Análise do padrão termográfico e do gasto energético durante o exercício aeróbio com e sem restrição de fluxo sanguíneo em sujeitos fisicamente ativos: um estudo controlado

Abstract

Introduction: Blood flow restriction (BFR) training is a method that uses low weight and restricts upper or lower blood pressure partially or completely, which can be used in aerobic exercises, with significant results in the increase of the energy expenditure (EE) in relation to the traditional training. However, it is not known what could happen with the skin temperature (ST), when using BFR during exercise. And an alternative to evaluate this phenomenon is the infrared thermography (IT), which is a non-invasive method used on sports with various purposes, such as: to analyze muscular asymmetries or a strong predictor of muscular injuries. Objective: To analyze the effects of aerobic exercises with different levels of BFR regarding EE, ST and subjective perception of distress (SPD). Method: As participants of this study there were 24 physically active males, (23,9±2,6 years old, 78,5±12,3 kg, 1,78±0,07 m, BMI = 24,7±2,4 kg/m2) without history of osteoarticular illnesses on the inferior members, that responded negatively to the PAR-Q, that performed = 150 minutes of weekly physical activity with intensity = moderate, according to the IPAQ, and that showed Ankle Brachial Index (ABI) between 0.91 and 1.30. Initially it was calculated the Body Mass Index (BMI) to ensure a homogeneous sample and the measurement of BFR of each individual before the 4 sessions of training on different levels of restriction (0, 50, 80 and 100%). Training consisted on walking on the treadmill at 40% of the subject’s maximal speed, composed by 5 series lasting 2 minutes each with 1 minute break in between, totalizing 14 minutes of testing and with a week’s gap between each session. During training, it was analyzed the EE (caloric expenditure) and the skin temperature if the subjects, by way of the IT, before, during and 24h after each training session and the SPD by way of a verbal scale. Result: The EE showed average value of 75,6±15,9; 89,7±15,8; 94,9±14,8 e 96,1±12,1 kcal to the conditions of 0, 50, 80 e 100% BFR, respectively during training. These results show a significant increase of EE on 0% BFR when comparing it to the rest (P<0.001) and between the 50 and 100% of BFR (P<0.05). However, between 50 and 80% or 80 and 100% of BFR, the EE was stable (P>0.05). The ST of MMIII did not suffer significant changes (P>0,05) immediately and 24h after the aerobic exercise, no matter what level of BFR was used (0, 50, 80 or 100%), however it was found that the temperature of the legs was higher than the thighs’ (P<0,05), the experienced SPD was higher according to the level of BFR during the exercise (P<0,001). Conclusion: The results show a gradual but non-linear increase of EE according to the rising of the BFR levels, being presented in a proportional way until the 80% BFR level and stabilizing after this plateau. Regarding TI, the results show that BFR does not influence ST neither immediately nor 24 hours after aerobic exercise, irregardless of the used BFR, while the PSE, increased as the RFS level rose during the exercise. Article attached in the Brazilian Clinical Trials Registry (REBEC) under the number RBR-3XHSJX