MULTISCALE ENTROPY AND MULTISCALE TIME IRREVERSIBILITY ANALYSIS OF RR TIME SERIES DEPENDING ON AMBIENT TEMPERATURE

摘要

Purpose: The main aim of this paper is to study the influence of temperature on multiscale entropy (MSE) and multiscale time irreversibility (MTI) through the use of short-term measurements. Methods: A total of 12 physically active, healthy, and nonsmoker individuals (25.6 +/- 3.9 years old; 174.2 +/- 7.5 cm of height; and 68.6 +/- 11.1 kg of body mass) voluntarily participated in this study. Two beat-to-beat recordings of 15 min length were performed on every participant, one under hot conditions (35 degrees C) and the other assessment under cool conditions (19 degrees C). The order of these two assessments was randomly assigned. Multiscale sample entropy and MTI were assessed in every measurement through 10 scales. Results: Entropy was significantly higher under hot conditions (p < 0.05) from the fifth scale compared to cool conditions. On the contrary, MTI values were significantly lower under hotter conditions (p < 0.05). Conclusions: The study of MSE and time irreversibility of short RR measurements presents consistent and reliable data. Moreover, exposures to hot conditions provoke an increment of interbeat complexity throughout larger scales and a decrease in the MTI in a healthy population.