Effects at 24-h modulation of baroreflex sensitivity on blood pressure variability

Blood pressure variability was found to follow a 1/f behaviour. The aim of the authors' study was to verify whether this phenomenon was associated with a concomitant 1/f modulation of the baroreflex sensitivity. In 8 ambulant subjects, systolic blood pressure and pulse interval were continuously monitored for 24 hours and jointly analysed by a sequential procedure to obtain a dynamic estimation of baroreflex sensitivity over day and night. A single spectrum was estimated via FFT from each 24-h sensitivity profile and the presence of the 1/f pattern was evaluated by fitting such a spectrum by a 1/f curve. The authors' results indicate that the baroreflex sensitivity is characterised by marked and systematic short and long-term changes actually following a 1/f behaviour