2005 Volume 1 Issue 2 Pages 57-64
KAATSU training is a novel method for strength training to induce muscle strength and hypertrophy. The purpose of the present study was to investigate the hemodynamic and autonomic nervous responses to the restriction of femoral blood flow by KAATSU. Ultrasonography, echocardiography and impedance cardiography were performed in ten healthy male volunteers aged 34 ± 1.5 before (pre), during and after (post) pressurization on both legs with KAATSU belts placed around proximal portion of both legs. The parameters measured were as follows; the superficial femoral arterial blood flow, left ventricular end-diastolic/systolic dimension (LVDd/LVDs), cardiac output (CO), stroke volume (SV), diameter of inferior vena cava (IVC), heart rate (HR), mean blood pressure (mBP), total peripheral resistance (TPR) and heart rate variability (HRV). The pressurization on both legs with KAATSU suppressed venous blood flow, and markedly induced pooling of blood into the legs with pressure-dependent reduction of femoral arterial blood flow. The application of 200 mmHg KAATSU decreased femoral arterial blood flow, LVDd, CO, SV and IVC significantly. HR tended to increase, and TPR increased significantly, but mBP did not change significantly. In addition, high frequency (HFRR), a marker of parasympathetic activity, decreased during KAATSU, while LFRR/HFRR, a quantitative marker of sympathetic autonomic nervous activity, increased significantly. These results indicate that the application of KAATSU on both legs induces venous pooling in the legs, and then inhibits venous return. The reduction of venous return causes a decrease of IVC diameter, cardiac size and stroke volume with an increase in TPR and LFRR/HFRR. Thus, the KAATSU training appears to become a useful method for potential countermeasure like lower body negative pressure (LBNP) against orthostatic intolerance for long-term bed rest or space flight as well as strength training to induce muscle strength and hypertrophy.