Simões Rodrigo P, Mendes Renata G, Castello-Simões Viviane, Catai Aparecida M, Arena Ross, Borghi-Silva Audrey
Cardiopulmonary Physical Therapy Laboratory, Department of Physical Therapy, Federal University of Sao Carlos , Sao Carlos - Sao Paulo, Brazil.
Department of Physical Therapy and Integrative Physiology Laboratory - College of Applied Health Sciences, University of Illinois at Chicago , Chicago, Illinois, USA.
J Sports Sci Med. 2016 Dec 1;15(4):649-657. eCollection 2016 Dec.
The aim of this study was to investigate whether it is possible to identify the first turn point of blood lactate (BL) concentration (1 lactate threshold - LT1) during a discontinuous resistance exercise protocol in coronary artery disease (CAD) patients and verify if heart rate variability (HRV) responses are consistent with BL responses. A total of 22 elderly men, 12 with CAD and 10 apparently healthy (control group = CG), underwent one-repetition maximum (1RM) testing on an inclined leg press. Discontinuous resistance exercise testing (DRET) was initiated at 10% of the 1RM with subsequent increases of 10% until 30% and after this percentage, 5% increments of 1RM was carried out. The load corresponding to LT1 was approximately 30% 1RM in both groups; and the LT1 estimate by HRV was associated with BL responses. HRV indices representing parasympathetic modulation decreased with increasing loads until LT1 and stabilized thereafter in both groups, and HRV indices representing sympathetic and parasympathetic modulations only increased in the CAD group from 30% 1RM with higher values after this load in relation to the CG. We conclude HRV appears to be an effective tool to estimate the LT1 during discontinuous resistance exercise in patients with CAD. In addition, these results may have an impact on the prescription of endurance resistance exercise in the CAD population, as cardiac vagal modulation is an important indicator of cardiovascular protection and the over-activity of sympathetic modulation is related to cardiovascular risk.
本研究的目的是调查在冠心病（CAD）患者的间断性抗阻运动方案中，是否有可能识别出血乳酸（BL）浓度的第一个转折点（1乳酸阈值-LT1），并验证心率变异性（HRV）反应是否与BL反应一致。共有22名老年男性，其中12名患有CAD，10名明显健康（对照组=CG），在斜腿推举机上进行了一次重复最大值（1RM）测试。间断性抗阻运动测试（DRET）从1RM的10%开始，随后每次增加10%，直至30%，在此百分比之后，以1RM的5%递增。两组中对应于LT1的负荷约为1RM的30%；通过HRV估计的LT1与BL反应相关。代表副交感神经调节的HRV指标在两组中均随着负荷增加直至LT1而下降，此后稳定下来，而代表交感神经和副交感神经调节的HRV指标仅在CAD组中从1RM的30%开始增加，在此负荷之后的值高于CG组。我们得出结论，HRV似乎是估计CAD患者间断性抗阻运动期间LT1的有效工具。此外，这些结果可能会对CAD人群的耐力抗阻运动处方产生影响，因为心脏迷走神经调节是心血管保护的重要指标，而交感神经调节的过度活跃与心血管风险相关。
