Leg blood flow and cardiac output are cyclically reduced during low‐intensity exercise with intermittent KAATSU cuff inflation in young adults

Figures

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  FIGURE 1. All exercise was performed on a two‐legged knee flexion/extension ergometer.

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  FIGURE 2. Schematic representation for (a) experimental visit test protocol, (b) timepoints within a single KAATSU Cycle, and (c) cuff pressure throughout the KAATSU Cycle protocol. For KAATSU Cycle, the time from the start of inflation to the desired pressure varied between participants. CTL, control; EX, exercise; SKU, standard KAATSU units.

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  FIGURE 3. Schematic of leg blood flow, arterial blood pressure, and leg vascular conductance measurements. Doppler and echo ultrasound was used to measure common femoral artery (CFA) blood flow proximal to the KAATSU cuff, which reflects total perfusion through the exercising legs. Systemic arterial blood pressure—the driving pressure for leg blood flow—was measured via photoplethysmography. “Virtual” leg vascular conductance was calculated as leg blood flow/arterial blood pressure. Virtual vascular conductance encompasses (1) cuff compression force on microvasculature beneath the cuff, (2) venous congestion distal to cuff, (3) effect of muscle contractions on resistance vessel and venous compression, and (4) the vasodilation of resistance vessels beneath and distal to the cuff.

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  FIGURE 4. Consolidated Standards of Reporting Trials (CONSORT) participant flowchart. CFA, common femoral artery.

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  FIGURE 5. The effect of the first two KAATSU cycles (150–160 mmHg) on (a) two‐leg blood flow (2LBF), (b) virtual two‐leg vascular conductance (2LVCVIRT), and (c) mean arterial pressure (MAP). Individual participant data are presented as the thin horizontal/angled gray lines, with male participants represented by dashed lines, and females represented by solid lines. Significance indicated by p < 0.05.

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  FIGURE 6. The effect of KAATSU Cycles 3–8 (170–220 mmHg) on (a) two‐legged blood flow (2LBF), (b) virtual two‐leg vascular conductance (2LVCVIRT), and (c) mean arterial pressure (MAP). *Significant difference from CTL (p < 0.05).

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  FIGURE 7. The effect of the first two KAATSU cycles (150–160 mmHg) on (a) cardiac output (CO), (b) heart rate (HR), and (c) stroke volume (SV). Individual participant data are presented as the thin horizontal/angled gray lines, with male participants represented by dashed lines, and females represented by solid lines. Significance indicated by p < 0.05.

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  FIGURE 8. The effect of KAATSU Cycles 3–8 (170–220 mmHg) on (a) cardiac output (CO), (b) heart rate (HR), and (c) stroke volume (SV). *Significant difference from CTL (p < 0.05).