults. Skin blood flow oscillations were analyzed using wavelet analysis to assess the dominant control among the metabolic endothelial (0.0095-0.02 Hz), neurogenic (0.02-0.05 Hz), myogenic (0.05-0.15 Hz), respiratory (0.15-0.4 Hz), and cardiac (0.4-2 Hz) origins. Results: Skin blood flow in the leg (11.13 +/- 4.90 perfusion unit) was significantly higher than in the forearm (6.90 +/- 2.50 perfusion unit, p < 0.001). The metabolic endothelial control is more dominant in the forearm (1.19 +/- 0.51 au) compared to the leg (0.73 +/- 0.41 au, p < 0.01). The myogenic control is more dominant in the leg (1.18 +/- 0.28 au) compared to the forearm (0.96 +/- 0.18 au, p < 0.05). Conclusion: Through wavelet analysis of skin blood flow oscillations, the results indicate that metabolic endothelial control is more dominant in the forearm (upper limbs) and myogenic control is more dominant in the leg (lower limbs).