The Effects of Exercises on the Relationship between Pulse Transit Time and Arterial Blood Pressure

Pulse transit time (PTT) is one of the physiological parameters that can be utilized to estimate arterial blood pressure (BP) non-invasively. However, the effects of successive exercises on the relationship between PTT and BP have not yet been studied systematically. This study examines the variation in PTT and BP on 15 healthy subjects after treadmill exercise. PTT-peak and PTT-foot, which represent the time intervals from the R-wave of electrocardiogram (ECG) to the peak and the foot of photoplethysmographic (PPG) signal, are verified respectively. ECG, PPG signal, systolic blood pressure (SBP) and diastolic blood pressure (DBP) were recorded from each subject. Experiment was divided into pre-exercise, post-exercise1, post-exercise2, and recovery. Treadmill exercise was carried out before post-exercise1 and post-exercise2. It was found that SBP and DBP increased significantly while PTT-foot and PTT-peak decreased significantly immediately after exercises. During the phase of the recovery, increment of PTT-foot and hypotension phenomenon was temporarily observed. Throughout the experiments, PTT-foot and BP were inversely related under the effect of two successive exercises. Therefore, it is possible to estimate BP based on the PTT-approach after successive exercises