The influence of expiration and inspiration duration on respiratory heart arrhythmia

Abstract

Objective. To study the effect of the duration of inhalation and exhalation, and their relation to the respiratory heart arrhythmia (RHA) and observe changes in vagal tone during the test.

Methods. 13 non-smoking subjects were selected (4 of them men) with an average age of 20 + \ - 2 years, they were all healthy, don’t suffer of cardiac arrhythmia, not obese and don’t take drugs, also don’t drink caffeine-containing products for 4 hours before the experiment.

Procedure. The subjects were instructed at first to breathe as usual, then quickly inhale (3 seconds) and slow exhale (7 seconds) and vice versa. Breathing and heart rate were recorded using biopac. Also subjects underwent tests about their anxiety and the state of the autonomic nervous system by Spielberger, by Moldovanu.

Results. According to the results of tests were increased values for the state of nervous, cardiovascular and digestive systems, shortness of breath, tremor and tetany. 5 subjects overestimated all indicators. The breathing rate was 6\min. During the test with a short inspiration after a long expiration (P = 0.00214), RHA was higher than vice versa (P = 0.000775). The heart frequency in both experiments was 89 b\m. The correlation hf\lf bands in 3\7 experiment was 0,09 and in 7\3 experiment 0,083.

Conclusions. RHA amplitude is influenced by the respiration rate and the amount of air exchanged per breath. Reducing the frequency of breathing increases RHA. Inspire blocks vagal cardiac regulation. During the test with a short inspiration after a long expiration vagal tone and RHA, was higher than in a long inspiration after a short expiration. The experiment also showed that the correlation of hf\lf bands has no effect on heart rate variability.