Time Courses of Central Frequencies of Low Frequency Components of Systolic and Diastolic Pressures and RR Intervals Variabilities in Response to Incremental Isometric Exercise

• Published in: Computing in cardiology pp. Page 1 - Page 4
• Main Authors: Guillen-Mandujano, Alejandra, Carrasco-Sosa, Salvador
• Format: Conference Proceeding
• Language: English
• Published: Creative Commons 01.09.2019
• Subjects: Correlation; Force; Frequency estimation; Heart rate variability; Legged locomotion; Resonant frequency; Time-frequency analysis
• ISSN: 2325-887X
• DOI: 10.22489/CinC.2019.010

To test the sympathetic activity estimating capability of central frequencies of low frequency ( CF LF) components of systolic pressure ( CF LF SP ), diastolic pressure ( CF LF DP ) and R-R intervals ( CF LF RR ), in 31 healthy subjects performing continuously increasing legs muscle force until fatigue, we assessed: the instantaneous time courses of CF LF SP , CF LF DP , CF LF RR , their respective low frequency powers ( P LF), estimated by a time-frequency distribution, CF LF- P LF correlations and the comparisons between CF LF. Based on the threshold effect they showed, the time courses of all measures were divided into before (BTP) and after (ATP) threshold periods. Time courses of CF LF SP , CF LF DP and CF LF RR showed: 1. similar patterned responses of gradual increment in BTP, abrupt decrease in ATP and fast increment in the initial recovery period (IRP), inverse to the pattern presented by PLF dynamics; 2. 20-s epoch means (EM) differences (p<0.04) between them in control and BTP according to the inequality CF LF RR > CF LF SP > CF LF DP , that disappeared in ATP and IRP. CF LF- P LF correlations (p<0.01) of the three variables were negative and greater (p<0.01) in ATP than BTP and IRP. Our findings support that CF LF can be used as sympathetic activity measures with some specificity: CF LF RR for the cardiac sympathetic outflow and CF LF DP for the vasomotor one.