scholarly journals Extreme bradycardia and tachycardia in the world’s largest animal

2019 ◽  
Vol 116 (50) ◽  
pp. 25329-25332 ◽  
Author(s):  
J. A. Goldbogen ◽  
D. E. Cade ◽  
J. Calambokidis ◽  
M. F. Czapanskiy ◽  
J. Fahlbusch ◽  
...  
Keyword(s):  
Heart Rate ◽  
Large Diameter ◽  
Large Body ◽  
Fold Increase ◽  
Oxygen Depletion ◽  
Blue Whale ◽  
Heart Rates ◽  
Physiological Limits ◽  
Low Mass ◽  
Lunge Feeding

The biology of the blue whale has long fascinated physiologists because of the animal’s extreme size. Despite high energetic demands from a large body, low mass-specific metabolic rates are likely powered by low heart rates. Diving bradycardia should slow blood oxygen depletion and enhance dive time available for foraging at depth. However, blue whales exhibit a high-cost feeding mechanism, lunge feeding, whereby large volumes of prey-laden water are intermittently engulfed and filtered during dives. This paradox of such a large, slowly beating heart and the high cost of lunge feeding represents a unique test of our understanding of cardiac function, hemodynamics, and physiological limits to body size. Here, we used an electrocardiogram (ECG)-depth recorder tag to measure blue whale heart rates during foraging dives as deep as 184 m and as long as 16.5 min. Heart rates during dives were typically 4 to 8 beats min−1 (bpm) and as low as 2 bpm, while after-dive surface heart rates were 25 to 37 bpm, near the estimated maximum heart rate possible. Despite extreme bradycardia, we recorded a 2.5-fold increase above diving heart rate minima during the powered ascent phase of feeding lunges followed by a gradual decrease of heart rate during the prolonged glide as engulfed water is filtered. These heart rate dynamics explain the unique hemodynamic design in rorqual whales consisting of a large-diameter, highly compliant, elastic aortic arch that allows the aorta to accommodate blood ejected by the heart and maintain blood flow during the long and variable pauses between heartbeats.

scholarly journals HEAR: Approach for Heartbeat Monitoring with Body Movement Compensation by IR-UWB Radar

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 3077 ◽  
Author(s):  
Wenfeng Yin ◽  
Xiuzhu Yang ◽  
Lei Li ◽  
Lin Zhang ◽  
Nattapong Kitsuwan ◽  
...  
Keyword(s):  
Heart Rate ◽  
Body Movement ◽  
Large Body ◽  
Ultra Wideband ◽  
Heart Rate Variability Analysis ◽  
Mean Deviation ◽  
Fast Time ◽  
Heart Rates ◽  
Mode Decomposition ◽  
Wideband Radar

Further applications of impulse radio ultra-wideband radar in mobile health are hindered by the difficulty in extracting such vital signals as heartbeats from moving targets. Although the empirical mode decomposition based method is applied in recovering waveforms of heartbeats and estimating heart rates, the instantaneous heart rate is not achievable. This paper proposes a Heartbeat Estimation And Recovery (HEAR) approach to expand the application to mobile scenarios and extract instantaneous heartbeats. Firstly, the HEAR approach acquires vital signals by mapping maximum echo amplitudes to the fast time delay and compensating large body movements. Secondly, HEAR adopts the variational nonlinear chirp mode decomposition in extracting instantaneous frequencies of heartbeats. Thirdly, HEAR extends the clutter removal method based on the wavelet decomposition with a two-parameter exponential threshold. Compared to heart rates simultaneously collected by electrocardiograms (ECG), HEAR achieves a minimum error rate 4.6% in moving state and 2.25% in resting state. The Bland–Altman analysis verifies the consistency of beat-to-beat intervals in ECG and extracted heartbeat signals with the mean deviation smaller than 0.1 s. It indicates that HEAR is practical in offering clinical diagnoses such as the heart rate variability analysis in mobile monitoring.

scholarly journals Heart Rate–Induced Myocardial Ca 2+ Retention and Left Ventricular Volume Loss in Patients With Heart Failure With Preserved Ejection Fraction

2020 ◽  
Vol 9 (17) ◽  
Author(s):  
Daniel N. Silverman ◽  
Mehdi Rambod ◽  
Daniel L. Lustgarten ◽  
Robert Lobel ◽  
Martin M. LeWinter ◽  
...  
Keyword(s):  
Heart Failure ◽  
Heart Rate ◽  
Ejection Fraction ◽  
Sinus Rhythm ◽  
Left Ventricular ◽  
Atrial Pacing ◽  
Preserved Ejection Fraction ◽  
Volume Loss ◽  
Heart Rates ◽  
Patients With Heart Failure

Background Increases in heart rate are thought to result in incomplete left ventricular (LV) relaxation and elevated filling pressures in patients with heart failure with preserved ejection fraction (HFpEF). Experimental studies in isolated human myocardium have suggested that incomplete relaxation is a result of cellular Ca 2+ overload caused by increased myocardial Na + levels. We tested these heart rate paradigms in patients with HFpEF and referent controls without hypertension. Methods and Results In 22 fully sedated and instrumented patients (12 controls and 10 patients with HFpEF) in sinus rhythm with a preserved ejection fraction (≥50%) we assessed left‐sided filling pressures and volumes in sinus rhythm and with atrial pacing (95 beats per minute and 125 beats per minute) before atrial fibrillation ablation. Coronary sinus blood samples and flow measurements were also obtained. Seven women and 15 men were studied (aged 59±10 years, ejection fraction 61%±4%). Patients with HFpEF had a history of hypertension, dyspnea on exertion, concentric LV remodeling and a dilated left atrium, whereas controls did not. Pacing at 125 beats per minute lowered the mean LV end‐diastolic pressure in both groups (controls −4.3±4.1 mm Hg versus patients with HFpEF −8.5±6.0 mm Hg, P =0.08). Pacing also reduced LV end‐diastolic volumes. The volume loss was about twice as much in the HFpEF group (controls −15%±14% versus patients with HFpEF −32%±11%, P =0.009). Coronary venous [Ca 2+ ] increased after pacing at 125 beats per minute in patients with HFpEF but not in controls. [Na + ] did not change. Conclusions Higher resting heart rates are associated with lower filling pressures in patients with and without HFpEF. Incomplete relaxation and LV filling at high heart rates lead to a reduction in LV volumes that is more pronounced in patients with HFpEF and may be associated with myocardial Ca 2+ retention.

Heart Rate and Performance in Manual Missile Guidance

1971 ◽  
Vol 32 (2) ◽  
pp. 352-354
Author(s):  
Bengt Bergstroem ◽  
Peter Arnberg
Keyword(s):  
Heart Rate ◽  
Performance Data ◽  
Tracking Performance ◽  
Missile Guidance ◽  
Heart Rates ◽  
Laboratory Conditions ◽  
Stress Studies ◽  
And Performance

Earlier stress studies under laboratory conditions show that heart rates from 100 to 110 bpm are associated with significant decrements in missile-tracking performance. Data from real missile tracking by 8 operators with no stress deliberately induced indicate, however, that performance is unaffected up to 135 bpm, and only moderately affected in the 135- to 170-bpm region. The disagreement between the two sets of results highlights the difficulties in generalizing from stress experiments.

Stress level in wild harbour porpoises (Phocoena phocoena) during satellite tagging measured by respiration, heart rate and cortisol

2009 ◽  
Vol 89 (5) ◽  
pp. 885-892 ◽  
Author(s):  
I.G. Eskesen ◽  
J. Teilmann ◽  
B.M. Geertsen ◽  
G. Desportes ◽  
F. Riget ◽  
...  
Keyword(s):  
Heart Rate ◽  
Respiration Rate ◽  
Serum Cortisol ◽  
Phocoena Phocoena ◽  
Heart Rates ◽  
Stress Effects ◽  
Respiration Rates ◽  
Stressed Animal ◽  
Cortisol Levels ◽  
Satellite Tagging

During satellite tagging of harbour porpoises (Phocoena phocoena), heart rate, respiration rate and cortisol value were measured to evaluate stress effects during handling and tagging. Respiration rates were obtained using video recordings, heart rates were recorded and serum cortisol levels were analysed from blood samples. Differences in heart rates, respiration rates and cortisol levels before and during the tagging events were investigated. An overall significant decrease of 31.5% in respiration rate was found during the tagging event period, while mature porpoises respired significantly more often than immature individuals. Though significant differences in heart rates were found for some individuals, no general significant change for all animals was detected. We found no correlation between cortisol concentration and either heart rate or respiration rate, nor did we find any relationships between cortisol and month of year, sex and body length. As high individual variations occurred in response to tagging of harbour porpoises, it is not possible to give general advice based on the factors investigated, on how to reduce stress during handling. However, pouring water over the animal and lowering it into the water seem to stabilize a stressed animal. Therefore, general precaution and individual judgement based on experience is essential when handling wild harbour porpoises.

Anticipatory, exercise, and recovery heart rates of girls as affected by four running events

1964 ◽  
Vol 19 (5) ◽  
pp. 853-856 ◽  
Author(s):  
Vera Skubic ◽  
Jane Hilgendorf
Keyword(s):  
Heart Rate ◽  
Cardiac Function ◽  
Heart Rate Response ◽  
Heart Rates

The heart rate response to running various distances was studied using five highly trained girls as subjects. A telemetering instrument was employed so that the testing could be done under actual sport conditions. The findings indicated that 1) the anticipatory heart rate just prior to exercise represented 59% of the total adjustment to exercise, 2) the heart rates during exercise were 2.5 times the resting values, and 3) heart rates observed at the end of the 220-, 440-, 880-yard, and mile events were simila cardiac function; exercise Submitted on October 22, 1963

scholarly journals How well are heart rates measured by pulse oximeters and electronic sphygmomanometers? Practice-based evidence from an observational study of acutely ill medical patients during hospital admission

2019 ◽  
Vol 18 (3) ◽  
pp. 144-147
Author(s):  
Mary Rimbi ◽  
◽  
Immaculate Nakitende ◽  
Teopista Namujwiga ◽  
John Kellett ◽  
...  
Keyword(s):  
Heart Rate ◽  
Observational Study ◽  
Hospital Admission ◽  
Pulse Oximeter ◽  
Medical Patients ◽  
Limits Of Agreement ◽  
Heart Rates ◽  
Electrocardiogram Ecg ◽  
Pulse Oximeters

Background: heart rates generated by pulse oximeters and electronic sphygmomanometers in acutely ill patients may not be the same as those recorded by ECG Methods: heart rates recorded by an oximeter and an electronic sphygmomanometer were compared with electrocardiogram (ECG) heart rates measured on acutely ill medical patients. Results: 1010 ECGs were performed on 217 patients while they were in the hospital. The bias between the oximeter and the ECG measured heart rate was -1.37 beats per minute (limits of agreement -22.6 to 19.9 beats per minute), and the bias between the sphygmomanometer and the ECG measured heart rate was -0.14 beats per minute (limits of agreement -22.2 to 21.9 beats per minute). Both devices failed to identify more than half the ECG recordings that awarded 3 NEWS points for heart rate. Conclusion: Heart rates of acutely ill patients are not reliably measured by pulse oximeter or electronic sphygmomanometers.

Learned Control of Heart Rate and Blood Pressure

1971 ◽  
Vol 33 (1) ◽  
pp. 219-226 ◽  
Author(s):  
Michael Hnatiow
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Systolic Blood Pressure ◽  
Blood Pressure Variability ◽  
Visual Display ◽  
Waveform Analysis ◽  
Target Range ◽  
Heart Rates ◽  
Systolic Blood Pressure Variability ◽  
Continuous Measures

Cardiac rate-variability control and an initial demonstration of systolic blood-pressure variability control using visual feedback of physiological information were examined. Continuous measures of respiration, heart rate, EXG waveform analysis, and systolic blood pressure were obtained for both experimental groups and for yoked controls who saw the same visual display as the experimental Ss. Ss successful at reducing heart-rate variability showed clear changes in the P-R wave relationships of the EKG, indicating possible direct attempts to manipulate heart rate so as to reduce variability. Ss controlling blood-pressure variability who had high heart rates were more successful in reducing variability than those with low rates, possibly because of differential feedback to Ss with high and low heart rates. In addition, apparently as a reaction to E's adjustment of the visual target range, experimental Ss showed decreases in mean blood-pressure levels.

Stability of Heart Rate at Physiological Thresholds Between Temperate and Heat Stress Environments in Endurance-Trained Males

2020 ◽  
pp. 1-4
Author(s):  
Ed Maunder ◽  
Daniel J. Plews ◽  
Fabrice Merien ◽  
Andrew E. Kilding
Keyword(s):  
Heart Rate ◽  
Heat Stress ◽  
Relative Humidity ◽  
Blood Lactate ◽  
Endurance Athletes ◽  
Heart Rates ◽  
Stress Environments ◽  
Positive Correlations ◽  
Hot Environments ◽  
Stress Training

Many endurance athletes perform specific blocks of training in hot environments in “heat stress training camps.” It is not known if physiological threshold heart rates measured in temperate conditions are reflective of those under moderate environmental heat stress. A total of 16 endurance-trained cyclists and triathletes performed incremental exercise assessments in 18°C and 35°C (both 60% relative humidity) to determine heart rates at absolute blood lactate and ventilatory thresholds. Heart rate at fixed blood lactate concentrations of 2, 3, and 4 mmol·L−1 and ventilatory thresholds were not significantly different between environments (P > .05), despite significant heat stress-induced reductions in power output of approximately 10% to 17% (P < .05, effect size = 0.65–1.15). The coefficient of variation for heart rate at these blood lactate concentrations (1.4%−2.9%) and ventilatory thresholds (2.3%−2.7%) between conditions was low, with significant strong positive correlations between measurements in the 2 environments (r = .92–.95, P < .05). These data indicate heart rates measured at physiological thresholds in temperate environments are reflective of measurements taken under moderate environmental heat stress. Therefore, endurance athletes embarking on heat stress training camps can use heart rate–based thresholds ascertained in temperate environments to prescribe training under moderate environmental heat stress.

Music-Assisted Training for Dart Throwing Novices: Post-Training Effects on Heart Rate and Performance Accuracy

2021 ◽  
pp. 003151252110506
Author(s):  
Ivor T. H. Tso ◽  
James C. L. Law ◽  
Thomson W. L. Wong
Keyword(s):  
Heart Rate ◽  
Control Group ◽  
Heart Rates ◽  
Performance Accuracy ◽  
Throwing Accuracy ◽  
Different Types ◽  
Dart Throwing ◽  
Post Test ◽  
And Performance ◽  
Athletes Heart

While previous research has suggested that lowering athletes’ heart rates can enhance sports performance, it is unknown whether slow-paced music might induce a lower heart rate and thereby improve some types of motor performance. In this study, we investigated the effects of different types of music during dart-throw training on both heart rate and dart-throwing performance in 45 ( M age = 19.7, SD = 0.31 years) novice dart throwers who were randomly assigned to either a Slow Music Group (SMG), a Fast Music Group (FMG), or a Control Group (CG). All participants completed three dart-throwing blocks - Pre-Test, Practice, and Post-Test. During the Practice block, participants practiced dart-throwing with either slow-paced, fast-paced or no music according to their assigned group. We recorded the participants’ heart rates and total dart-throwing accuracy scores during Pre-Test and Post-Test. Music-assisted dart-throw training with slow-paced music was effective in significantly inhibiting a performance-related increase in heart rate and was associated with the greatest dart throwing improvement after training.

Cardiovascular changes in the exercising emu

1983 ◽  
Vol 104 (1) ◽  
pp. 193-201 ◽  
Author(s):  
B. Grubb ◽  
D. D. Jorgensen ◽  
M. Conner
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Oxygen Consumption ◽  
Stroke Volume ◽  
Oxygen Content ◽  
Body Mass ◽  
Fold Increase ◽  
Exercise Heart Rate ◽  
Rate Of Oxygen Consumption ◽  
Cardiovascular Variables

Cardiovascular variables were studied as a function of oxygen consumption in the emu, a large, flightless ratite bird well suited to treadmill exercise. At the highest level of exercise, the birds' rate of oxygen consumption (VO2) was approximately 11.4 times the resting level (4.2 ml kg-1 min-1). Cardiac output was linearly related to VO2, increasing 9.5 ml for each 1 ml increase in oxygen consumption. The increase in cardiac output is similar to that in other birds, but appears to be larger than in mammals. The venous oxygen content dropped during exercise, thus increasing the arteriovenous oxygen content difference. At the highest levels of exercise, heart rate showed a 3.9-fold increase over the resting rate (45.8 beats min-1). The mean resting specific stroke volume was 1.5 ml per kg body mass, which is larger than shown by most mammals. However, birds have larger hearts relative to body mass than do mammals, and stroke volume expressed per gram of heart (0.18 ml g-1) is similar to that for mammals. Stroke volume showed a 1.8-fold increase as a result of exercise in the emus, but a change in heart rate plays a greater role in increasing cardiac output during exercise.

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