Cold face immersion decreased the fractal scaling index alpha1 from 0.85 to 0.67 (P<0.0001), whereas cold hand immersion increased it from 0.77 to 0.97 (P<0.01).
How do cold face and cold hand immersion affect the fractal organization of human heart rate dynamics in healthy subjects?
The fractal organization of human heart rate dynamics is determined by the interplay between sympathetic and vagal outflow, with breakdown toward random dynamics occurring during coactivation.
Absolute Event Rate: 0.67% vs 0.85%
p-value: p=<0.0001
BACKGROUND: Altered fractal heart rate (HR) dynamics occur during various disease states, but the physiological background of abnormal fractal HR behavior is not well known. We tested the hypothesis that the fractal organization of human HR dynamics is determined by the balance between sympathetic and vagal outflow. METHODS AND RESULTS: A short-term fractal scaling exponent (alpha1) of HR dynamics, analyzed by the detrended fluctuation analysis (DFA) method, and the high-frequency (HF) and low-frequency (LF) spectral components of R-R intervals (0.15 to 0.4 Hz; n=13), along with muscle sympathetic nervous activity (MSNA) from the peroneus nerve (n=11), were assessed at rest and during cold face and cold hand immersion in healthy subjects. During cold face immersion, HF power increased (from 6.9+/-1.3 to 7.6+/-1.2 ln ms2, P<0.01), as did MSNA (from 32+/-17 to 44+/-14 bursts/100 heartbeats, P<0.001), and LF/HF ratio decreased (P<0.01). Cold hand immersion resulted in a similar increase in MSNA (from 34+/-17 to 52+/-19 bursts/100 heartbeats, P<0.001) but a decrease in HF spectral power (from 7.0+/-1.3 to 6.5+/-1.1 ln ms2, P<0.05) and an increase in the LF/HF ratio (P<0.05). The fractal scaling index alpha1 decreased in all subjects (from 0.85+/-0.27 to 0.67+/-0.30, P<0.0001) during cold face immersion but increased during cold hand immersion (from 0.77+/-0.22 to 0.97+/-0.20, P<0.01). CONCLUSIONS: The fractal organization of human HR dynamics is determined by a delicate interplay between sympathetic and vagal outflow, with the breakdown of fractal HR behavior toward more random dynamics occurring during coactivation of sympathetic and vagal outflow.
Tulppo et al. (Tue,) conducted a other in Healthy subjects (n=13). Cold face and cold hand immersion vs. Rest was evaluated on Fractal scaling index alpha1 during cold face immersion (p=<0.0001). Cold face immersion decreased the fractal scaling index alpha1 from 0.85 to 0.67 (P<0.0001), whereas cold hand immersion increased it from 0.77 to 0.97 (P<0.01).
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: