Flow motion is the periodic oscillation of blood flow in the microvascular network imparted by local and central control mechanisms. Spectral analysis of the component frequencies of the blood flow signal reveals the influence of endothelial (0.0095 – 0.02Hz), sympathetic (0.02 – 0.06Hz) and myogenic (0.06 – 0.15Hz) activity in the vessel wall and of respiration (0.15 – 0.4Hz) and heart beat (0.4 – 1.6Hz) (1). The role of flow motion to maintain microvascular perfusion and tissue homeostasis is much debated and the pathophysiological relevance of disturbed flow motion poorly understood. The simultaneous non-invasive measurement of skin blood flux (BF) and parameters of tissue oxygenation (oxyHb, deoxyHb, totalHb and SO2) using a combined laser Doppler and white light spectroscopy probe (Moor Instruments, UK) and spectral analysis over the range (0.0095 – 1.6Hz) has provided new insight into the intrinsic variability of blood flux and tissue oxygenation signals and the relationship between them (2). In healthy skin we have demonstrated a strong correlation between simultaneously recorded skin BF, tissue SO2 and total spectral power across a wide range of blood flows and multiple time varying oscillations. There is also a significant positive correlation between the contributions in each of the three low frequency bands to the BF and SO2 signals (2). However, differences in the relative contribution of the component frequencies to flow motion activity, as evidenced by a relatively small contribution of respiratory and cardiac activities to the SO2 signal, suggests a significant dissociation between the higher frequency oscillations. Exploration of the dynamic characteristics of flow motion using frequency coherence demonstrates considerable concordance within the endothelial and neurogenic (low frequency components) of the BF and SO2 signals suggesting that they are modulated in a similar manner; although causality has yet to be proven. These relationships are diminished and the intrinsic variability in flow motion signals lost in individuals with cardiovascular and metabolic disease contributing to a reduced ability to respond to changes in the local or systemic environment (3). However, our understanding of whether flow motion can be improved with therapeutic intervention is far from complete. While the concept of skin microcirculation as a peripheral index or surrogate of vascular health remains contentious, monitoring local tissue perfusion in combination with tissue oxygen parameters, could provide an early indicator of compromised tissue function and an effective tool to augment the diagnosis, treatment and management of conditions across a number of clinical specialities in which microvascular dysfunction plays a role.