ABSTRACT
The cardiorespiratory plasticity in healthy children 9-10 years old (n = 72) was studied during the procedure of paced breathing. The observations of a child after an informed consent taken from him, his parents and teachers were carried out by a psychologist, a physiologist and a doctor after the lessons. In a preliminary series 1 minute trials of pace breathing with various frequencies (22-5.5 times/minute) were used which showed a good endurance of slow breathing. Inthemain series a 3 minute baseline recording and 4-5 periods of 1.5 minute duration with a stepwise reduction of breathing rate of 12, 8, 7, 6 times/minute and in 10 children - 5.5 times/minute were registered. Computer-aided pacer set the durations of inspiration, expiration, pause. The main parameters of heart-rate variability (HRV) and corresponding FFT spectra were analyzed by ANOVA. In children a high cardiorespiratory plasticity of heart rhythm according to frequency of pace breathing is observed. During the stepwise reduction of breathing rate a quasilinear growth of HRV and peak power of FFT spectra of RR-intervals are registered, reaching the maximum level in a HF-band at 12 breaths/min and in LF-band at frequencies of 6-5.5 that are critical to the sustained volitional control of cardiorespiratory processing in children. At 6-5.5 breaths/min a growth of HF-band power of heart rhythm modulation is also registered.
Subject(s)
Heart Function Tests/standards , Heart Rate , Respiration , Respiratory Function Tests/standards , Attention , Biological Variation, Individual , Child , Female , Heart Function Tests/methods , Humans , Male , Respiratory Function Tests/methodsABSTRACT
The aims of the work were the study of cardiorespiratory coupling by method of paced breathing and the analysis of heart rate variability in men. Heart rhythm of 14 athletes and 12 non-athletes, 21 ± 1.4 years old, was registered in 3 minute sessions during spontaneous and paced breathing 14, 10, 9, 8, 7, 6, 5, 4 times/minute. The subjects were following breathing rate from a display. Initial heart rate being more slow in athletes (p < 0.05) was retained during episodes of controlled breathing. The power of FFT spectra peaks of RR-intervals was growing quasilinearly during reduction of breathing rate, reaching its peak value at 5-4 breaths/minute in athletes. More pronounced modulations of RR intervals were observed in HF spectral band (p < 0.05) of athletes breathing 14-10 times/minute compared to non-athletes. The power of LF band of the spectrum in athletes breathing 8-4 times/minute was 2 times higher: variability of RR-intervals "shrinked" accordingly to paced breathing rate. The dominant role in slow oscillations of heart rate manifested by paced respirations with involvement of vagus baroreflex afferentations of lungs and chest is hypothesized to be the consequence of breathing under attentional control.
Subject(s)
Athletic Performance/physiology , Basketball/physiology , Heart Rate/physiology , Respiratory Rate/physiology , Volleyball/physiology , Adaptation, Physiological , Adult , Breathing Exercises , Fourier Analysis , Humans , Male , Monitoring, Physiologic , Young AdultABSTRACT
The effect of paced breathing 10, 9, 8, 7, 6, 5, 4 times per minute with 160 and 90 s duration on the plasticity of slow modulations of heart rate was studied on 29 participants aged 21, both men and women. It was shown that the power spectrum of RR-intervals have dominant harmonics both in high- and low-frequency domains, peaking at 0.08-0.06 Hz for 160 s segments. Low-frequency peaks of the spectrum were growing in power linearly as a result of the graded slowing down of breathing rate. Frequency-dependent modulations of RR-intervals for a wide range of breathing frequencies confirm a substantial cardio-respiratory plasticity underlying cognitive and somatic processing.
