Effects of low-intensity KAATSU resistance training on skeletal muscle size/strength and endurance capacity in patients with ischemic heart disease

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.