KAATSU training induces muscle hypertrophy and strengthens muscle in athletes and healthy subjects through short-term and low-intensity exercise. However, it remains uninvestigated whether lowintensity KAATSU resistance training (LIKRT) induces muscle strength and hypertrophy in patients with cardiovascular diseases. We examined the effects of LIKRT on skeletal muscle size/strength and endurance capacity in patients with ischemic heart disease (IHD). Seven male patients with stable IHD performed three kinds of resistance exercises (leg press, leg curl and leg extension) with their femoral muscle blood flow restricted by KAATSU belt two times/week for three months. We measured one RM (1-RM) in each resistance exercises, and evaluated muscle cross-sectional areas (CSA) by MRI before training and after the training. We used cardiopulmonary examinations to measure endurance capacity (Peak VO2 (VO2peak), VO2 at anaerobic threshold (VO2AT)). We performed blood sampling to measure resting plasma level of insulin growth factor-1 (IGF-1) and serum high-sensitive C-reactive protein (hsCRP). LIKRT significantly increased leg press (15%), leg curl (18%) and leg extension (17%) 1-RM strength. Increases of muscle CSA in quadriceps femoris at the proximal lower leg (30%), the mid-thigh (50%), and the proximal lower leg (70%) were 5.1%, 4.6% and 10.4%, respectively. Similarly, hamstring and adductor CSA were also increased by LIKRT. LIKRT significantly increased VO2peak and VO2AT by 10.7% and 10.9%, respectively. IGF-1 and hsCRP were not altered before or after the training. These results suggest that LIKRT increases muscle strength/mass and endurance capacity in patients with IHD. LIKRT appears to be a promising and effective resistance method in cardiac rehabilitation.
Low-intensity resistance exercise with blood flow restriction (BFR), also known as "Kaatsu," causes a dramatic increase in the secretion of growth hormone. Several reports have shown that Kaatsu is effective for training in patients with stroke. However, the influence of Kaatsu training on brain function remains unclear. This study aimed to investigate the acute effects of Kaatsu training on blood flow in the brain. Six healthy male subjects performed a single-arm curl with and without BFR using 20% of the weight of 1 repetition maximum(RM); 1 set of 30 repetitions (reps) was followed by 3 sets of 15 reps, with a 30-s interval in between. During the procedure, cerebral blood flow was measured using near-infrared spectroscopy (NIRS). During arm curls with BFR, the oxygenated hemoglobin (oxy-Hb) concentration of the contralateral motor cortex increased significantly compared to that during curls without BFR. The results of this study suggest that Kaatsu training has a positive effect on the brain by increasing cerebral blood flow and that it is useful for treating diseases such as stroke and cognitive disorders caused by brain dysfunction.