scholarly journals Infant diet sets the tone for parasympathetic regulation of resting heart rate: Development of vagal tone from 3 months to 2 years

2013 ◽  
Vol 27 (S1) ◽  
Author(s):  
R T Pivik ◽  
A Andres ◽  
K Tennal ◽  
Y Gu ◽  
N Armbya ◽  
...  
Keyword(s):  
Heart Rate ◽  
Vagal Tone ◽  
Resting Heart Rate ◽  
Infant Diet ◽  
Parasympathetic Regulation ◽  
Rate Development

P4423Extreme bradycardia in athletes is due to intrinsic changes within the heart

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
M D Flannery ◽  
F Sully ◽  
K Janssens ◽  
G Morris ◽  
J Kalman ◽  
...  
Keyword(s):  
Heart Rate ◽  
Vagal Tone ◽  
Endurance Athletes ◽  
Valsalva Manoeuvre ◽  
Resting Heart Rate ◽  
Maximum Heart Rate ◽  
Vo2 Max ◽  
Heart Rates ◽  
Intrinsic Heart Rate ◽  
Autonomic Blockade

Abstract Background It is well known that athletes and in particular endurance athletes have lower resting heart rates than non-athletes. This has generally been considered a healthy adaptation. Traditionally this was thought be due to increased vagal tone. Several studies have shown that endurance athletes continue to have lower heart rates in the absence of autonomic influence suggesting bradycardia is due to intrinsic changes within the heart. A subset of endurance athletes have very low heart rates with Tour de France cyclists having described heart rates in the 30s. It is unclear whether in these elite athletes with very low heart rates the profound bradycardia is due to autonomic influence or intrinsic changes within the heart. Aim The aim of this study was to determine if extreme bradycardia in athletes is due to excess vagal tone or more profound intrinsic changes within the heart. Methods We recruited three cohorts for this study: non-athlete controls (NA), endurance athletes with a documented resting heart rate >40 (EA) and endurance athletes with a resting heart rate <40 (BA). All participants underwent baseline testing including ECG, echocardiography and VO2 max testing. All participants came back on a second occasion for treatment with dual autonomic blockade (DAB) to determine intrinsic heart rate in the following manner. After resting supine for five minutes resting heart rate was measured. Participants were then administered 0.04mg/kg of intravenous atropine. After five minutes participants were then administered 0.05mg/kg of intravenous metoprolol. This was repeated every five minutes until there was no further drop in heart rate or 0.2mg/kg had been administered. The resting heart rate at this stage was recorded as the intrinsic heart rate. Parasympathetic blockade was confirmed by lack of response to Valsalva manoeuvre and sympathetic blockade was confirmed by lack of response to metoprolol. VO2 max testing was then performed to determine maximum heart rate. Results 9 NA (7 male), 10 EA (8 male) and 5 BA (4 male) participated in this study. The average age was similar in all groups (NA 32.9y, EA 32.4y, BA 31.4y). The average resting heart rate was 71.7 in the NA group, 48.3 in the EA group and 41.6 in the BA group (p<0.05 for comparisons between all three groups). Following dual autonomic blockade resting heart rate was 86.0 in the NA group, 76.9 in the EA group and 64.4 in the BA group (p<0.05 for comparisons between all three groups). Maximum heart rate under DAB was 140.1 in the NA group, 138.0 in the EA group and 140.4 in the BA group. These differences were not significant. Conclusion In athletes with very low heart rates, bradycardia is due to more profound intrinsic changes within the heart. Acknowledgement/Funding NHMRC Project Grant

Effect of acetylcholinesterase inhibition with pyridostigmine on cardiac parasympathetic function in sedentary adults and trained athletes

2007 ◽  
Vol 293 (1) ◽  
pp. H86-H92 ◽  
Author(s):  
Thomas A. Dewland ◽  
Ana Silvia Androne ◽  
Forrester A. Lee ◽  
Rachel J. Lampert ◽  
Stuart D. Katz
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Frequency Domain ◽  
Heart Rate Recovery ◽  
Acetylcholinesterase Inhibition ◽  
Resting Heart Rate ◽  
Parasympathetic Tone ◽  
Resting Heart Rate Variability ◽  
Parasympathetic Function ◽  
Parasympathetic Regulation

Heart rate variability and postexercise heart rate recovery are used to assess cardiac parasympathetic tone in human studies, but in some cases these indexes appear to yield discordant information. We utilized pyridostigmine, an acetylcholinesterase inhibitor that selectively augments the parasympathetic efferent signal, to further characterize parasympathetic regulation of rest and postexercise heart rate. We measured time- and frequency-domain indexes of resting heart rate variability and postexercise heart rate recovery in 10 sedentary adults and 10 aerobically trained athletes after a single oral dose of pyridostigmine (30 mg) and matching placebo in randomized, double-blind, crossover trial. In sedentary adults, pyridostigmine decreased resting heart rate [from 66.7 (SD 12.6) to 58.1 beats/min (SD 7.6), P = 0.005 vs. placebo] and increased postexercise heart rate recovery at 1 min [from 40.7 (SD 10.9) to 45.1 beats/min (SD 8.8), P = 0.02 vs. placebo]. In trained athletes, pyridostigmine did not change resting heart rate or postexercise heart rate recovery when compared with placebo. Time- and frequency-domain indexes of resting heart rate variability did not differ after pyridostigmine versus placebo in either cohort and were not significantly associated with postexercise heart rate recovery in either cohort. The divergent effects of pyridostigmine on resting and postexercise measures of cardiac parasympathetic function in sedentary subjects confirm that these measures characterize distinct aspects of cardiac parasympathetic regulation. The lesser effect of pyridostigmine on either measure of cardiac parasympathetic tone in the trained athletes indicates that the enhanced parasympathetic tone associated with exercise training is at least partially attributable to adaptations in the efferent parasympathetic pathway.

Respiratory and Circulatory Responses of Rainbow Trout Larvae to Carbon Monoxide and to Hypoxia

1971 ◽  
Vol 55 (3) ◽  
pp. 683-694
Author(s):  
G. F. HOLETON
Keyword(s):  
Heart Rate ◽  
Carbon Monoxide ◽  
Rainbow Trout ◽  
Vagal Tone ◽  
Resting Heart Rate ◽  
Adult Fish ◽  
Cutaneous Respiration

1. Larval trout undergo a transition from cutaneous respiration to gill respiration which at 10°C is well advanced by the 18th day after hatching. 2. Resting heart rate of newly hatched trout increases during the first few days, stabilizes for a while, and then drops between the 9th and 18th day after hatching. This drop may be the result of establishment of ‘vagal tone’. 3. The basic breathing response of larval trout when hypoxic is an increase in fin movements and an increase in rate and amplitude of breathing, but breathing movements slow and weaken if environmental PO2 falls much below 40 mmHg. 4. With trout up to 8 days after hatching hypoxia causes a tachycardia. At very low PO2 levels there is a drop in heart rate and in the amount of blood pumped by the heart. Upon restoring oxygen to very hypoxic larvae, the heart rate recovers slowly, unlike the quick abolition of bradycardia of adult fish. It appears that up to the age of 8 days from hatching, trout do not have a functional bradycardia reflex associated with hypoxia. 5. The responses of larval trout to CO and to hypoxia, and of adult trout to CO, are similar in nature. It is proposed that the basic response to anoxaemia is an increase in breathing and circulation and that the adult bradycardia response to hypoxia is a superimposed mechanism which relates circulation to the quantity of oxygen presented to the gills.

Regional Frontal Lobe Response Magnitudes During Affective Shifting Covary With Resting Heart Rate Variability in Healthy Volunteers

2016 ◽  
Vol 30 (4) ◽  
pp. 165-174 ◽  
Author(s):  
Ryan Smith ◽  
John J.B. Allen ◽  
Julian F. Thayer ◽  
Richard D. Lane
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Healthy Subjects ◽  
Emotional Reactivity ◽  
Bold Signal ◽  
Resting Heart Rate ◽  
Functional Magnetic Resonance ◽  
Absolute Value ◽  
Cardiac Vagal Control ◽  
Resting Heart Rate Variability

Abstract. We hypothesized that in healthy subjects differences in resting heart rate variability (rHRV) would be associated with differences in emotional reactivity within the medial visceromotor network (MVN). We also probed whether this MVN-rHRV relationship was diminished in depression. Eleven healthy adults and nine depressed subjects performed the emotional counting stroop task in alternating blocks of emotion and neutral words during functional magnetic resonance imaging (fMRI). The correlation between rHRV outside the scanner and BOLD signal reactivity (absolute value of change between adjacent blocks in the BOLD signal) was examined in specific MVN regions. Significant negative correlations were observed between rHRV and average BOLD shift magnitude (BSM) in several MVN regions in healthy subjects but not depressed subjects. This preliminary report provides novel evidence relating emotional reactivity in MVN regions to rHRV. It also provides preliminary suggestive evidence that depression may involve reduced interaction between the MVN and cardiac vagal control.

Resting Heart Rate and Right Frontal Lobe Functioning in Trauma Survivors

2008 ◽  
Author(s):  
Christopher Immel ◽  
James Hadder ◽  
Michael Knepp ◽  
Chad Stephens ◽  
Ryoichi Noguchi ◽  
...  
Keyword(s):  
Heart Rate ◽  
Frontal Lobe ◽  
Trauma Survivors ◽  
Resting Heart Rate ◽  
Frontal Lobe Functioning
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