Impact of chronic intermittent forearm compressions on blood flow capacity in humans

Exercise training is known to enhance muscle blood flow capacity (BFC), but the mechanisms that mediate this adaptation are poorly understood. We tested the hypothesis that long‐term application of intermittent pneumatic compressions (IPC) in the forearm increases BFC. Twelve healthy subjects were randomly assigned to three compression groups: 50, 100, and 150mmHg and underwent a program of IPC in the non‐dominant forearm (1h/day, 5d/week) for 4 weeks. IPC were achieved by cyclically inflating/deflating (2s on/3s off) two cuffs wrapped around the forearm using a cuff inflator unit. Peak forearm blood flow (PFBF, ml(100ml) −1 min −1 ) and peak forearm vascular conductance (PFVC, ml.min −1 mmHg −1 ) were measured with Doppler ultrasound following 10 min of forearm ischemia pre, mid and post IPC intervention. In the 150mmHg group, PFBF in the non‐dominant forearm increased from 21±1 at pre‐intervention to 27±1 and 30±2 (p<0.05) at mid and post intervention, respectively, while no changes were observed in the control forearm. Likewise, PFVC showed a trend for increase following IPC (p=0.1) only in the experimental forearm (0.28±0.02, 0.32±0.01, 0.35±0.02 at pre, mid and post intervention, respectively). No significant changes were detected in the 50 and 100mmHg groups. In conclusion, this study demonstrates that daily IPC of 150 mmHg independently enhances forearm BFC in humans. (NIH HL‐36088 and ACSM Foundation).