Efeitos do treinamento de força com restrição do fluxo sanguíneo sobre a composição corporal, força muscular, função endotelial, biomarcadores de inflamação, de estresse oxidativo e de hipertrofia muscular e modulação autonômica de idosos

Abstract

The purpose this study was to compare the effects of LI training with and without RFS and high intensity ST without BFR on body composition, muscle strength, endothelial function, inflammatory biomarkers, oxidative stress, muscle hypertrophy and autonomic modulation in older adults. Thirty-two elderly, mean age, 72 ± 7 years, sedentary for six months, were divided in three groups as follows: CON exercise intensity set at 30 % of 1 maximum repetition (RM) without BFR; HI exercise intensity set at 70 % of 1RM without BFR; BFR exercise intensity set at 30 % of 1 RM with BFR promoted by a pressure cuff inflated 50 % of the resting systolic blood pressure. All subjects were performed a sequence of two exercises for upper limbs and two for lower limbs three days a week, 50 minutes each session, for three months. The resistance exercise was composed by three sets of 10 RM with one minute of resting between sets. All subjects were tested before and after intervention and included the following tests: body composition by dual energy x-ray absorptiometry, hand grip strength (HGS), isokinetic dynamometer, vasoreactivity analysis by venous occlusion plethysmography, microvascular morphological and function by nailfold videocapillaroscopy and plasma concentrations of inflammatory markers c-reactive protein (CRP), tumoral necrosis factor alpha (TNF-α), interleukin-6 (IL-6), soluble vascular cell adhesion molecules (sVCAM-1), soluble intercellular adhesion molecules (sICAM-1) and endothelin-1 (ET-1), oxidative stress oxidized low densitylipoprotein (oxLDL) and muscular hypertrophy insulin-like growth factor I (IGF-1) and heart rate variability (HRV). The appendicular skeletal muscle mass, HGS and peak torque increased in HI and BFR. The forearm blood flow (FBF) in post occlusion hyperemia reactive increased in CON, HI and BFR, but not of FBF after sublingual spray of nitroglycerine. The functional capillary density and capillary diameter afferent, apical and efferent did not change in all groups. The increment of red blood cell velocity compared to rest condition increased in HI and BFR and the time taken to reach maximal red blood cell velocity decreased in BFR, did not change in HI. No significant differences were observed in TNF-α, IL-6, sVCAM-1, ET-1 and oxLDL in the study groups after intervention. The usCRP increased in HI and the sICAM-1 decreased in BFR. The IGF-1 decreased in CON, no significant diference in AI and increased in RFS. There were no changes in the HRV indexes, time domain and frequency domain in all groups. The strength training with BFR program was able to improve lean mass and muscle strength as well endothelial function without causing increased inflammation and oxidative stress.