Time-frequency representation of cardiovascular signals during handgrip exercise

Altering cardiovascular oscillation is present during various interventions, e.g. in autonomic tests. Traditional spectral analysis suffers from nonstationary data and poor time resolution when studying the dynamics and frequency of cardiovascular signals. Smoothed pseudo Wigner-Ville representation method was applied when analyzing handgrip (HG) data of healthy men (n = 3D11). Prevalent low frequency (PLF) and LF/HF powers were estimated from the time-frequency representation (TFR). According to the experimental results, PLF increases during HG with both heart rate interval (RRi) and systolic blood pressure (SBP) data. In addition, TFR revealed the increasing LF power during the HG with both RRi and SBP, while HF power increases with SBP and decreases with RRi. This is interpreted as an altered sympatho-vagal balance during the hand grip protocol.