Determination of the effect of having energy drinks using laser Doppler flowmetry

In the present study, we evaluated the effect of having energy drinks using laser Doppler flowmetry technique by determining blood flow changes after having energy drinks on healthy human subjects. After having energy drinks, it is observed that the amplitude of blood perfusion signal increases. Further we have analyzed frequency response of blood perfusion signal using windowed Fast Fourier Transform. The oscillations extended over a wide frequency scale and their periods varied in time. Within the frequency range studied, 0.0095-1.6 Hz, five characteristic oscillations were revealed, arising from both local and central regulatory mechanisms e.g. endothelial/metabolic activity, sympathetic nerve activity, vascular myogenic activity, respiratory activity, and heart activity. We observed a significant change in metabolic and sympathetic nerve activity after having energy drinks. The frequency component relating metabolic and sympathetic nerve activity increase around 300% and 140% respectively. It is also observed a moderate change in myogenic and heart activity as the relative and absolute amplitude of the oscillations of this frequency interval increased around 80% in response to having energy drinks.