OBJECTIVE: To identify the variation of sensory perception and motor response in the different phases of the menstrual cycle. METHOD: Thirty women aged 18 to 40 years old (23.7 ± 3.60), with body mass index between 18.5 and 25kg/m² (21.15 ± 2.32) and menstrual cycle of 21-35 days, participated in this study. A pulse generator was used, with pulsed electric current frequency of 50Hz and variable phases of 20 (L20), 50 (L50), 100 (L100), 300 (L300), 500 (L500), 1000 (L1000) and 3000µs (L3000). The threshold of sensory perception (TSP) was identified as the first sensation of increased current intensity and the threshold of motor response (TMR) as the minimum muscle contraction detected. Five collections were done, at each of the following phases: phase 1- menstrual (P1), phase 2- follicular (P2), phase 3- ovulatory (P3), phase 4- luteal (P4) and phase 5- premenstrual (P5). The data analysis consisted of the Friedman test followed by the Rank test, carried out in the BioStat 4.0® software, with a significance level of 5%. RESULTS: The TSP was lower in P5 than in the other menstrual phases, for the L20, L300, L500, L1000 and L3000 currents. For the TMR, there was difference in the L20, L50, L500 and L1000 currents between P5 and all other phases; in the L100 current, between P1 and P5; and in the L300 and L3000 currents for P1, P2 and P3 versus P5. CONCLUSIONS: The thresholds of sensory perception and motor response varied systematically through the phases of the menstrual cycle, thus influencing motor-sensory behavior.
menstrual cycle; estrogen; progesterone; electrical stimulation of transcutaneous nerves
