Optimization of Reproducing the Set Breathing Rhythm During a Cardiorespiratory Synchronism Test

This article analyses optimization guidelines for assessment of human regulatory and adaptive capabilities (RAC) using the cardiorespiratory synchronism (CRS) method. The study participants aged 19 ± 1 were randomized into two groups: main group (n = 30) and reference group (n = 30). In the main group, before conducting the CRS tests, a number of techniques were applied to facilitate reproduction of the set breathing rhythm by the subject: relieving one hand from the ECG electrode by recording a single lead (II or III), which is sufficient to monitor heart rate, for the subjectʼs convenience (with detecting motor asymmetry of the hemispheres); viewing an instructional video showing the algorithm of the upcoming test to the subject; ideomotor training; detecting the latent period of a simple sensorimotor reaction to sound and light stimuli as a preparation for the test. The degree of correspondence between the reproduced and the set breathing rhythms in the main group was 47.0 ± 15.7 % (M ± SD), which is higher than in the reference group. The maximum number of exact respiratory cycles repeated in a row in the first test also demonstrated the advantages of the main group, where this indicator was 10.3 ± 3.4 cycles. The number of respiratory cycles from the beginning of the first test to the exact reproduction of the set rhythm decreased in the main group compared to the reference group by 76.3 %. The correlation analysis revealed no relationship between RAC and the accuracy of breathing rhythm reproduction (correlation coefficient was −0.115 at p = 0.536). Testing duration in the reference group significantly (p < 0.001 according to Mann–Whitney U-test) exceeded that in the main group (by 10.2 min). Thus, the research demonstrated the effectiveness of the proposed techniques for optimizing the CRS test, which can contribute to an even wider spread of this method.