Adequate skin microvascular blood flow and oxygenation are fundamental for tissue health. Detection of impairments in peripheral perfusion may allow for early diagnosis of microvascular dysfunction. Laser Doppler flowmetry (LDF) and white light spectroscopy are non-invasive techniques for measuring microcirculatory blood flux (BF) and tissue oxygenation (SO2). We have used frequency domain power spectral analysis (PSD) to investigate the relationship between the rhythmic low frequency variations in skin BF and SO2 associated with endothelial (0.0095-0.02Hz), neurogenic (0.02-0.06Hz) , myogenic (0.06-0.15Hz), respiratory (0.15-0.4Hz) and cardiogenic (0.4-1.6Hz) activity in the skin of 19 healthy individuals (31±10y; mean±SD; 8 males) before and during maximal vasodilatation induced by local warming of the skin to 43oC for 20 min. BF (arbitrary perfusion units, PU) and SO2 (%) were recorded simultaneously at the same skin site using a combined OXY+flow+temperature probe (moorCP1T-1000, Moor Instruments, Axminster UK) and data analysed using a Fourier transform and magnitude squared coherence. The relationship between BF and SO2 was described by a one-phase association (SO2=-22.8+104.2x(1-e-0.097xFlux) with an SO2 plateau of 81% for BF values >150 PU. At room temperature PSD of the respiratory and cardiac frequency bands in the SO2 signal was significantly lower than that in the BF signal. Low frequency BF and SO2 activities oscillated coherently (mean±SD, endothelial, 0.64±0.12; neurogenic, 0.60±0.18; myogenic, 0.32±0.14). However, the relative PSD contribution of the three low frequency bands to the BF and SO2 activities differed significantly (P<0.0004, paired t test) with the neurogenic component the most prominent in both BF and SO2 signals. The increase in microvascular BF and tissue SO2 during local skin warming was associated with an increase in the total spectral power of the BF signal and reduction in the total spectral power SO2 signal. The relative contribution in both BF and SO2 signals of myogenic activity was augmented and neurogenic activity reduced in vasodilated skin compared with skin at room temperature. These data demonstrate an association between a simultaneous measure of microvascular blood flux and tissue oxygenation. They suggest that there are multiple continuously varying and coherently coupled oscillations in local control mechanisms that contribute to the homeostatic regulation of skin blood flow and tissue oxygenation. KK supported by an EPSRC CASE studentship