A new approach to the analysis of skin blood flow oscillations in human.

It is considered that there are six non-overlapping frequency intervals with constant boundaries. These intervals correspond to different mechanisms of skin blood flow regulation. The boundaries do not depend on functional conditions but this statement should be verified. Also it remains unclear how the oscillatory components of skin blood flow are related. Thus the study is aimed to verify statistically the boundaries of frequency intervals, to test the hypothesis that the boundaries depend on age and to search for relationships between spectral components of skin blood flow. The study involved 105 healthy volunteers aged from 20 to 65 years, which were divided into two age groups. Skin blood flow was registered with laser Doppler flowmeter (LDF). Assessments of frequency interval boundaries and relationship between the frequency oscillatory components of blood flow were conducted with histogram approach, bootstrap method and correlation analysis. New frequency interval boundaries were found. They were different in two groups. A linear correlation and frequency areas with moderate (0.5-0.7) and high (>0.7) correlation coefficients were found between spectral components of blood flow. The dependence of these correlations on the age was shown. Thus we proposed a conceptually new approach to analysis of spectral components of skin microhemodynamics and interpretation of results obtained by laser Doppler techniques. This approach is the result of the development of modern understanding of relationships between skin blood flow regulation mechanisms and spectral components of LDF signals. It allows one to have a new look at these relationships as well as demonstrates their dependence on the functional state of the organism as a whole.