[The dependence of the heart rhythm on anxiousness as a stable individual characteristic]

In 90 subjects (25 males and 65 females) aged 17-19 heart and respiration rates were telemetrically recorded with a "Sport" polygraph under conditions of rest and arithmetical load (periods of 3 min each). Spectral analysis of heart rate and respiration and statistical processing was performed off-line by an IBM PC XT with the software package PFE2. Anxiety was tested according to Spielberger State-Trait-Anxiety Inventory with Hanin modification and strength of excitation and inhibition according to Strelau Temperament Inventory. It was shown that the group characterized by the high trait-anxiety had significantly higher resting heart rate and Baevskiĭ index of strain than the group with low trait-anxiety. The groups differed also in R-R interval variability (standard deviation) under arithmetic load. In the group with high trait-anxiety R-R interval variability was lower than in the other group mainly in two frequency bands of R-R power spectrum, i. e., those of respiratory arrhythmia (RA) and Traube-Hering-Mayer waves (THM). Mental load evoked an increase in the heart rate and Baevskiĭ index and decrease in the power of RA and THM frequency bands. Such peculiarities of the heart rate in both groups during the periods of rest and informational load can be explained in the framework of reciprocal relationship between orienting (lower trait-anxiety, lower heart rate, higher R-R interval variability mainly in RA and THM bands of R-R power spectrum) and defensive reflexes (higher trait-anxiety, higher heart rate, lower R-R interval variability, in particular in RA and THM bands of R-R power spectrum.