Time–frequency analysis of variabilities of heart rate, systolic blood pressure and pulse transit time before and after exercise using the recursive autoregressive model

摘要: Abstract Time–frequency (T–F) analysis is often used to study the non-stationary cardiovascular oscillations such as heart rate and blood pressure variabilities in dynamic situations. This intends use T–F recursive autoregressive technique investigate variability pulse transit time (PTT), which a parameter of emerging interest due its potential estimate non-invasively, continuously without cuff. Recent studies suggest that PTT not only related systolic (SBP) but also rate. Therefore, this study, analyzed together with R–R interval (RRI) from electrocardiogram beat-to-beat SBP on 9 normotensive subjects before shortly after three successive bouts treadmill exercise. The results showed both low frequency (LF) high (HF) components were found spectra RRI, 5-min recordings collected Compared baseline, decrease power HF component RRI followed by an increase LF indicated firstly vagal withdrawal then sympathetic activity enhancement On other hand, although changes more similar those than LF/HF ratio was almost 4 times higher PTT. Based results, it therefore suggested relationship between frequency-dependent.