Respiratory-Vagal Modulatory Effects of Cold Face Test on the High Frequency Components of Systolic and Diastolic Blood Pressure Variability

Alejandra Guillén-Mandujano1, Salvador Carrasco-Sosa1, Aldo Mejía-Rodríguez2
1Universidad Autónoma Metropolitana-I, 2Universidad Autónoma de San Luis Potosí, SLP


To provide insight into the generating mechanism of the high-frequency components (HF) of diastolic (DBP) and systolic (SBP) blood pressure variability (BPV), which has not been sufficiently clarified by the few reported studies addressing it, we assessed and compared, in 23 healthy volunteers, the respiratory and vagal effects evoked by the cold face test (CFT) on the instantaneous 120-s time-courses of HF powers (PHF) and central frequencies (CFHF) of RR intervals (PHFRR, CFHFRR), respiration (PHFRES, CFHFRES), SBP (PHFSBP, CFHFSBP) and DBP (PHFDBP, CFHFDBP), estimated by a time-frequency distribution, their gains (GHF) in relation to PHFRES (GHFRR, GHFSBP, GHFDBP), computed by alpha index, and their respective coherences (COHFRR, COHFSBP, COHFDBP). Ensemble averages of PHF and GHF dynamics (similar to each other) presented two distinctive response patterns: one of large and progressive increase that reaches a plateau, shown by PHFRR and PHFDBP, and the other of small, sustained increment, depicted by PHFSBP and PHFRES. PHFDBP and GHFDBP means were greater (p<0.04) than PHFSBP and GHFSBP means. Mean correlation of PHFRR with PHFDBP was greater than with PHFSBP (Table). Correlation of PHFRES with PHFSBP was greater than with PHFDBP (Table). Correlations between GHF measures behaved similarly to PHF (Table). Response patterns and mean values of CFHFRR, CFHFDBP and CFHFSBP were similar to those of CFHFRES: relative to control, all decreased (p<0.02). Mean COHFSBP was greater than (p<0.02) mean COHFDBP. CFT provokes large increment of vagal activity and slight respiratory changes, increase of PHFRES and reduction of CFHFRES, with distinctive effects on HF of BPV: on PHFDBP, a large modulatory effect, better correlated with PHFRR, possibly mediated by this measure of vagal activity, and on PHFSBP, a small modulatory increment, with better correlation and coherence with PHFRES, most likely associated to the mechanical respiratory influence. Moreover, CFHFRES drives CFHFSBP, CFHFRR, and CFHFDBP changes.