Influence of age on linear and nonlinear measures of autonomic cardiovascular modulation.
BACKGROUND
Age has been identified as an independent risk factor for cardiovascular diseases. In addition, autonomic imbalance toward sympathetic preponderance has been shown to facilitate the occurrence of heart disease. Here, we aimed to assess autonomic modulation of cardiovascular parameters during normal ageing applying well-established linear and novel nonlinear parameters.


METHODS
Linear and nonlinear measures of heart rate variability and complexity as well as measures of QT interval variability and baroreflex sensitivity were obtained from a total of 131 healthy, medication-free participants from a continuous age range between 20 and 90 years, who were allocated to three different age groups.


RESULTS
Heart rate variability and complexity significantly decreased with age, while regularity of heart rate time series increased. In addition, QT interval variability linearly increased with age, while baroreflex sensitivity showed a pronounced decrease. Overall, concerning effects of ageing, linear and nonlinear parameters showed equal differentiation between groups.


CONCLUSIONS
These data indicate a shift of autonomic balance toward sympathetic predominance in higher age groups, limiting the reactiveness of the cardiovascular system to adjust to different demands and increasing the risk for developing tachyarrhythmias.
Department of Psychiatry and Psychotherapy, University Hospital, Jena, Germany.
Michael K
MK
Boettger
Steffen
S
Schulz
Sandy
S
Berger
Manuel
M
Tancer
Vikram K
VK
Yeragani
Andreas
A
Voss
Karl-Jürgen
KJ
Bär
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000428:Alcohol Drinking; D000704:Analysis of Variance; D017704:Baroreflex; D001794:Blood Pressure; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006339:Heart Rate; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D012737:Sex Factors; D012907:Smoking; D055815:Young Adult