Sprick Justin D, Rickards Caroline A
Institute for Cardiovascular and Metabolic Diseases, University of North Texas Health Science Center, Fort Worth, Texas.
Institute for Cardiovascular and Metabolic Diseases, University of North Texas Health Science Center, Fort Worth, Texas
Am J Physiol Regul Integr Comp Physiol. 2017 Nov 1;313(5):R507-R517. doi: 10.1152/ajpregu.00112.2017. Epub 2017 Aug 23.
Remote ischemic preconditioning (RIPC) is characterized by the cyclical application of limb blood flow restriction and reperfusion and has been shown to protect vital organs during a subsequent ischemic insult. Blood flow restriction exercise (BFRE) similarly combines bouts of blood flow restriction with low-intensity exercise and thus could potentially emulate the protection demonstrated by RIPC. One concern with BFRE, however, is the potential for an augmented rise in sympathetic outflow due to greater activation of the exercise pressor reflex. Because of the use of lower workloads, however, we hypothesized that BFRE would elicit an attenuated increase in sympathetic outflow [assessed via plasma norepinephrine (NE) and mean arterial pressure (MAP)] and middle cerebral artery velocity (MCAv) when compared with conventional exercise (CE). Fifteen subjects underwent two leg press exercise interventions: ) BFRE-220 mmHg bilateral thigh occlusion at 20% 1 rep-max (1RM), and ) CE-65% 1RM without occlusion. Each condition consisted of 4 × 5-min cycles of exercise, with 3 × 10-reps in each cycle. Five minutes of rest and reperfusion (for BFRE) followed each cycle. MAP increased with exercise ( < 0.001) and was 4-5 mmHg higher with CE versus BFRE ( ≤ 0.09). Mean MCAv also increased with exercise ( < 0.001) and was higher with CE compared with BFRE during the first bout of exercise only ( = 0.07). Plasma NE concentration increased with CE only ( < 0.001) and was higher than BFRE throughout exercise ( ≤ 0.02). The attenuated sympathetic response, combined with similar cerebrovascular responses, suggest that cyclical BFRE could be explored as an alternative to CE in the clinical setting.
远程缺血预处理（RIPC）的特点是周期性地应用肢体血流限制和再灌注，并且已被证明可在随后的缺血性损伤期间保护重要器官。血流限制运动（BFRE）同样将血流限制发作与低强度运动相结合，因此有可能模拟RIPC所显示的保护作用。然而，对BFRE的一个担忧是，由于运动加压反射的更大激活，交感神经流出可能会有更大幅度的增加。然而，由于使用了较低的工作量，我们假设与传统运动（CE）相比，BFRE会引起交感神经流出[通过血浆去甲肾上腺素（NE）和平均动脉压（MAP）评估]和大脑中动脉速度（MCAv）的增加减弱。15名受试者接受了两次腿部推举运动干预：）BFRE-双侧大腿在20%1次重复最大值（1RM）时闭塞220 mmHg，以及）CE-65%1RM不闭塞。每种情况包括4×5分钟的运动周期，每个周期3×10次重复。每个周期后休息和再灌注5分钟（用于BFRE）。MAP随运动增加（<0.001），CE时比BFRE高4-5 mmHg（≤0.09）。平均MCAv也随运动增加（<0.001），仅在第一次运动时CE比BFRE高（=0.07）。血浆NE浓度仅在CE时增加（<0.001），并且在整个运动过程中高于BFRE（≤0.02）。交感神经反应减弱，加上类似的脑血管反应，表明在临床环境中，可以探索将周期性BFRE作为CE的替代方法。
