Enhanced endothelial activity reflected in cutaneous blood flow oscillations of athletes

Functional alterations of vascular endothelial cells may be evaluated by analysing differences in effects of endothelium-dependent [acetylcholine (ACh)] and endothelium-independent [sodium nitroprusside (SNP)] vasodilators. We evaluated whether a dynamic approach using spectral analysis of the blood flow signal, resulting from the cutaneous red cell flux and recorded by the technique of laser Doppler flowmetry (LDF), can detect higher endothelial responsiveness in trained versus less trained individuals. There was a 1.6 times higher ACh-induced cutaneous perfusion in athletes than in controls ( P<0.05), both when evaluated as a mean value of the LDF signal or as the amplitudes of its spectral components. In the frequency interval from 0.009 to 1.6 Hz, ACh induced a 1.6 times higher average spectral amplitude ( P<0.01) in athletes compared with controls. ACh also induced a 1.6 times higher absolute spectral amplitude of the oscillator at around 0.01 Hz ( P<0.05) in the athletes compared with the controls, whereas the endothelial oscillation at around 0.01 Hz during basal unstimulated perfusion was 1.5 times higher ( P<0.01). There were no significant differences in absolute or relative amplitude during iontophoresis with SNP. These results indicate that athletes have higher endothelial activity than less trained individuals.