This study discriminates the microcirculatory responses to the application of pressure stimulation (PS) using approximate entropy (ApEn) analysis to characterize the temporal fluctuations within beat-to-beat laser Doppler signals. Experiments were performed with a control group in which PSs were not applied and with five groups in which PSs of 20, 60, 100, and 160 mmHg were applied, respectively. Each experiment involved making a 20-minute baseline recording and then recording effect data 0-20 minutes (M1) and 50-70 minutes (M2) after stopping skin-surface PS. ApEn and wavelet analyses were performed on the assessed laser Doppler signals. At the pressed site, a significant microcirculatory blood flow (MBF) increase was observed that persisted to M2 only in the 60-mmHg PS group (PS60). The only significant increase in ApEn also occurred in PS60, and the only significant decrease in ApEn occurred in the 100-mmHg PS group. Changes in ApEn can help the identification of the range of PSs that can induce longer-persisting improvements in the MBF. These changes in MBF parameters and ApEn can be attributed to different levels of the pressure-induced vasodilation response. The p