Master of Science in Education
Wallace, Juliane P
The restriction of muscle blood flow with short term low-intensity exercise has been shown to enhance muscle size and strength. Post exercise hypotension is consistently elicited following 30-60min bouts of moderate intensity (50-60% peak aerobic capacity) exercise. Following an acute bout of exercise, systemic resistance does not completely recover, resulting in post exercise hypotension. Purpose: To determine if exercise with blood flow restriction in healthy individuals is as effective as traditional exercise in eliciting post exercise hypotension. Methods: Ten healthy (age =23±2y; VO2max=38.4±10ml*kg-1*min-1; bodyfat =18±5%) college-aged individuals volunteered to participate in this within subject's design. Participants were randomly assigned to one of two exercise trials: one with blood flow restriction and one without. The normal exercise (NE) trial consisted of level walking at 60% of heart rate max for a total of 60 minutes. Exercise with blood flow restriction (EBR) consisted of level walking at 53.6 m/min (2.0mph) for 20 minutes (two bouts of 10 min). In order to create blood flow restriction, large blood pressure cuffs were placed around the most proximal portion of both legs. Prior to exercise, the pressure in each cuff was set at 100mmHg and increased by 20mmHg while holding for 30s at each pressure and releasing for 10 seconds between increments until the final pressure of 160mmHg was reached. In both exercise trials, heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP) were assessed every 5 minutes. Post exercise HR, SBP, and DBP were assessed every 5 minutes for a total of 60 minutes. Results: SBP was significantly lower post NE at minutes 30(111±4 vs. 115±5 mmHg), 35(109±3 vs. 114±5 mmHg), 40(110±2 vs. 115.4±5 mmHg), and 50(111±4 vs.113±4 mmHg) compared to EBR. DBP was significantly lower in the first 5 minutes post exercise (76±7 vs.83±4 mmHg) in the NE vs. the EBR trial. Post exercise HR was significantly higher in the EBR group at 50 minutes (70 ±10 vs.66±10 bpm). Conclusion: Exercise with blood flow restriction utilizing a lower duration and intensity of exercise does not appear to yield the same post exercise hypotension as traditional moderate intensity exercise.