scholarly journals The Relationship Between Dive and Pre-Dive Heart Rates in Restrained and Free Dives by Diving Ducks

1987 ◽  
Vol 127 (1) ◽  
pp. 333-348 ◽  
Author(s):  
R. A. FURILLA ◽  
DAVID R. JONES
Keyword(s):  
Heart Rate ◽  
Marked Effect ◽  
Sympathetic Nerves ◽  
Vagal Activity ◽  
Similar Increase ◽  
Lower Heart Rate ◽  
Diving Ducks ◽  
Cardiac Responses ◽  
Cardiac Control ◽  
The Relationship

Dive heart rate was plotted against pre-dive heart rate in forced and voluntary dives and dabbles by restrained and free ducks. The relationship between pre-dive heart rate and the cardiac interval occurring just before or coincident with submersion (first cardiac interval) and the heart rate after 2–5 s submergence (stabilized heart rate) was emphasized. Stabilized heart rate in forced dives by restrained ducks at rest and at the end of a bout of exercise, and heart rate in voluntary dives and dabbles were linearly related on a plot of dive heart rate against the logarithm of predive heart rate. Even the heart rate occurring 2–5 s after ducks were ‘trapped’ under water, compared with the rate immediately before ‘trapping’, fitted on this line. The line was described by the equation y = - 451 + 2461ogx where y is dive (or trapped) and × is pre-dive (or pre-trap) heart rate (r2 = 0.98). The relationship was unaltered by β-blockade with propranolol. Furthermore, nasal blockade with Xylocaine, O2 breathing before submersion, and arterial baroreceptor denervation had no marked effect on the relationship in voluntary and trapped dives. Implantation of stimulating electrodes bilaterally on the cut distal ends of vagal and cardiac sympathetic nerves suggested that in all these dives there is a similar increase in the level of efferent vagal activity during submersion. However, the first cardiac interval in voluntary dives represents a much lower heart rate and therefore higher level of vagal activity. The present data suggest that there is considerable psychogenic modulation of cardiac responses in voluntary diving and only in forced dives, by restrained animals, is cardiac control largely reflexogenic.

Forced and voluntary diving in ducks: cardiovascular adjustments and their control

1988 ◽  
Vol 66 (1) ◽  
pp. 75-83 ◽  
Author(s):  
David R. Jones ◽  
R. A. Furilla ◽  
M. R. A. Heieis ◽  
G. R. J. Gabbott ◽  
F. M. Smith
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Cardiovascular Responses ◽  
Cardiac Response ◽  
Vagal Activity ◽  
Diving Ducks ◽  
Cardiac Responses ◽  
Hind Limbs ◽  
Dabbling Duck ◽  
Arterial Chemoreceptor

Diving ducks submerge voluntarily for less than 1 min yet, in forced dives in the laboratory, redhead ducks can endure at least 8 min underwater. This is much longer than a dabbling duck of the same body mass can endure and is a result of the quicker onset of oxygen-conserving cardiovascular responses in divers. Oxygen conservation during forced dives is indicated by a profound bradycardia as blood flow is restricted to cerebral and central cardiovascular areas. In voluntary dives, on the other hand, heart rate is frequently above resting rates, and blood flow is preferentially directed to the working muscles of the hind limbs. Profound bradycardia only occurs in unrestrained ducks when they are trapped underwater. Since leg movements cease within 30 s after ducks are trapped, blood flow must at that time be directed away from the working muscles, as in the "classical" oxygen-conserving dive response. Cardiovascular adjustments to forced diving are caused by stimulation of nasal receptors in diving ducks. In dabblers, arterial chemoreceptor stimulation is crucial to the response, although an intact barostatic system may be necessary for development of profound bradycardia. Baroreceptors are essential for the cardiac response observed when dabblers are trained to dive for food, although neither baro-, chemo-, nor naso-receptors appear to have much to do with the cardiac adjustments to voluntary submergence in diving ducks. Nevertheless, in divers, cardiac adjustments to dabbling and forced, voluntary, and trapped dives are linearly related on a plot of dive (trapped) against the logarithm of predive (pretrap) heart rate. This relationship is due to a similar increase in vagal activity, of some 50% of maximum, in all types of diving manoeuvers. Phychogenic factors, long thought to be important in cardiac responses to forced diving, would appear to underpin this relationship.

Adrenal contribution to cardiac responses elicited by acute hypoxia in piglets

1980 ◽  
Vol 239 (6) ◽  
pp. H751-H755 ◽  
Author(s):  
J. C. Lee ◽  
J. C. Werner ◽  
S. E. Downing
Keyword(s):  
Heart Rate ◽  
Adrenal Glands ◽  
Acute Hypoxia ◽  
Cardiac Contractility ◽  
Sympathetic Nerves ◽  
Left Ventricular ◽  
Cardiac Work ◽  
Ganglionic Blockade ◽  
Cardiac Responses

The adrenal contribution to cardiac responses elicited by acute hypoxia was assessed in 16 piglets, 1-12 wks old, anesthetized with pentobarbital (30 mg/kg). External cardiac work was held constant and parasympathetic blockade was produced in each animal with atropine (1 mg). Hypoxia was produced by addition of N2 to the respirator. In a sham-adrenalectomy group (n = 6) left ventricular (LV) dP/dtmax increased significantly during hypoxia (PaO2 approximately 30 mmHg) to 3,680 +/- 414 mmHg/s from control values of 2,686 +/- 317 mmHg/s (P < 0.01). Heart rate rose from 171 +/- 6 to 186 +/- 7 beats/min (P < 0.02). These responses were not significantly altered by ganglionic blockade with trimethaphan camsylate (0.5 mg x kg-1 x min-1). Equally large increases of LV dP/dtmax appeared when heart rate was held constant by pacing. beta-Adrenoreceptor blockade with practolol (4 mg/kg) sharply reduced but did not eliminate the response. In contrast, no changes in LV dP/dtmax or heart rate were observed during hypoxia in adrenalectomized piglets (n = 6). These findings indicate that the increased cardiac contractility during acute hypoxia in piglets is dependent on the integrity of the adrenal glands and that there is minimal contribution from cardiac sympathetic nerves.

scholarly journals The contribution of nasal receptors to the cardiac response to diving in restrained and unrestrained redhead ducks (Aythya americana)

1986 ◽  
Vol 121 (1) ◽  
pp. 227-238 ◽  
Author(s):  
R. A. Furilla ◽  
D. R. Jones
Keyword(s):  
Heart Rate ◽  
Local Anaesthesia ◽  
Cardiac Response ◽  
Dabbling Ducks ◽  
Diving Ducks ◽  
Cardiac Responses ◽  
Aythya Americana ◽  
Dabbling Duck ◽  
Redhead Ducks ◽  
A Minor

In restrained redhead ducks, forced submergence caused heart rate to fall from 100 +/− 3 beats min-1 (mean +/− S.E.M., N = 12) to a stable underwater rate of 35 +/− 4 beats min-1 (N = 12) within 5 s after submergence. Bradycardia was unaffected by breathing oxygen before a dive, but was virtually eliminated by local anaesthesia of the narial region. In contrast, in a dabbling duck (Anas platyrhynchos) bradycardia in short dives was eliminated by breathing oxygen before a dive. In unrestrained diving, on a man-made pond, heart rate in redheads diving voluntarily (y) was related to pre-dive heart rate (x) by the equation y = 76 + 0.29 +/− 0.05x +/− 17 (r2 = 0.71). Chasing, to induce submergence, had variable effects on this relationship. Local anaesthesia of the narial region inhibited voluntary diving but heart rates in chase-induced dives after nasal blockade were significantly higher, by 10–30%, than those obtained from untreated ducks in chase-induced dives. Breathing oxygen before voluntary dives had no apparent effect on heart rate after 2–5 s submergence. Voluntary head submersion by dabbling ducks caused no change in heart rate. We conclude that nasal receptors make only a minor contribution to cardiac responses in unrestrained dives, compared with forced dives, in diving ducks. Furthermore, these results show that little can be learned about cardiac responses in free diving ducks from studies of forced dives in dabblers or divers.

500 Late-Breaking: Heart Rate During Exercise Is Positively Correlated with State IV Mitochondrial Respiration in the Equine Skeletal Muscle

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 105-106
Author(s):  
Mia Y Kawaida ◽  
Oh-Sung Kwon ◽  
Ahram Anh ◽  
Amanda S Reiter ◽  
Nicole M Tillquist ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Heart Rate ◽  
Oxidative Phosphorylation ◽  
Mitochondrial Respiration ◽  
Recovery Period ◽  
Proton Leak ◽  
Semitendinosus Muscle ◽  
Exercise Tests ◽  
Cardiac Responses ◽  
The Relationship

Abstract Mitochondria are critical for oxidative phosphorylation in skeletal muscle, especially in athletic species such as the horse. Mitochondrial respiration increases with physical exercise, but the relationship between mitochondrial respiration and cardiovascular functions are not well described in the horse. The objective of this study was to determine if there is a relationship between heart rate (HR) during and after submaximal exercise tests (SETs) and skeletal muscle mitochondrial respiration in polo ponies. We hypothesized that horses with greater maximum HR and average HR during the exercise tests would have greater mitochondrial respiration in skeletal muscle. Twelve fit polo ponies (14.8 ± 1.7 years old, 10 mares and 2 geldings) were equipped with Polar equine heart rate monitors (Polar Electro Inc., Lake Success, NY) and underwent 26-minute SETs designed to mimic a polo chukker followed by a 30-minute recovery period. Muscle biopsy samples from the semitendinosus muscle were taken 2 weeks prior to the SET to determine mitochondrial oxygen consumption using the Oroboros O2k high-resolution respirometer (Oroboros Instruments, Innsbruck, Austria). Data were analyzed using the PROC CORR procedure (SAS Inst. Inc., Cary, NC). Correlations were considered strong at r &gt; 0.6 and significant at P &lt; 0.05. Maximum HR during SET and state IV respiration were positively correlated (P = 0.02, r = 0.68). Average HR during SET and state IV respiration were also positively correlated (P = 0.01, r = 0.72). However, correlations between maximum and average HR and state III respiration were not as strong (P ≥ 0.05, r &lt; 0.6). These data suggest that state IV mitochondrial respiration (proton leak) in equine skeletal muscle may impact cardiac responses to high-intensity exercise. Horses with higher HR during exercise may have less efficient oxidative phosphorylation, resulting in earlier fatigue and/or greater formation of reactive oxygen species resulting from proton leak.

Effects of increased training load on vagal-related indexes of heart rate variability: a novel sleep approach

2004 ◽  
Vol 287 (6) ◽  
pp. H2813-H2818 ◽  
Author(s):  
M. Buchheit ◽  
C. Simon ◽  
F. Piquard ◽  
J. Ehrhart ◽  
G. Brandenberger
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Slow Wave Sleep ◽  
Training Load ◽  
Vagal Activity ◽  
Lower Heart Rate ◽  
Sleep Parameters ◽  
Recording Conditions ◽  
Young Subjects ◽  
Better Than

There is little doubt that moderate training improves cardiac vagal activity and thus has a cardioprotective effect against lethal arrhythmias. Our purpose was to learn whether a higher training load would further increase this beneficial effect. Cardiac autonomic control was inferred from heart rate variability (HRV) and analyzed in three groups of young subjects (24.5 ± 3.0 yr) with different training states in a period free of stressful stimuli or overload. HRV was analyzed in 5-min segments during slow-wave sleep (SWS, a parasympathetic state that offers high electrocardiographic stationarity) and compared with data collected during quiet waking periods in the morning. Sleep parameters, fatigue, and stress levels checked by questionnaire were identical for all three groups with no signs of overtraining in the highly trained (HT) participants. During SWS, a significant ( P < 0.05) increase in absolute and normalized vagal-related HRV indexes was observed in moderately trained (MT) individuals compared with sedentary (Sed) subjects; this increase did not persist in HT athletes. During waking periods, most of the absolute HRV indexes indistinctly increased in MT individuals compared with controls ( P < 0.05) but did not increase in HT athletes. Normalized spectral HRV indexes did not change significantly among the three groups. Heart rate was similar for MT and Sed subjects but was significantly ( P < 0.05) lower in HT athletes under both recording conditions. These results indicate that SWS discriminates the state of sympathovagal balance better than waking periods. A moderate training load is sufficient to increase vagal-related HRV indexes. However, in HT individuals, despite lower heart rate, vagal-related HRV indexes return to Sed values even in the absence of competition, fatigue, or overload.

Correlation of depth and heart rate in harbour seal pups

2004 ◽  
Vol 82 (7) ◽  
pp. 1147-1156 ◽  
Author(s):  
J L Hicks ◽  
R J O'Hara Hines ◽  
J F Schreer ◽  
M O Hammill
Keyword(s):  
Heart Rate ◽  
River Estuary ◽  
Dive Depth ◽  
Dive Duration ◽  
Harbour Seal ◽  
Cardiac Responses ◽  
Cardiac Control ◽  
Apparent Relationship ◽  
St Lawrence River ◽  
Mean Heart Rate

Harbour seal (Phoca vitulina L., 1758) pups are aquatically active from birth and have been shown to develop increased cardiac control throughout the nursing period. In an attempt to quantify and compare these developmental changes, data previously collected on pups in the St. Lawrence River estuary, Quebec, Canada, were analyzed. Time–depth recorders and heart-rate recorders were employed on eight pups to obtain depth and heart-rate measurements simultaneously. Analyses involved partitioning the data into intervals of surface–dive–surface. These intervals were then allocated into nine consecutive segments: presurface, predive surface, descent, prebottom, bottom, postbottom, ascent, postdive surface, and postsurface. Mean heart rate for each segment was then correlated with the mean depth per segment and overall dive duration. With increasing dive depth, a decrease in heart-rate variability with age was observed. There was no apparent relationship between mean heart rate during the dive and overall dive duration. The proportion of time spent in the lower heart-rate mode was observed to increase with age during most phases of a dive. Relative changes in mean heart rate between consecutive dive segments indicated an initial decrease in mean heart rate prior to submersion and an increasing trend before surfacing. These findings indicate that harbour seal pups develop increased cardiac control prior to weaning and that anticipatory cardiac responses to diving and surfacing (bradycardia and tachycardia, respectively) may be evident.

scholarly journals Reduced vagal tone in women with endometriosis and auricular vagus nerve stimulation as a potential therapeutic approach

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Meihua Hao ◽  
Xishi Liu ◽  
Peijing Rong ◽  
Shaoyuan Li ◽  
Sun-Wei Guo
Keyword(s):  
Heart Rate ◽  
Vagus Nerve Stimulation ◽  
Therapeutic Potential ◽  
Vagal Tone ◽  
Sympathetic Nerves ◽  
Vagal Activity ◽  
Autonomic Balance ◽  
Vagus Nerves ◽  
Lesion Development

AbstractSensory and sympathetic nerves have been shown to promote the progression of endometriosis through the release of neuromediators and the lesional activation of respective receptors. The role of vagus nerves (VN) in lesional progression, however, is completely unclear, despite the signs suggestive of increased sympathetic tone in women with endometriosis. This study was undertaken to investigate whether VN plays any role in the progression of endometriosis. We recruited 45 patients with endometriosis and 42 healthy women, who were given electrocardiogram test and their heart rate variability was evaluated. In addition, three prospective, and randomized mouse experiments were conducted that evaluated, respectively, the effect of vagotomy, the effect of VN stimulation (VNS), and the therapeutic potential of VNS after the endometriosis was well established. All lesions were excised, weighed, and processed for immunohistochemistry and histochemistry analysis of select markers for lesional progression and fibrosis. We found that endometriosis patients exhibited reduced vagal activity as compared with controls, indicative of disrupted autonomic balance. Vagotomy increased while VNS decreased the lesion weight as compared with control mice, concomitant with more progressive and retarded lesion development and fibrogenesis, respectively. In addition, VNS demonstrated promising therapeutic effect, as evidenced by significantly reduced lesion weight, more attenuated lesional progression concomitant with improved hyperalgesia. Taken together, our data indicate that VN activity may play a dampening role in the progression of endometriosis. Consequently, boosting the VN activity may have therapeutic potentials for patients with endometriosis.

scholarly journals Subjective Happiness Is Associated with Objectively Evaluated Sleep Efficiency and Heart Rate during Sleep: An Exploratory Study Using Non-Contact Sheet Sensors

2020 ◽  
Vol 12 (11) ◽  
pp. 4630
Author(s):  
Hisayoshi Okamura ◽  
Kengo Mihara ◽  
Akira Tsuda ◽  
Toshihiro Morisaki ◽  
Yoshiyuki Tanaka ◽  
...  
Keyword(s):  
Heart Rate ◽  
Sleep Onset ◽  
Sleep Efficiency ◽  
Sleep Onset Latency ◽  
Subjective Happiness ◽  
Onset Latency ◽  
Lower Heart Rate ◽  
Subjective Sleep ◽  
Subjective Happiness Scale ◽  
The Relationship

The objective of this study was to explore the relationship between subjective happiness and subjective and objective sleep. The participants were 24 healthy university students (11 males, 13 females; mean age 22.4 ± 2.1). Their subjective happiness was measured by the Japanese Subjective Happiness Scale (JSHS). Furthermore, their subjective and objective sleep evaluation was measured by Ogri-Shirakawa-Azumi sleep inventory MA version (OSA-MA) and a non-contact sheet sensor (SS). The results indicated that participants with higher subjective happiness had objectively shorter sleep onset latency, higher sleep efficiency, and lower heart rate during sleep. On the other hand, no such correlations were found between subjective sleep evaluation with OSA and subjective happiness. These results suggest that subjective happiness is related with the ability to more easily fall asleep and better sleep efficiency.

Note on Relation of Autonomic Perception to Voluntary Control of Heart Rate

1975 ◽  
Vol 40 (2) ◽  
pp. 533-534 ◽  
Author(s):  
Kirk R. Blankstein
Keyword(s):  
Heart Rate ◽  
Voluntary Control ◽  
Lower Heart Rate ◽  
Cardiac Control ◽  
Autonomic Perception

Relationships between subscores of the Autonomic Perception Questionnaire and ability to raise and lower heart rate voluntarily were examined in 40 subjects. Subscores which reflected general autonomic awareness in anxiety and pleasure states were not predictive of degree of cardiac control, while the subscore specific to reported awareness of heart functioning during pleasure states only was positively correlated with ability to raise heart rate.

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