A SYSTEM FOR NONINVASIVELY MEASURING BLOOD-PRESSURE ON A TREADMILL

Measurement of signal to artifact ratio yielded optimal frequencies fo r a Korotkoff-based automatic system for measuring blood pressure on a treadmill. Maximal Korotkoff sounds occurred just above the crease of the elbow over the brachial artery. Output of a piezoelectric microph one and charge amplifier was measured during treadmill exercise for fr equency bands from 8 to 57 Hz. An automatic system filtered output fro m 40 to 45 Hz, rectified it, then compared it to a threshold that had fixed and exponentially decaying components. For five subjects, the sy stem decisions of systolic and diastolic pressures compared well with those of two observers using stethoscopes. The system shows promise fo r improved measurements of blood pressure during treadmill exercise.