Introduction: High-intensity resistance exercises (RE) cause an inflammatory response that reduces functionality. Objective: To evaluate the effects of Cold Water Immersion (CWI) on leukocytosis, oxidative stress parameters, inflammatory markers and delayed onset muscle soreness (DOMS) resulting from a RE session in untrained volunteers. Methods: Thirteen volunteers (aged 26 ± 5 years) who do not engage in RE were randomized and underwent Control RE and RE with CWI sessions. Exercise sessions (leg extension machine, squats and leg presses) consisted of four sets of 10 maximum repetitions (one-week interval between the assessment and the sessions). CWI consisted of immersion in water (15°C) to the umbilicus for 10 minutes immediately after the exercise session. Complete blood count, CRP, creatine kinase (CK) and lipoperoxidation (LPO) were assessed previously (baseline) and immediately, 30 minutes and 2 hours after RE. DOMS was assessed 24 hours after the sessions. Results: RE induced progressive leukocytosis (P<0.001). CRP was elevated 2 hours after exercise (P=0.008) only in the Control RE session. CK increased 30 minutes and 2 hours after exercise (P<0.001) in the Control session, whereas in the CWI session the increase was observed after 2 hours (P<0.001). LPO increased only in the Control session after 2 hours (P=0.025). CWI reduced DOMS by 57% (P<0.001). Conclusion: CWI slows the inflammatory response and reduces DOMS in untrained individuals undergoing RE. Level of Evidence I; Randomized Clinical Trial.

ABSTRACT. This study aims to evaluate the effects of TENS at different frequencies on autonomic balance in healthy volunteers. It is a case-control study, and was composed of fourteen healthy volunteers (5 women) with 28 (3.9) years old who underwent low ) and high (100 Hz 200ms -1 ) frequency TENS. The interventions were randomized and applied for 30 minutes in the trajectory brachial nerve plexus from non-dominant member. Intensities were adjusted every 5 minutes and maintained below motor threshold. The autonomic balance was assessed before and after interventions by heart rate variability (HRV). TENS 10 Hz increased 10% sympathetic activity and decreased 10% parasympathetic activity; however, TENS 100 Hz showed opposite effects (p < 0.05). The sympatho-vagal balance increased with low frequency TENS and decreased with high frequency (p < 0.05). It can be concluded that different frequencies of TENS applied in the trajectory brachial nerve plexus modify cardiovascular autonomic responses. High frequency TENS reduces sympathetic activity and increases the parasympathetic, which favors beneficial effects on autonomic balance in healthy volunteers.Keywords: electric stimulation, autonomic nervous system, heart rate.Diferentes frequências da estimulação elétrica nervosa transcutânea no balanço simpatovagal RESUMO. Este estudo objetiva avaliar os efeitos de diferentes frequências da TENS sobre o balanço autonômico em voluntários saudáveis. Estudo caso-controle composto de quatorze voluntários saudáveis (5 mulheres), com 28 (3,9) anos de idade que foram submetidos a baixa (10 Hz 200 ms ) frequências da TENS. As intervenções foram randomizadas e aplicadas por 30 minutos sobre a trajetória do plexo nervoso braquial do membro não dominante. As intensidades foram ajustadas a cada 5 minutos e mantidas abaixo do limiar motor. O balanço autonômico foi avaliado antes e após as intervenções pela variabilidade da frequência cardíaca (VFC). TENS a 10 Hz aumentou 10% da atividade simpática e diminui 10% a atividade parassimpática, mas a TENS a 100 Hz apresentou efeitos opostos (p < 0,05). O balanço simpato-vagal aumentou com a TENS de baixa frequência e diminuiu com a alta frequência (p < 0,05). Conclui-se que as diferentes frequências da TENS aplicadas sobre a trajetória do plexo nervoso braquial modificam as respostas autonômicas cardiovasculares. A alta frequência da TENS reduz a atividade simpática e aumenta a parassimpática, o que favorece aos efeitos benéficos sobre o balanço autonômico em voluntários saudáveis.Palavras-chave: estimulação elétrica, sistema nervoso autônomo, frequência cardíaca.