Suprasystolic limb occlusion (SLO) is an important manoeuvre for blood pressure measurement, being also used as a challenge for the assessment of endothelial activity. It is commonly carried out by inflating a pneumatic pressure cuff above systolic pressure for a certain period of time. Although very useful, the magnitude and duration of occlusion are critical experimental aspects because of the mild discomfort it may cause to the subject. This perceived discomfort is likely to increase the activity of sympathetic nervous system and to have a systemic impact in hemodynamics. This study aims to further expand the knowledge on the physiological response to SLO by exploring the dynamics of autonomic regulation. Ten healthy male subjects (mean 20.2 ± 2.3 y.o.) participated in this study after giving informed written consent. After acclimatization, subjects performed a standard SLO protocol on a random upper limb while sitting upright, as follows: 10 min resting with both arms at heart level, 5 min arm occlusion (200 mmHg) and 10 min recovery in the initial position. Photoplethysmography (PPG) signals were acquired from the second finger of the occluded and non-occluded arms, with the latter being used for pulse rate variability (PRV) analysis, a surrogate of the well-known heart rate variability (HRV). The power of the high (HF), low (LF) and very low frequency components of the PPG signals were determined in all phases, as well as the LF/HF ratio. The electrodermal activity (EDA) was also acquired from the third and fourth fingers of both hands. The PPG and EDA signals were then decomposed with the wavelet transform in order to obtain their frequency spectra. During occlusion a significant decrease in the LF/HF ratio was noted, suggesting a decrease in cardiac sympathetic activity. In contrast, a significant increase in EDA was noted in both hands, suggesting an increase in cutaneous sympathetic activity. Also noteworthy, the EDA signals resembled one another very closely during the entire procedure, showing that the mechanical compression of the arm did not affect the magnitude of the signals. The spectral organization of the PPG signals has already been proposed two contain several components – cardiac, respiratory, myogenic, sympathetic, endothelial NO-dependent and endothelial NO-independent. The spectra of the EDA signals revealed a high frequency component that was aligned with the PPG cardiac component, together with several low frequency components which were only partially aligned with the sympathetic PPG component. These results suggest that the autonomic response to a SLO manoeuvre is complex and probably organ-dependent. This complexity is apparent from the EDA signal spectra, whose usefulness should be better investigated in the future.