Voluntary control of breathing does not alter vagal modulation of heart rate

1995 ◽  
Vol 78 (6) ◽  
pp. 2087-2094 ◽  
Author(s):  
A. R. Patwardhan ◽  
J. M. Evans ◽  
E. N. Bruce ◽  
D. L. Eckberg ◽  
C. F. Knapp

Variations in respiratory pattern influence the heart rate spectrum. It has been suggested, hence, that metronomic respiration should be used to correctly assess vagal modulation of heart rate by using spectral analysis. On the other hand, breathing to a metronome has been reported to increase heart rate spectral power in the high- or respiratory frequency region; this finding has led to the suggestion that metronomic respiration enhances vagal tone or alters vagal modulation of heart rate. To investigate whether metronomic breathing complicates the interpretation of heart rate spectra by altering vagal modulation, we recorded the electrocardiogram and respiration from eight volunteers during three breathing trials of 10 min each: 1) spontaneous breathing (mean rate of 14.4 breaths/min); 2) breathing to a metronome at the rate of 15, 18, and 21 breaths/min for 2, 6, and 2 min, respectively; and 3) breathing to a metronome at the rate of 18 breaths/min for 10 min. Data were also collected from eight volunteers who breathed spontaneously for 20 min and breathed metronomically at each subject's mean spontaneous breathing frequency for 20 min. Results from the three 10-min breathing trials showed that heart rate power in the respiratory frequency region was smaller during metronomic breathing than during spontaneous breathing. This decrease could be explained fully by the higher breathing frequencies used during trials 2 and 3 of metronomic breathing. When the subjects breathed metronomically at each subject's mean breathing frequency, the heart rate powers during metronomic breathing were similar to those during spontaneous breathing. Our results suggest that vagal modulation of heart rate is not altered and vagal tone is not enhanced during metronomic breathing.

1994 ◽  
Vol 267 (1) ◽  
pp. H33-H40 ◽  
Author(s):  
J. Hayano ◽  
S. Mukai ◽  
M. Sakakibara ◽  
A. Okada ◽  
K. Takata ◽  
...  

To determine whether paced breathing (PB) and respiratory interval of PB modify the relationship between spectral components of heart rate variability (HRV) and cardiac vagal tone, we studied seven healthy young males under the condition of beta-adrenergic blockade by intravenous propranolol (0.2 mg/kg). Compared with spontaneous breathing, PB at the same respiratory interval as that of individual spontaneous breathing showed no significant effect on the amplitude of the high-frequency (HF) component or the mean R-R interval in either the supine or tilt position, whereas the PB decreased the amplitude of the low-frequency (LF; 0.04–0.15 Hz) component in both positions (P = 0.004 and 0.042, respectively). When the respiratory interval was increased from 3 to 6 s, the HF amplitude showed a progressive increase in both positions (P = 0.001 and 0.035, respectively), while the LF amplitude and mean R-R interval remained unchanged. These results indicate that the effects of PB and respiratory interval on the spectral components of HRV are not mediated by the changes in mean cardiac vagal tone and support the hypothesis that increased respiratory interval amplifies the respiratory-related vagal modulation of heart rate.


1995 ◽  
Vol 79 (3) ◽  
pp. 1048-1054 ◽  
Author(s):  
A. R. Patwardhan ◽  
S. Vallurupalli ◽  
J. M. Evans ◽  
E. N. Bruce ◽  
C. F. Knapp

We investigated the effects of voluntary control of breathing on autonomic function in cardiovascular regulation. Variability in heart rate was compared between 5 min of spontaneous and controlled breathing. During controlled breathing, for 5 min, subjects voluntarily reproduced their own spontaneous breathing pattern (both rate and volume on a breath-by-breath basis). With the use of this experimental design, we could unmask the effects of voluntary override of the spontaneous respiratory pattern generator on autonomic function in cardiovascular regulation without the confounding effects of altered respiratory pattern. Results from 10 subjects showed that during voluntary control of breathing, mean values of heart rate and blood pressure increased, whereas fractal and spectral powers in heart rate in the respiratory frequency region decreased. End-tidal PCO2 was similar during spontaneous and controlled breathing. These results indicate that the act of voluntary control of breathing decreases the influence of the vagal component, which is the principal parasympathetic influence in cardiovascular regulation.


1981 ◽  
Vol 241 (4) ◽  
pp. H620-H629 ◽  
Author(s):  
J. A. Hirsch ◽  
B. Bishop

The relationship of respiratory sinus arrhythmia amplitude (RSA) to tidal volume and breathing frequency was quantified during voluntarily controlled tidal volume and breathing frequency and spontaneous quiet breathing. Seventeen seated subjects breathed via mouthpiece and nose-clip, maintaining constant tidal volumes at each of several breathing frequencies. Inspiratory breath hold was zero frequency. Log RSA was plotted vs. log frequency for each tidal volume. The large stable RSA for frequencies less than 6 cycles/min was called low-frequency intercept (LFI, 20 +/- 5 beats/min). Low-frequency intercept was inversely proportional to a subject's age only to 35 yr. At higher breathing frequencies above a characteristic corner frequency (fC, 7.2 +/- 1.5 cycles/min) RSA decreased with constant slope (roll-off; 21 +/- 3.4 dB/decade). The RSA-volume relationship was linear permitting normalization of RSA-frequency curves for tidal volume to yield one curve. Spontaneous breathing data points fell on this curve. Voluntarily coupling of heart rate to breathing frequency in integer ratios reduced breath-by-breath variability of RSA without changing mean RSA. In conclusion, low-frequency intercept, corner frequency, and roll-off characterize an individual's RSA-frequency relationship during both voluntarily controlled and spontaneous breathing.


2007 ◽  
Vol 135 (3-4) ◽  
pp. 135-142 ◽  
Author(s):  
Danijela Zamaklar-Trifunovic ◽  
Petar Seferovic ◽  
Milan Petrovic ◽  
Mirjana Zivkovic ◽  
Goran Vukomanovic ◽  
...  

Introduction. Autonomic dysfunction is present early in the course of heart failure, and has a direct role on deterioration of cardiac function and prognosis. Heart rate variability (HRV) estimates sympathovagal control of heart frequency. The influence of respiratory pattern on HRV is clinically important. Breathing disorders are common in heart failure and highly affect HRV and autonomic evaluation. It was previously shown that slow and deep breathing increased parasympathetic tone, but effects of this respiratory pattern on HRV were not evaluated. Objective. The aim of the study was to estimate effects of slow and deep breathing (SDB) on HRV in heart failure patients. Method. In 55 patients with heart failure (78% male, mean age 57.18?10.8 yrs, mean EF=34.12?10.01%) and 14 healthy controls (57.1% male, mean age 53.1?8.2 yrs), short term HRV spectral analysis was performed (Cardiovit AT 60, Schiller). VLF, LF, HF and LF/HF were determined during spontaneous and deep and slow breathing at 0.1 Hz (SDB). Results. LF, HF and LF/HF significantly increased during SDB compared with spontaneous breathing both in controls (LF 50.71?61.55 vs. 551.14?698.01 ms2, p<0.001; HF 31.42?29.98 vs.188.78?142.74 ms2, p<0.001 and LF/HF 1.46?0.61 vs. 4.21?3.23, p=0.025) and heart failure patients (LF 27.37?36.04 vs. 94.50?96.13 ms2, p<0.001; HF 12.13?19.75 vs. 41.58?64.02 ms2, p<0.001 and LF/HF 3.77?3.79 vs. 6.38?5.98, p=0.031). Increments of LF and HF induced by SDB were significantly lower in patients than healthy controls. Heart failure patients had lower HRV compared to healthy controls both during spontaneous breathing and SDB. During spontaneous breathing, only HF was significantly lower between healthy controls and patients (p=0.002). During SDB VLF (p=0.022), LF (p<0.001) and HF (p<0.001) were significantly lower in heart failure patients compared to controls. Conclusion. These data suggest that SDB increases HRV both in healthy and heart failure patients; the highest increment is in LF range. Differences in spectral profile of HRV between healthy controls and heart failure patients become more profound during SDB. Controlled respiration during HRV analysis might increase sensitivity and reliability in detection of autonomic dysfunction in heart failure patients. .


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Joseph T. Marmerstein ◽  
Grant A. McCallum ◽  
Dominique M. Durand

AbstractThe vagus nerve is the largest autonomic nerve, innervating nearly every organ in the body. “Vagal tone” is a clinical measure believed to indicate overall levels of vagal activity, but is measured indirectly through the heart rate variability (HRV). Abnormal HRV has been associated with many severe conditions such as diabetes, heart failure, and hypertension. However, vagal tone has never been directly measured, leading to disagreements in its interpretation and influencing the effectiveness of vagal therapies. Using custom carbon nanotube yarn electrodes, we were able to chronically record neural activity from the left cervical vagus in both anesthetized and non-anesthetized rats. Here we show that tonic vagal activity does not correlate with common HRV metrics with or without anesthesia. Although we found that average vagal activity is increased during inspiration compared to expiration, this respiratory-linked signal was not correlated with HRV either. These results represent a clear advance in neural recording technology but also point to the need for a re-interpretation of the link between HRV and “vagal tone”.


Author(s):  
Laura M. J. Fernandez ◽  
Sandro Lecci ◽  
Romain Cardis ◽  
Gil Vantomme ◽  
Elidie Béard ◽  
...  

2017 ◽  
Vol 95 (4) ◽  
pp. 349-355 ◽  
Author(s):  
Luke Anthony Rannelli ◽  
Jennifer M. MacRae ◽  
Michelle C. Mann ◽  
Sharanya Ramesh ◽  
Brenda R. Hemmelgarn ◽  
...  

Diabetes confers greater cardiovascular risk to women than to men. Whether insulin-resistance-mediated risk extends to the healthy population is unknown. Measures of insulin resistance (fasting insulin, homeostatic model assessment, hemoglobin A1c, quantitative insulin sensitivity check index, glucose) were determined in 48 (56% female) healthy subjects. Heart rate variability (HRV) was calculated by spectral power analysis and arterial stiffness was determined using noninvasive applanation tonometry. Both were measured at baseline and in response to angiotensin II infusion. In women, there was a non-statistically significant trend towards increasing insulin resistance being associated with an overall unfavourable HRV response and increased arterial stiffness to the stressor, while men demonstrated the opposite response. Significant differences in the associations between insulin resistance and cardiovascular physiological profile exist between healthy women and men. Further studies investigating the sex differences in the pathophysiology of insulin resistance in cardiovascular disease are warranted.


Author(s):  
Shehan Jayasekera ◽  
Edward Hensel ◽  
Risa Robinson

Background: Natural environment inhalation topography provides useful information for toxicant exposure, risk assessment and cardiopulmonary performance. Commercially available wearable respiratory monitors (WRMs), which are currently used to measure a variety of physiological parameters such as heart rate and breathing frequency, can be leveraged to obtain inhalation topography, yet little work has been done. This paper assesses the feasibility of adapting these WRMs for measuring inhalation topography. Methods: Commercially available WRMs were compiled and assessed for the ability to report chest motion, data analysis software features, ambulatory observation capabilities, participant acceptability, purchasing constraints and affordability. Results: The following WRMs were found: LifeShirt, Equivital EQ02 LifeMonitor, Smartex WWS, Hexoskin Smart Garment, Zephyr BioHarness, Nox T3&A1, BioRadio, SleepSense Inductance Band, and ezRIP & zRIP Durabelt. None of the WRMs satisfied all six assessment criteria in a manner enabling them to be used for inhalation topography without modification and development. Conclusions: The results indicate that there are WRMs with core technologies and characteristics that can be built upon for ambulatory inhalation topography measurement in the NE.


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