A-36 Free Communication/Poster - Vascular Function: MAY 27, 2009 7:30 AM - 12:30 PM ROOM: Hall 4F
"Kaatsu" (ie, blood flow restricted exercise) is a popular exercise modality in Japan and is spreading widely to the rest of the world. The underlying principle of this training is that under the conditions of restricted muscle blood flow, even low-intensity exercise can induce muscle strength and hypertrophy. One concern, however, is that blood flow restriction (BFR) would increase vascular resistance and could induce increase blood pressure as well as myocardial oxygen demand, which may be harmful for those with compromised cardiac function.
PURPOSE: To determine the effects of leg BFR on hemodynamic factors during low intensity aerobic exercise.
METHODS: Eight young (27±4 years) healthy volunteers were studied under parallel conditions on 2 separate days. For each exercise session, the volunteer stood 3 minutes for baseline, followed by five 2 minute walking intervals, with one minute rest between intervals. During the BFR condition, two pneumatic cuffs (inflated to 160mmHg) were placed around the upper thighs. The order of experiments was randomized between the BFR condition and the control (without BFR cuff) condition.
RESULTS: Increases in systolic, mean, and diastolic blood pressure were 2- to 3-fold greater in the BFR session compared with the control session. The elevated blood pressure was associated with higher total peripheral resistance in the BFR session. Cardiac output was similar during both exercise sessions, but stroke volume increased less and heart rate increased more during exercise with the BFR cuffs. As a result, double product, an index of myocardial oxygen demand, was more than 2-fold higher during the BFR condition.
CONCLUSION: Blood flow restriction induces excessive blood pressure responses during low intensity aerobic exercise through increases in total peripheral resistance and cardiac afterload. These results suggest that "Kaatsu" may need to be more cautiously prescribed to those with compromised cardiac conditions.