Department of Health Science, Graduate School of Medicine, Kansai Medical University, 2-5-1 Shinmachi, Hirakata, Osaka, 573-1010, Japan.
Department of Rehabilitation, Nozaki Tokushukai Hospital, Daito, Japan.
Heart Vessels. 2021 Jun;36(6):766-774. doi: 10.1007/s00380-020-01757-z. Epub 2021 Jan 23.
Anaerobic threshold (AT) from cardiopulmonary exercise tests (CPX) is the standard for measuring exercise intensity among patients with cardiovascular disease in Japan. However, it remains controversial whether AT represents the safety limit for exercise intensity in patients with cardiovascular disease. The purpose of this study was to investigate cardiac rehabilitation (CR) efficacy and safety with exercise intensities above the AT and at a traditional AT in a randomized trial. The participants included 57 patients who were admitted to the outpatient CR unit with a diagnosis of acute myocardial infarction. The participants were randomly divided as follows: 25 patients in the AT group, who performed aerobic exercises with an intensity at the AT; and 32 patients in the "Over AT" group, who performed exercises at an intensity higher than the AT. The following components were measured: maximum oxygen uptake (peak VO), oxygen uptake at the AT (AT VO), increase in oxygen uptake during exercise (ΔVO/ΔWR) during the CPX, vascular endothelial function test (%FMD: the percentage of flow-mediated dilation), and isometric knee extension strength. The measurements were obtained at the start of the exercise therapy and after 2, 3, and 4 months. They were compared within and between groups, and the correlation between the rates of improvement was investigated. Peak VO, AT VO, ΔVO/ΔWR, and %FMD had significantly improved after 3 months in both groups. The isometric knee extension strength had improved in the "Over AT" group after 2 months. Interactions were observed with peak VO, ΔVO/ΔWR, and isometric knee extension strength. However, %FMD was not significantly different between the groups. In the "Over AT" group, the rate of improvement in peak VO was positively correlated with the improvement in the isometric knee extension strength (r = 0.61, p < 0.001), but not with %FMD. These data suggest that exercise at an intensity above the AT improved exercise tolerance faster than that at the AT, and this improvement rate was associated with changes in isometric knee extension strength.
无氧阈（AT）是日本心血管疾病患者测量运动强度的标准，来自心肺运动测试（CPX）。然而，AT 是否代表心血管疾病患者运动强度的安全极限仍存在争议。本研究旨在通过随机试验探讨 AT 以上和传统 AT 强度的运动对心脏康复（CR）的疗效和安全性。参与者包括 57 名因急性心肌梗死而被收入门诊 CR 病房的患者。参与者被随机分为以下两组：25 名 AT 组患者，以 AT 强度进行有氧运动；32 名“高于 AT”组患者，以高于 AT 的强度进行运动。以下指标进行了测量：最大摄氧量（peak VO）、AT 时的摄氧量（AT VO）、CPX 期间运动时摄氧量的增加（ΔVO/ΔWR）、血管内皮功能测试（%FMD：血流介导扩张的百分比）和等长膝关节伸展强度。测量在运动治疗开始时以及治疗后 2、3 和 4 个月时进行。对组内和组间进行了比较，并对改善率之间的相关性进行了调查。两组患者在治疗后 3 个月时，peak VO、AT VO、ΔVO/ΔWR 和 %FMD 均显著改善。“高于 AT”组在治疗后 2 个月时等长膝关节伸展强度也有所改善。在 peak VO、ΔVO/ΔWR 和等长膝关节伸展强度方面观察到了交互作用。但是，两组之间的 %FMD 没有显著差异。在“高于 AT”组中，peak VO 的改善率与等长膝关节伸展强度的改善率呈正相关（r=0.61，p<0.001），但与 %FMD 无关。这些数据表明，高于 AT 的强度的运动比 AT 强度的运动更快地提高运动耐量，而这种改善率与等长膝关节伸展强度的变化有关。
