Spectral Analysis of Korotkoff Sounds

Korotkoff sounds were recorded and spectrally analyzed for five adult males at rest, during exercise, and immediately after exercise. The spectrum representing the average over the five subjects was calculated for each of the four Korotkoff sound phases under each condition. The average spectra thus obtained are presented so as to provide a comparison between the different phases and exercise conditions. The results provide a quantitative picture of the criteria by which the various phases and endpoints are distinguished. They should be useful in the design of filters for indirect blood pressure monitoring equipment.