Exhaled Methane is Associated with a Lower Heart Rate

Background: In humans, methane (CH4) is exclusively produced by the intestinal microbiota and has been implicated in several conditions including cardiovascular disease. After microbial production of CH4 in the gut, it steadily crosses into the systemic circulation and reaches the lungs where it can be detected in the exhaled breath, as a surrogate measure for intestinal CH4 production. Recent reports have shown an association between CH4 and vagal dysfunction as well as the inhibition of CH4 activity on ileal contractions with atropine, suggesting its action on the parasympathetic nervous system. Given these findings we hypothesized that CH4 may be affecting resting heart rate based on the potential effect of CH4 on the vagus nerve. Objectives: Given its possible role in the parasympathetic nervous system, we aimed to study the relationship between breath CH4 and resting heart rate (HR) in humans. Additionally, we performed a longitudinal study analyzing the change in HR and its association to breath CH4 over time. Methods: First, we reviewed 1,126 subjects and compared HR in subjects with detectable and undetectable breath CH4. Second, we performed a post-hoc analysis of a randomized control trial to compare the change in HR for those who had an increase in breath CH4 vs those that had a decrease in breath CH4 over 14 weeks. Lastly, we assessed whether a larger decrease in CH4 is associated with a larger increase in HR over time. Results: In the retrospective cohort, subjects with detectable CH4 had a lower HR compared to those with undetectable CH4 (73.0±0.83 vs 76.0±0.44 beats/min; p=0.01). In the post-hoc analysis, a decrease in CH4 over time was associated with an increase in heart rate (median ∆ = 6.5 ± 8.32 beats/min, p=0.0006). Lastly, we demonstrated a biological gradient whereby a larger drop in CH4 is associated with a greater increase in heart rate (R= -0.31, p=0.03). Conclusion: Our findings suggest a potential role for the microbiome (and specifically CH4 from methanogens) to regulate heart rate. Considering these findings, mechanistic studies are warranted to further investigate this potential novel microbiome-neurocardiac axis.

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RNAseq shows an all-pervasive day-night rhythm in the transcriptome of the pacemaker of the heart

Scientific Reports ◽

10.1038/s41598-021-82202-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Yanwen Wang ◽

Cali Anderson ◽

Halina Dobrzynski ◽

George Hart ◽

Alicia D’Souza ◽

...

Keyword(s):

Heart Rate ◽

Nervous System ◽

Circadian Clock ◽

Sick Sinus Syndrome ◽

Sinus Node ◽

Signalling Pathways ◽

Resting Heart Rate ◽

Ion Channel Regulation ◽

Channel Regulation ◽

Physiological Systems

AbstractPhysiological systems vary in a day-night manner anticipating increased demand at a particular time. Heart is no exception. Cardiac output is primarily determined by heart rate and unsurprisingly this varies in a day-night manner and is higher during the day in the human (anticipating increased day-time demand). Although this is attributed to a day-night rhythm in post-translational ion channel regulation in the heart’s pacemaker, the sinus node, by the autonomic nervous system, we investigated whether there is a day-night rhythm in transcription. RNAseq revealed that ~ 44% of the sinus node transcriptome (7134 of 16,387 transcripts) has a significant day-night rhythm. The data revealed the oscillating components of an intrinsic circadian clock. Presumably this clock (or perhaps the master circadian clock in the suprachiasmatic nucleus) is responsible for the rhythm observed in the transcriptional machinery, which in turn is responsible for the rhythm observed in the transcriptome. For example, there is a rhythm in transcripts responsible for the two principal pacemaker mechanisms (membrane and Ca2+ clocks), transcripts responsible for receptors and signalling pathways known to control pacemaking, transcripts from genes identified by GWAS as determinants of resting heart rate, and transcripts from genes responsible for familial and acquired sick sinus syndrome.

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The influence of brain metastases on the central nervous system effects of methylnaltrexone: a post hoc analysis of 3 randomized, double-blind studies

Supportive Care in Cancer ◽

10.1007/s00520-021-06070-7 ◽

2021 ◽

Author(s):

Darren M. Brenner ◽

Neal E. Slatkin ◽

Nancy Stambler ◽

Robert J. Israel ◽

Paul H. Coluzzi

Keyword(s):

Central Nervous System ◽

Nervous System ◽

Brain Metastases ◽

Cancer Patients ◽

Opioid Withdrawal ◽

Double Blind ◽

Post Hoc Analysis ◽

Pain Scores ◽

Opioid Receptor Antagonists ◽

Post Hoc

Abstract Purpose Peripherally acting μ-opioid receptor antagonists such as methylnaltrexone (MNTX, Relistor®) are indicated for the treatment of opioid-induced constipation (OIC). The structural properties unique to MNTX restrict it from traversing the blood-brain barrier (BBB); however, the BBB may become more permeable in patients with brain metastases. We investigated whether the presence of brain metastases in cancer patients compromises the central effects of opioids among patients receiving MNTX for OIC. Methods This post hoc analysis of pooled data from 3 randomized, placebo-controlled trials included cancer patients with OIC who received MNTX or placebo. Endpoints included changes from baseline in pain scores, rescue-free laxation (RFL) within 4 or 24 h of the first dose, and treatment-emergent adverse events (TEAEs), including those potentially related to opioid withdrawal symptoms. Results Among 356 cancer patients in the pooled population, 47 (MNTX n = 27; placebo n = 20) had brain metastases and 309 (MNTX n = 172; placebo n = 137) did not have brain metastases. No significant differences in current pain, worst pain, or change in pain scores from baseline were observed between patients treated with MNTX or placebo. Among patients with brain metastases, a significantly greater proportion of patients who received MNTX versus placebo achieved an RFL within 4 h after the first dose (70.4% vs 15.0%, respectively, p = 0.0002). TEAEs were similar between treatment groups and were generally gastrointestinal in nature and not related to opioid withdrawal. Conclusion Focal disruptions of the BBB caused by brain metastases did not appear to alter central nervous system penetrance of MNTX.

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Human and Human-Interfaced AI Interactions: Modulation of Human Male Autonomic Nervous System via Pupil Mimicry

Sensors ◽

10.3390/s21041028 ◽

2021 ◽

Vol 21 (4) ◽

pp. 1028

Author(s):

Catherine Spicer ◽

Prashanna Khwaounjoo ◽

Yusuf Ozgur Cakmak

Keyword(s):

Heart Rate ◽

Nervous System ◽

Parasympathetic Nervous System ◽

Pupil Dilation ◽

Physical Parameters ◽

Emotional States ◽

Virtual Humans ◽

Autonomic Functioning ◽

Technological Advances ◽

Pupil Constriction

Pupillary alterations in virtual humans induce neurophysiological responses within an observer. Technological advances have enabled rapid developments in artificial intelligence (AI), from verbal systems, to visual AI interfaces with the ability to express, and respond to emotional states of a user. Visual AI interfaces are able to change their physical parameters, such as pupil diameter. Pupillary changes can alter heart rate, however, effects on heart rate variability (HRV) are unknown. HRV, is an autonomic, non-conscious parameter which monitors sympathetic and parasympathetic nervous system (PNS) activity. N = 34 male participants aged between 19–33 were subjected to a number of conditions such as pupil dilation, constriction and blushing. The present research is the first to investigate the effects of virtual human interactions on human HRV. Outcomes of this study were obtained using eye tracking and HRV measurements. Pupil dilation relative to constriction presented in the female virtual partner induced a significant right pupillary diameter increase (p = 0.041) in human observers. Additionally, female virtual partner pupil constriction relative to dilation induced a significant increase in participants’ PNS HRV response (p = 0.036). These findings indicate the ability of a female virtual interaction partner to modulate parasympathetic autonomic functioning in young healthy male humans. This allows first insights into the effects of interacting with virtual AI interaction partners, on human autonomic functioning, and may aid development of future virtual humans, and their implementation into relevant clinical settings.

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Effects of exercise on cardiac autonomic modulation in children: literature update

Fisioterapia em Movimento ◽

10.1590/0103-5150.028.003.ar03 ◽

2015 ◽

Vol 28 (3) ◽

pp. 627-636 ◽

Cited By ~ 1

Author(s):

Gustavo Henrique de Oliveira Mondoni ◽

Luiz Carlos Marques Vanderlei ◽

Bruno Saraiva ◽

Franciele Marques Vanderlei

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

Nervous System ◽

Autonomic Nervous System ◽

Parasympathetic Nervous System ◽

Healthy Children ◽

Autonomic Modulation ◽

Healthy Development ◽

Autonomic Nervous ◽

Cardiac Autonomic Modulation

AbstractIntroduction It is known that physical exercise is beneficial and precipitates adjustments to the autonomic nervous system. However, the effect of exercise on cardiac autonomic modulation in children, despite its importance, is poorly investigated.Objective To bring together current information about the effects of exercise on heart rate variability in healthy and obese children.Methods The literature update was performed through a search for articles in the following databases; PubMed, PEDro, SciELO and Lilacs, using the descriptors “exercise” and “child” in conjunction with the descriptors “autonomic nervous system”, “sympathetic nervous system”, “parasympathetic nervous system” and also with no descriptor, but the key word of this study, “heart rate variability”, from January 2005 to December 2012.Results After removal of items that did not fit the subject of the study, a total of 9 articles were selected, 5 with healthy and 4 with obese children.Conclusion The findings suggest that exercise can act in the normalization of existing alterations in the autonomic nervous system of obese children, as well as serve as a preventative factor in healthy children, enabling healthy development of the autonomic nervous system until the child reaches adulthood.

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Hemodynamic Patterns and Spectral Analysis of Heart Rate Variability during Dialysis Hypotension

Journal of the American Society of Nephrology ◽

10.1681/asn.v10122577 ◽

1999 ◽

Vol 10 (12) ◽

pp. 2577-2584

Author(s):

MICHEL G. W. BARNAS ◽

WALTHER H. BOER ◽

HEIN A. KOOMANS

Keyword(s):

Heart Rate ◽

Nervous System ◽

Spectral Analysis ◽

Parasympathetic Nervous System ◽

Intradialytic Hypotension ◽

Intravascular Volume ◽

Autonomic Nervous System Activity ◽

System Activity ◽

Nervous System Activity ◽

Sympathetic Nervous

Abstract. Intradialytic hypotension, a major source of morbidity during hemodialysis and ultrafiltration, is often accompanied by paradoxical bradycardia. Relatively little is known about the sequential changes in autonomic nervous system activity up to and during the hypotensive episode. Continuous, beat-to-beat measurements of BP and heart rate were made during hemodialysis in patients prone (n = 8) and not prone (n = 11) to develop intradialytic hypotension. Off-line spectral analysis of heart rate variability (HRV) was performed to assess changes in autonomic nervous system activity during dialysis sessions both with and without hypotension. The low frequency (LF) component of HRV is thought to correlate with sympathetic nervous system activity, the high frequency (HF) component with that of the parasympathetic nervous system. In the sessions not complicated by symptomatic hypotension (n = 26), mean arterial BP (MAP) hardly fell, whereas heart rate increased from 77 ± 2 to 89 ± 5 bpm (P < 0.05). The LF component of HRV increased from 45.2 ± 5.0 normalized units (nu) to 59.9 ± 4.9 nu (P < 0.05), whereas the HF component fell from 54.8 ± 5.0 to 40.2 ± 4.4 nu (P < 0.05). These changes agree with compensatory baroreflex-mediated activation of the sympathetic nervous system (and suppressed parasympathetic activity) during ultrafiltration-induced intravascular volume depletion. In the sessions complicated by severe symptomatic hypotension (n = 22), the changes in heart rate and the results of spectral analysis of HRV were similar to those reported above up to the moment of sudden symptomatic (nausea, vomiting, dizziness, cramps) hypotension, whereas MAP had already fallen gradually from 94 ± 3 to 85 ± 3 mmHg (P < 0.05). The sudden further reduction in MAP (to 55 ± 2 mmHg, P < 0.02) was invariably accompanied by bradycardia (heart rate directly before hypotension 90 ± 2 bpm, during hypotension 69 ± 3 bpm, P < 0.002). The LF component of HRV fell from 62.8 ± 4.6 nu directly before to 40.0 ± 3.7 nu (P < 0.05) during hypotension, whereas the HF component increased from 37.9 ± 4.7 to 60.3 ± 3.7 nu (P < 0.05). These findings agree with activation of the cardiodepressor reflex, involving decreased sympathetic and increased parasympathetic nervous system activity, respectively. These findings indicate that activation of the sympatho-inhibitory cardiodepressor reflex (Bezold-Jarisch reflex), which is a physiologic response to a critical reduction in intravascular volume and cardiac filling, is the cause of sudden intradialytic hypotension.

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Abstract P161: Tai Chi Movements Bring On Parasympathetic Nerve Output As Indicated By Audible Bowel Sounds

Circulation ◽

10.1161/circ.143.suppl_1.p161 ◽

2021 ◽

Vol 143 (Suppl_1) ◽

Author(s):

Desuo Wang

Keyword(s):

Heart Rate ◽

Nervous System ◽

Sympathetic Nervous System ◽

Tai Chi ◽

Parasympathetic Nervous System ◽

Autonomic Nerve ◽

Parasympathetic Nerve ◽

Bowel Sounds ◽

Sympathetic Nervous ◽

Tai Chi Exercise

Tai Chi movements are unique exercise that can improve cognition, strength somatomotor coordination, and enhance autonomic nerve regulation on internal organ function. The mild increase in heart rate and/or slight sweat during and after practicing Tai Chi indicates the activation of the sympathetic nervous system. There is lack of evidence to show that Tai Chi exercise enhances the activity of parasympathetic nervous system though it has been claimed that practicing Tai Chi could do so. The author tested the hypothesis that Tai Chi exercise brings on an increase in parasympathetic nerve outputs (PNO). The PNO is evaluated by recording the bowel sounds using an audio recorder (Sony digital voice recorder ICD-PX Series) and the data analyses were done using NCH software (WavePad audio editor). The heart rate was simultaneously recorded using a fingertip pulse oximeter (Zacurate Pro Series 500DL) during Tai Chi exercise. All the data was repeatedly collected from a Tai Chi Master in a study period of 6 months. A total of 30 recordings were used to carry out the analysis. The audible bowel sounds occurred when the performer started to do the Ready-Movement of Yang-style Tai Chi. These Tai Chi induced-bowel sounds lasted from the beginning to the end of a set of movements (3-5 min for 24-moves style). The frequency of bowel sounds was in a range of 0.2 to 3.5 Hz. The average number of bowel sounds was approximately 2.5 sounds per Tai Chi Move. The intensity and frequency of the bowel sounds are not related to the change of the performer’s heart rate. In comparison, meditation or deep squat exercise performed by the Tai Chi master did not cause any changes in the bowel sounds. According to the autonomic innervation of the GI tract, increase of bowel movements is mediated by PNO. In conclusion, Tai Chi movements can simultaneously exercise skeletal muscles, sympathetic nervous system and parasympathetic nervous system. The enhancement of parasympathetic nervous system output by Tai Chi exercise is a valuable modality of physical exercise for wellness.

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Assessment of the impact of 10-day intermittent hypoxia on the autonomic control measured by heart rate variability

Physiology International ◽

10.1556/2060.105.2018.4.31 ◽

2018 ◽

Vol 105 (4) ◽

pp. 386-396 ◽

Cited By ~ 2

Author(s):

ZZ Taralov ◽

KV Terziyski ◽

PK Dimov ◽

BI Marinov ◽

SS Kostianev

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

Nervous System ◽

Parasympathetic Nervous System ◽

Autonomic Control ◽

Total Power ◽

Hypoxic Exposure ◽

Intermittent Hypoxic Training ◽

Parasympathetic Nervous System Activity ◽

The Impact

Purpose The purpose of this study is to establish the alterations in the activity of the autonomic nervous system (ANS) via heart rate variability (HRV) in subjects exposed to 1 h of exogenous hypoxia for 10 consecutive days. Methods Twelve healthy non-smoker males at mean age of 29.8 ± 7.4 (mean ± SD) breathed hypoxic air delivered through hypoxicator (FiО2 = 12.3% ± 1.5%) for 1 h in 10 consecutive days. Pulse oximetry and electrocardiography were monitored during the visit and HRV was calculated for the entire 1-h hypoxic period. Results Comparing the last hypoxic visit to the first, subjects had higher standard deviation of normal-to-normal interbeat intervals (SDNNs) (65.7 ± 32.5 vs. 81.1 ± 32.0 ms, p = 0.013) and root mean square of successive R–R interval difference (RMSSD) (58.1 ± 30.9 vs. 76.5 ± 34.6 ms, p = 0.029) as well as higher lnTotal power (8.1 ± 1.1 vs. 8.5 ± 0.9 ms2, p = 0.015) and high frequency (lnHF) (6.8 ± 1.3 vs. 7.5 ± 1.2 ms2, p = 0.05) and lower LF/HF (2.4 ± 1.4 vs. 1.5 ± 1.0, p = 0.026). Changes in saturation (87.0 ± 7.1 vs. 90.8 ± 5.0%, p = 0.039) and heart rate (67.1 ± 8.9 vs. 62.5 ± 6.0 beats/min, p = 0.040) were also observed. Conclusions Intermittent hypoxic training consisting of 1-h hypoxic exposure for 10 consecutive days could diminish the effects of acute exogenous hypoxia on the ANS characterized by an increased autonomic control (SDNN and total power) with augmentation of the parasympathetic nervous system activity (increased RMSSD and HF and decreased LF/HF). Therefore, it could be applied as a pre-acclimatization technique aiming at an increase in the autonomic control and oxygen saturation in subjects with upcoming sojourn to high altitude.

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Heart rate variability in children with type 1 diabetes mellitus

Revista Paulista de Pediatria ◽

10.1590/0103-0582201432215513 ◽

2014 ◽

Vol 32 (2) ◽

pp. 279-285 ◽

Cited By ~ 4

Author(s):

Camila Balsamo Gardim ◽

Bruno Affonso P. de Oliveira ◽

Aline Fernanda B. Bernardo ◽

Rayana Loch Gomes ◽

Francis Lopes Pacagnelli ◽

...

Keyword(s):

Diabetes Mellitus ◽

Heart Rate ◽

Heart Rate Variability ◽

Type 1 Diabetes ◽

Nervous System ◽

Type 1 Diabetes Mellitus ◽

Parasympathetic Nervous System ◽

Vagal Activity ◽

Mesh Terms

OBJECTIVE:To gather current information about the effects of type 1 diabetes mellitus on children's cardiac autonomic behavior.DATA SOURCES: The search of articles was conducted on PubMed, Ibecs, Medline, Cochrane, Lilacs, SciELO and PEDro databases using the MeSH terms: "autonomic nervous system", "diabetes mellitus", "child", "type 1 diabetes mellitus", "sympathetic nervous system" and "parasympathetic nervous system", and their respective versions in Portuguese (DeCS). Articles published from January 2003 to February 2013 that enrolled children with 9-12 years old with type 1 diabetes mellitus were included in the review.DATA SYNTHESIS: The electronic search resulted in four articles that approached the heart rate variability in children with type 1 diabetes mellitus, showing that, in general, these children present decreased global heart rate variability and vagal activity. The practice of physical activity promoted benefits for these individuals.CONCLUSIONS: Children with type 1 diabetes mellitus present changes on autonomic modulation, indicating the need for early attention to avoid future complications in this group.

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