Low-intensity Resistance Exercise with Blood Flow Restriction Does Not Activate Coagulation System in Young Men

Abstract

It has been shown in recent studies that even a low-intensity [20-50% one-repetition maximum (1RM)] resistance exercise can increase muscular size and strength when combined with moderate blood flow restriction (BFR; also known as KAATSU). This type of exercise is performed with restricted venous blood flow and pooling of blood in extremities, thus it may affect the coagulation system. PURPOSE: The purpose of this study was to investigate whether low-intensity resistance exercise with BFR affects the coagulation system. METHODS: Ten healthy young men (aged 22-30 yr) performed 4 sets of leg press exercises with and without BFR (150-160 mmHg) at an intensity of 30% 1RM. In each exercise session, one set with 30 repetitions was followed by 3 sets with 15 repetitions. Blood samples were taken before, and 10 min, 1, 4 and 24 h after the exercise. Prothrombin fragment 1+2 (PTF) and thrombin-antithrombin III complex (TAT) were measured as markers of thrombin generation, whereas D-dimer and fibrin degradation product (FDP) were measured as markers of intravascular clot formation. Changes in plasma volume were calculated from hemoglobin and hematocrit values. The data were analyzed with a two-factor (condition x time) repeated-measures ANOVA. RESULTS: Plasma volume reduction was significantly greater after the exercise with BFR than without (P < 0.05). However, for PTF, TAT, D-dimer and FDP, neither condition x time interactions (PTF, P = 0.28; TAT, P = 0.19; D-dimer, P = 0.76; FDP, P = 0.17) nor main effects for time (PTF, P = 0.84; TAT, P = 0.77; D-dimer, P = 0.09; FDP, P = 0.61) were observed. CONCLUSIONS: These results suggest that low-intensity resistance exercise with blood flow restriction (BFR) does not activate coagulation system and further cause intravascular clot formation in healthy young men.