Orthostatic response of cephalic blood flow using a mini laser Doppler blood flowmeter and hemodynamics of a new active standing test

Purpose Cephalic hemodynamic assessment is important in initial orthostatic hypotension. We sought to investigate cephalic blood flow (CBF) in the earlobe using a mini laser Doppler flowmeter (LDF) during orthostatic challenge. In addition, we clarified hemodynamic differences during a new active standing protocol using a footstool standing test (FST) with bending of the legs on the footstool in the sitting position to reduce the load of the squatting posture in the conventional squat standing test (SST). Methods Ten healthy men (21 ± 0.5 years) performed the SST after a 1 min squat and the FST after a 1 min load consisting of bending the legs on a footstool in the sitting position. Earlobe CBF, beat-to-beat arterial blood pressure (ABP), mean arterial blood pressure (MAP), and heart rate (HR) were recorded during each test. Results Earlobe CBF showed a transient fall synchronized with the ABP during each test. No significant differences in the recovery times (RTs) of CBF and MAP were observed during the SST (CBF 12.9 ± 0.6 s vs. MAP 12.1 ± 0.5 s, P = 0.313) and FST (CBF 10.6 ± 0.4 s vs. MAP 10.1 ± 0.8 s, P = 0.552). Although the CBF and ABP decreases were not different in each test, the HR increase was significantly lower with the FST (24 ± 2 bpm) than with the SST (31 ± 3 bpm, P