TY - JOUR
T1 - Normalized entropy applied to the analysis of interindividual and gender-related differences in the cardiovascular effects of stress
AU - Anishchenko, T.
AU - Igosheva, N.
AU - Yakusheva, T.
AU - Glushkovskaya-Semyachkina, O.
AU - Khokhlova, O.
N1 - Funding Information:
Acknowledgements The research described in this publication was made possible in part by Award No. REC-006 from the US Civilian Research Development Foundation for Former Soviet Union Republics (CRDF) and a grant from the Royal Society of London. N. Igosheva expresses appreciation to INTAS for their support, grant (YSF 99-40-49). The authors wish to thank Prof. Yu.
PY - 2001
Y1 - 2001
N2 - Nonlinear dynamic methods are considered to be a potential tool for studying the complex behavior of the cardiovascular system. In the present study, interindividual and gender-related differences in cardiovascular (CV) responses to various stress stimuli were studied using conventional CV variables such as heart rate (HR) and blood pressure (BP), as well as a recently introduced criterion of system complexity, normalized entropy (E/H, where E is entropy and H is system energy). A group of healthy students (n=270) of both genders (17-20 years of age) were subjected to noise exposure, mental arithmetic, arithmetic against noise and examination stress. Results showed that CV reactivity depended upon the kind of stress imposed and the gender of the subject. HR and BP stress-induced responses did not differ between men and women. However, men had higher absolute BP levels at baseline and during exposure to stressors. Stress-induced pressor responses lasted longer in men than in women. Changes in the complexity degree of CV signals, as assessed by E/H, were more pronounced and prolonged than those of HR and BP. Unlike the latter, E/H changed significantly in all stress situations for each subject tested and could be divided into two types of stress-induced response. These results allow one to conclude that E/H can better quantitate individual differences in CV stress reactivity in comparison with HR and BP. These findings suggest that stress-induced changes in CV functioning are more varied than can be revealed by applying conventional CV measures.
AB - Nonlinear dynamic methods are considered to be a potential tool for studying the complex behavior of the cardiovascular system. In the present study, interindividual and gender-related differences in cardiovascular (CV) responses to various stress stimuli were studied using conventional CV variables such as heart rate (HR) and blood pressure (BP), as well as a recently introduced criterion of system complexity, normalized entropy (E/H, where E is entropy and H is system energy). A group of healthy students (n=270) of both genders (17-20 years of age) were subjected to noise exposure, mental arithmetic, arithmetic against noise and examination stress. Results showed that CV reactivity depended upon the kind of stress imposed and the gender of the subject. HR and BP stress-induced responses did not differ between men and women. However, men had higher absolute BP levels at baseline and during exposure to stressors. Stress-induced pressor responses lasted longer in men than in women. Changes in the complexity degree of CV signals, as assessed by E/H, were more pronounced and prolonged than those of HR and BP. Unlike the latter, E/H changed significantly in all stress situations for each subject tested and could be divided into two types of stress-induced response. These results allow one to conclude that E/H can better quantitate individual differences in CV stress reactivity in comparison with HR and BP. These findings suggest that stress-induced changes in CV functioning are more varied than can be revealed by applying conventional CV measures.
KW - Blood pressure
KW - Electrocardiography
KW - Gender characteristics
KW - Nonlinear dynamics
KW - Stress
UR - http://www.scopus.com/inward/record.url?scp=0034890966&partnerID=8YFLogxK
U2 - 10.1007/s004210100470
DO - 10.1007/s004210100470
M3 - Article
C2 - 11560083
AN - SCOPUS:0034890966
VL - 85
SP - 287
EP - 298
JO - European Journal of Applied Physiology
JF - European Journal of Applied Physiology
SN - 1439-6319
IS - 3-4
ER -