Effects Of Cool-down Methods Subsequent To Blood Flow Restriction Walking On Microvascular Responsiveness

Performing low-intensity aerobic exercise with blood flow restriction (BFR) has been shown to elicit positive improvements after training, such as increased maximal oxygen uptake. However, lower macrovascular vasodilatory responsiveness has been reported following BFR walking. PURPOSE: The primary aim was to investigate the potential effect that exercise (control (CON), BFR) and cool-down (supine, rolling massage (RM), walk) methods have on microvascular responsiveness. METHODS: 15 healthy, trained participants (8 Female, 6 Male, age 22 ± 1 years, height 1.70 ± 0.07 meters, weight 66.0 ± 9.6 kilograms) completed four 15-minute walking sessions. During session 1, participants walked at a 3/10 rating of perceived exertion (RPE) with no BFR and then rested supine. During sessions 2-4, participants walked at the same session 1 speed with BFR applied bilaterally to the proximal thighs at 60% limb occlusion pressure. Following sessions 2-4, participants either rested supine, had RM performed on the thigh for two minutes and then rested supine, or actively walked without BFR for two minutes and then rested supine. Microvascular responsiveness was measured before and 20 minutes after each walking session using the vascular occlusion test (VOT; 2-minute baseline, 5-minute arterial occlusion, 8-minute recovery) in the quadriceps and calf muscles. The reperfusion slope of tissue oxygen saturation was measured via near-infrared spectroscopy during the 8-minute VOT recovery and used as an index of microvascular responsiveness. Two-way repeated measures analysis of variance was performed to assess if condition (CON, BFR + Supine, BFR + RM, BFR + Walk) and/or test (pre-exercise, post-exercise) affected the reperfusion slope. Statistical significance was set at p < 0.05. RESULTS: The reperfusion slope increased in the quadriceps (0.88 ± 0.74 %/s vs 1.07 ± 0.70 %/s) and calf (0.56 ± 0.57 %/s vs 0.75 ± 0.70 %/s) muscles after exercise. No significant differences in reperfusion slope were observed between conditions. CONCLUSION: Small positive changes in microvascular responsiveness occurred following 15-minute walking bouts in the quadriceps (ES = 0.26) and calf (ES = 0.30) despite exercise condition or cool-down method.