Analysis of the diurnal variation of arterial pressure waves

Pulse pressure waves (PPWs) were recorded from the radial artery using photoplethysmography in 7 healthy subjects (6M, 1F, mean age 23 yrs) at rest every 3 hours between 9 am and 6 pm. Analysis of variations of PPWs included sum of square differences between waves, ANOVA and spectral analysis of the components of waves. PPWs recorded at 9am were not significantly different to PPWs recorded at 6 pm, however, PPWs between each other time period were significantly different, with the largest difference occurring between 9 am and 3pm. There was also some variation in the frequency components of the PPWs with an increase in higher frequency components as the day progresses. The finding of this study supports the suggestion within TCM that there are changes in PPW throughout the day.