Acute Effects of Shorter Blood Flow Restriction Cycles on the Microvasculature
Disciplines
Circulatory and Respiratory Physiology
Abstract (300 words maximum)
PURPOSE: To determine whether shorter and more frequent cuff inflations are a preferable alternative to the 5-min blood flow restriction (BFR) protocol, specifically looking at the microvasculature and tissue saturation index (TSI). METHODS: Using a within-subject design, participants completed 4 visits. Visit 1 included familiarization. For visits 2-4, participants had 1 of 3 conditions on the dominant arm while supine: 5-min (BFR5, 5 cycles), 3-min (BFR3, 7 cycles), or 0-min (CON, 7 cycles) of cuff inflation at 80% arterial occlusion pressure (AOP). AOP was measured with an automated device, following an initial 5-min rest with the dominant arm abducted 90 degrees. Heme levels were measured using near-infrared spectroscopy (NIRS) at 1/3 the distance from the lateral epicondyle of the humerus to the styloid process of the radius and adjusted to encompass the wrist flexors. During cuff inflation, the TSI initial slope (S1) and minimum were considered the stimulus. Following deflation, the initial slope (S2) and maximum were considered the microvascular response. For statistical analysis, the 5th cycle was compared across conditions with one-way Bayesian Repeated Measures ANOVAs. Data reported as mean±standard deviation. RESULTS: 10 participants (3 female, 23±3 yr, 78.7±12.2 kg, 171.3±12.5 cm) have completed this study. S1 (BF10=641346.397) was similar between BFR5 (-0.058±0.031) and BFR3 (-0.066±0.017, BF10=0.406). CON (0.001±0.006) was less than BFR5 (BF10=118.281) and BFR3 (BF10=18252.619). S2 (BF10=229.343) was similar between BFR5 (1.088±0.904) and BFR3 (0.810±0.317, BF10=0.479). CON (0.006±0.038) was lower than BFR5 (BF10=12.382) and BFR3 (BF10=997.479). Minimum (BF10=103.155) was lower in BFR5 (48.071±17.174) than BFR3 (52.849±14.810, BF10=2.427) and CON (66.701±5.389, BF10=12.058). CON was higher than BFR3 (BF10=9.897). Maximum (BF10=0.672) was similar across BFR5 (75.940±11.887), BFR3 (74.263±6.393), and CON (69.493±4.681). CONCLUSION: Our preliminary findings suggest that shorter cuff inflations elicit similar changes to microvascular response from a lesser stimulus due to a shorter time under restriction.
Academic department under which the project should be listed
WCHHS - Exercise Science and Sport Management
Primary Investigator (PI) Name
Dr. Daphney Carter
Acute Effects of Shorter Blood Flow Restriction Cycles on the Microvasculature
PURPOSE: To determine whether shorter and more frequent cuff inflations are a preferable alternative to the 5-min blood flow restriction (BFR) protocol, specifically looking at the microvasculature and tissue saturation index (TSI). METHODS: Using a within-subject design, participants completed 4 visits. Visit 1 included familiarization. For visits 2-4, participants had 1 of 3 conditions on the dominant arm while supine: 5-min (BFR5, 5 cycles), 3-min (BFR3, 7 cycles), or 0-min (CON, 7 cycles) of cuff inflation at 80% arterial occlusion pressure (AOP). AOP was measured with an automated device, following an initial 5-min rest with the dominant arm abducted 90 degrees. Heme levels were measured using near-infrared spectroscopy (NIRS) at 1/3 the distance from the lateral epicondyle of the humerus to the styloid process of the radius and adjusted to encompass the wrist flexors. During cuff inflation, the TSI initial slope (S1) and minimum were considered the stimulus. Following deflation, the initial slope (S2) and maximum were considered the microvascular response. For statistical analysis, the 5th cycle was compared across conditions with one-way Bayesian Repeated Measures ANOVAs. Data reported as mean±standard deviation. RESULTS: 10 participants (3 female, 23±3 yr, 78.7±12.2 kg, 171.3±12.5 cm) have completed this study. S1 (BF10=641346.397) was similar between BFR5 (-0.058±0.031) and BFR3 (-0.066±0.017, BF10=0.406). CON (0.001±0.006) was less than BFR5 (BF10=118.281) and BFR3 (BF10=18252.619). S2 (BF10=229.343) was similar between BFR5 (1.088±0.904) and BFR3 (0.810±0.317, BF10=0.479). CON (0.006±0.038) was lower than BFR5 (BF10=12.382) and BFR3 (BF10=997.479). Minimum (BF10=103.155) was lower in BFR5 (48.071±17.174) than BFR3 (52.849±14.810, BF10=2.427) and CON (66.701±5.389, BF10=12.058). CON was higher than BFR3 (BF10=9.897). Maximum (BF10=0.672) was similar across BFR5 (75.940±11.887), BFR3 (74.263±6.393), and CON (69.493±4.681). CONCLUSION: Our preliminary findings suggest that shorter cuff inflations elicit similar changes to microvascular response from a lesser stimulus due to a shorter time under restriction.