Power spectra of interbeat intervals (IBI) and systolic blood pressure (SBP) were calculated (beat-to-beat blood pressure recordings, Finapres), baroreflex sensitivity (BRS) was determined by four continuous techniques at rest and during exercise in 38 subjects. The product of the amplitude of 0.1 Hz component in IBI a SBP was BRS independent at rest, but it positively correlated with BRS during exercise, similarly as the variability of IBI.