A method for evaluating vascular endothelium function in a human subject comprises monitoring changes in intensity of NADH fluorescence signal emitted from skin tissue cells of an upper limb of said subject as a function of time, wherein said changes result from reactive hyperaemia caused by blocking and releasing blood flow in the same upper limb of said subject. A system for evaluating vascular endothelium function in a human subject comprises a means for illuminating a skin on an upper limb of said subject with exciting light, a means for measuring intensity of fluorescence signal emitted from the skin and recording changes of said intensity of the fluorescence signal over time and a restriction means for blocking and releasing blood flow in the upper limb of said subject.
