The KAATSU training is a novel method for muscle training performed under the reduction of muscle blood flow by a specially-designed belt (KAATSU belt). Under the conditions of restricted muscle blood flow, even short-term, low-intensity exercise such as walk training can induce muscle strength, and increased muscle mass (Takarada et al. 2000a; b; c; Takarada et al., 2002a,b; Abe et al. 2006). In addition, KAATSU femoral blood flow restriction induces lower-body venous pooling and reduces venous return (Takano et al., 2006), resulting in stimulating cardiovascular effects of orthostasis in 1G like lower body negative pressure (LBNP) (Iida et al., 2007). Since the most effective countermeasure regimen to prevent cardiovascular deconditioning in space flight would be a gravitation-like stress combined with exercises, the use of KAATSU in combination with low-intensity resistance exercise would provide a significant countermeasure like LBNP for space flight countering both cardiovascular and musculoskeletal decline. Thus, the KAATSU training may be a promising training in astronauts to prevent cardiovascular deconditioning and muscle atrophy in space flights (Iida et al., 2006) as well as athletes and healthy persons as described previously (Nakajima et al., 2006). Haemostasis is achieved through a delicate equilibrium between the coagulation and fibrinolytic cascades (Wu and Thiagarajan, 1996). Exercises have been shown to affect activation of both the coagulation and fibrinolytic cascades (Davis et al., 1976; Andrew et al., 1986; Boman et al., 1994; Weiss et al., 1998; El-Sayed et al., 2000; Ribeiro et al., 2006). Regular exercise preferentially activates fibrinolysis, which is generally associated with favorable alterations in risk from cardiovascular morbidity, while strenuous exercise may increase blood coagulation, and promote thrombus formation (Hilberg et al., 2002), resulting in exertion-related ischemic events (Giri et al., 1999). Thus, it is likely that effects of exercise on the haemostatis are Effects of KAATSU training on haemostasis in healthy subjects