Cardiovascular adjustments during locomotion in penguins

2005 ◽  
Vol 83 (3) ◽  
pp. 445-454 ◽  
Author(s):  
Jonathan Green ◽  
Anthony Woakes ◽  
Ian Boyd ◽  
Patrick Butler
Keyword(s):  
Heart Rate ◽  
Heart Beat ◽  
Similar Species ◽  
Terrestrial Locomotion ◽  
Oxygen Pulse ◽  
Significant Difference ◽  
Eudyptes Chrysolophus ◽  
Rate Of Oxygen Consumption ◽  
Physical Forces ◽  
The Relationship

The high costs of airborne flapping flight are reflected in a difference between the oxygen pulse (OP; amount of oxygen consumed per heart beat) during flight and that during terrestrial locomotion, as well as a difference in the relationship between heart rate (fH) and rate of oxygen consumption ([Formula: see text]O2). We tested and failed to accept the hypothesis that there would be similar differences in the fH–[Formula: see text]O2 and [Formula: see text]O2–OP relationships during swimming under water and during walking for macaroni penguins (Eudyptes chrysolophus (Brandt, 1837)). We suggest that this may be a result of the penguins having to overcome physical forces different from those experienced by volant birds and possibly a response to limited access to oxygen while porpoising or diving. This result has important implications for those who wish to use fH to estimate [Formula: see text]O2 and hence metabolic rate in the field for this and similar species. To test the utility of the relationship, we compared our results with data obtained previously for this species, and we simultaneously measured [Formula: see text]O2 in a respirometer and estimated [Formula: see text]O2 from fH for 48 h. There was no significant difference in the fH–[Formula: see text]O2 or [Formula: see text]O2–OP relationships between the two studies or between [Formula: see text]O2 estimated from fH and that measured using respirometry.

Heart rate as an indicator of oxygen consumption: influence of body condition in the king penguin

2001 ◽  
Vol 204 (12) ◽  
pp. 2133-2144 ◽  
Author(s):  
G. Froget ◽  
P. J. Butler ◽  
Y. Handrich ◽  
A. J. Woakes
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Body Condition ◽  
Active Oxygen ◽  
The Body ◽  
Regression Equations ◽  
Oxygen Pulse ◽  
Rate Of Oxygen Consumption ◽  
The Impact ◽  
The Relationship

SUMMARY The use of heart rate to estimate field metabolic rate has become a more widely used technique. However, this method also has some limitations, among which is the possible impact that several variables such as sex, body condition (i.e. body fat stores) and/or inactivity might have on the relationship between heart rate and rate of oxygen consumption. In the present study, we investigate the extent to which body condition can affect the use of heart rate as an indicator of the rate of oxygen consumption. Twenty-two breeding king penguins (Aptenodytes patagonicus) were exercised on a variable-speed treadmill. These birds were allocated to four groups according to their sex and whether or not they had been fasting. Linear regression equations were used to describe the relationship between heart rate and the rate of oxygen consumption for each group. There were significant differences between the regression equations for the four groups. Good relationships were obtained between resting and active oxygen pulses and an index of the body condition of the birds. Validation experiments on six courting king penguins showed that the use of a combination of resting oxygen pulse and active oxygen pulse gave the best estimate of the rate of oxygen consumption V̇O2. The mean percentage error between predicted and measured V̇O2 was only +0.81% for the six birds. We conclude that heart rate can be used to estimate rate of oxygen consumption in free-ranging king penguins even over a small time scale (30min). However, (i) the type of activity of the bird must be known and (ii) the body condition of the bird must be accurately determined. More investigations on the impact of fasting and/or inactivity on this relationship are required to refine these estimates further.

The heart rate/oxygen consumption relationship during cold exposure of the king penguin: a comparison with that during exercise

2002 ◽  
Vol 205 (16) ◽  
pp. 2511-2517 ◽  
Author(s):  
G. Froget ◽  
Y. Handrich ◽  
Y. Le Maho ◽  
J.-L. Rouanet ◽  
A. J. Woakes ◽  
...  
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Critical Temperature ◽  
Body Condition ◽  
Heart Beat ◽  
Lower Critical Temperature ◽  
Rate Of Oxygen Consumption ◽  
Free Ranging ◽  
The Relationship ◽  
Environmental Temperatures

SUMMARY This study investigated whether exposure to low ambient temperature could be used as an alternative to exercise for calibrating heart rate (fH)against rate of oxygen consumption(V̇O2) for subsequent use of fH to estimate V̇O2 in free-ranging animals. Using the relationship between the oxygen pulse (OP, the amount of oxygen used per heart beat) and an index of body condition (or nutritional index, NI), a relationship between fH and V̇O2 was established for resting king penguins exposed to a variety of environmental temperatures. Although there was a small but significant increase in the OP above and below the lower critical temperature (-4.9°C), there was no difference in the relationship obtained between the OP and body condition (NI)obtained above or below the lower critical temperature. These results were then compared with those obtained in a previous study in which the relationship between fH and V̇O2 had been established for king penguins during steady-state exercise. The relationship between OP and NI in the present study was not significantly different from the relationship between resting OP and NI in the previous study. However, the relationship was different from that between active OP and NI. We conclude that, at least for king penguins, although thermoregulation does not affect the relationship between resting OP and NI, temperature cannot be used as an alternative to exercise for calibrating fH against V̇O2 for subsequent use of fH to estimate V̇O2 in free-ranging animals.

Heart rate and rate of oxygen consumption of exercising macaroni penguins

2001 ◽  
Vol 204 (4) ◽  
pp. 673-684 ◽  
Author(s):  
J.A. Green ◽  
P.J. Butler ◽  
A.J. Woakes ◽  
I.L. Boyd ◽  
R.L. Holder
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Average Error ◽  
Specific Rate ◽  
Variable Speed ◽  
Treadmill Speed ◽  
Eudyptes Chrysolophus ◽  
Rate Of Oxygen Consumption ◽  
Free Ranging ◽  
The Relationship

Twenty-four macaroni penguins (Eudyptes chrysolophus) from three groups, breeding males (N=9), breeding females (N=9) and moulting females (N=6), were exercised on a variable-speed treadmill. Heart rate (fH) and mass-specific rate of oxygen consumption (sVO2) were recorded from the animals, and both fh and sVO2 were found to increase linearly with increasing treadmill speed. A linear regression equation described the relationship between fh and sVO2 for each individual. There were no significant differences in these regressions between breeding and moulting females. There were significant differences in these relationships between all females and breeding males. fH and s VO2 were recorded from five of these animals for a total of 24 h. When fh was used to predict sVO2 for the 24 h period using the derived regressions, the estimate was not significantly different from the measured values, with an average error of −2.1 %. When fh was used to predict sVO2 for the 5 min intervals used for the calibration in all 24 birds, the estimate was not significantly different from the observed values, and the average error was only +0.47 %. Since the fH/sVO2 relationship was the same during periods of the annual cycle when the animals were inactive/fasting and active/foraging, it seems reasonable that, as long as sex differences are taken into account, fh can be used to predict the metabolic rates of free-ranging macaroni penguins all year round.

Oxygen pulse in guinea pigs in hyperbaric helium and hydrogen

1997 ◽  
Vol 82 (3) ◽  
pp. 988-997 ◽  
Author(s):  
Susan R. Kayar ◽  
Erich C. Parker
Keyword(s):  
Heart Rate ◽  
Core Temperature ◽  
Guinea Pigs ◽  
Multivariate Regression Analysis ◽  
Heart Beat ◽  
Hyperbaric Chamber ◽  
Oxygen Pulse ◽  
Chamber Temperature ◽  
Hyperbaric Environment ◽  
Temperature And Pressure

Kayar, Susan R., and Erich C. Parker. Oxygen pulse in guinea pigs in hyperbaric helium and hydrogen. J. Appl. Physiol. 82(3): 988–997, 1997.—We analyzed O2 pulse, the total volume of O2 consumed per heart beat, in guinea pigs at pressures from 10 to 60 atmospheres. Animals were placed in a hyperbaric chamber and breathed 2% O2 in either helium (heliox) or hydrogen (hydrox). Oxygen consumption rate (V˙o 2) was measured by gas chromatographic analysis. Core temperature and heart rate were measured by using surgically implanted radiotelemeters. TheV˙o 2 was modulated over a fourfold range by varying chamber temperature from 25 to 36°C. There was a direct correlation betweenV˙o 2 and heart rate, which was significantly different for animals in heliox vs. hydrox ( P = 0.003). By using multivariate regression analysis, we identified variables that were significant to O2 pulse: body surface area, chamber temperature, core temperature, and pressure. After normalizing for all nonpressure variables, the residual O2 pulse was found to decrease significantly ( P = 0.02) with pressure for animals in heliox but did not decrease significantly ( P = 0.38) with pressure for animals in hydrox over the range of pressures studied. This amounted to a roughly 25% lower O2 pulse for normothermic animals in 60 atmospheres heliox vs. hydrox. These results suggest that reduction of cardiovascular efficiency in a hyperbaric environment can be mitigated by the choice of breathing gas.

The Relationship between Heart Rate Deflection and Ventilatory Threshold in Children Following Heart Surgery

1995 ◽  
Vol 7 (3) ◽  
pp. 263-269 ◽  
Author(s):  
Ralph K.L. Rogers ◽  
Tony Reybrouck ◽  
Maria Weymans ◽  
Monique Dumoulin ◽  
Marc Gewillig ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Surgery ◽  
Surgical Repair ◽  
Ventilatory Threshold ◽  
Linear Regression Analysis ◽  
Accurate Predictor ◽  
Graded Exercise Test ◽  
Significant Difference ◽  
Graded Exercise ◽  
The Relationship

This study assessed the relationship between the VO2 measured at ventilatory threshold (VT) and the VO2 measured at the point of deflection from linearity of heart rate (HRD). Twelve children (10 boys and 2 girls) with a mean age of 11.3 years (±4.8) performed a graded exercise test to determine VT and HRD. All children had undergone surgical repair for d-transposition of the great arteries at approximately 13 months of age. Because of failure to demonstrate HRD, the data from 4 patients were excluded from statistical analysis. For the remaining 8 patients there was no significant difference between mean VO2 (ml/kg/min) at VT and HRD (26.6 ± 6.4 vs. 26.3 ± 6.8; p > 0.25). Linear regression analysis revealed a correlation of r = 0.92 between the VO2 measured at VT and the VO2 measured at HRD. Only 8 of the 12 patients (66%) in this study satisfied criteria needed to identify the HRD. Therefore HRD may be an accurate predictor of VT in most but not all children who have had surgery for d-transposition of the great arteries.

scholarly journals Evaluación del Talk Test como método para estimar la intensidad del ejercicio en niños sanos (Evaluation of the Talk Test as a method to estimate exercise intensity in healthy children)

Retos ◽  
2019 ◽  
pp. 303-308
Author(s):  
Danissa Hernández ◽  
Natalia Pacheco ◽  
Issis Poblete ◽  
Héctor Tórres ◽  
Iván Rodríguez-Núnez
Keyword(s):  
Heart Rate ◽  
Exercise Intensity ◽  
Healthy Children ◽  
Exercise Tests ◽  
Indirect Methods ◽  
A Value ◽  
Significant Difference ◽  
Intensity Of Exercise ◽  
Incremental Step ◽  
The Relationship

Introducción: La frecuencia cardíaca (FC) ha sido tradicionalmente utilizada para regular la intensidad del ejercicio, sin embargo, presenta limitaciones para su cuantificación sin un monitor cardiaco. En consecuencia, métodos indirectos, como el Talk Test (TT), han sido validados en adultos, no así en población infantil. El objetivo de este estudio fue determinar la relación entre el TT y los métodos objetivos para cuantificar la intensidad del ejercicio en niños sanos chilenos. Métodos: Se consideró a niños sanos de ambos géneros entre 8 y 12 años. Los sujetos realizaron dos pruebas de ejercicio incremental en escalón separadas por 7 días. El TT se incorporó en una de las dos pruebas aleatoriamente. Se midió la FC, percepción del esfuerzo (PE) y carga de trabajo, cada un minuto durante la prueba. Se comparó la FC, PE y carga de trabajo entre la respuesta positiva (TT+/+), equívoca (TT+/-) y negativa (TT-/-) del TT. Adicionalmente, se determinó la confiabilidad de los parámetros cardiorrespiratorios durante el TT. Un valor de p<.05 se consideró significativo. Resultados: Ingresaron 48 sujetos, edad 9.7±1.1 años. Existió diferencia significativa en los parámetros cardiorrespiratorios entre las respuestas del TT (p<.0001). El % de la FC máxima en TT+/+ fue 72.2 ± 8.2, en TT+/- fue 87.9 ± 8.1 y en TT-/- fue 92.0 ± 7.5%. La confiabilidad de los parámetros cardiorrespiratorios durante el TT fue regular a excelente en ambos géneros. Conclusiones: El TT se relacionó con los parámetros cardiorrespiratorios para regular la intensidad del ejercicio en niños sanos.Abstract. Introduction: Heart rate (HR) has traditionally been used to regulate the intensity of exercise; however, its measurement is limited in the absence of a heart rate device. Consequently, indirect methods, such as the Talk Test (TT), have been validated in adults, yet not in children. The objective of this study was to determine the relationship between TT and objective methods to quantify the intensity of exercise in healthy Chilean children. Methods: Healthy children of both genders aged between 8 and 12 years old were considered for the study. The participants performed two incremental step exercise tests separated by 7 days. The TT was incorporated in one of the two tests randomly. The HR, effort perception (EP) and workload were measured every one minute during the test. HR, EP and workload were compared by positive (TT + / +), equivocal (TT +/-), and negative (TT - / -) response of the TT. Additionally, the reliability of cardiorespiratory parameters during TT was determined. A value of p <0.05 was considered significant. Results: 48 participants aged 9.7 ± 1.1 years old were selected. There was a significant difference in cardiorespiratory parameters between the TT responses (p <.001). The percent of maximum HR in TT + / + was 72.2 ± 8.2%, in TT +/- was 87.9 ± 8.1% and in TT - / - was 92.0 ± 7.5%. The reliability of cardiorespiratory parameters during TT was fair to excellent in both genders. Conclusions: TT was associated to cardiorespiratory parameters to regulate exercise intensity in healthy children.

scholarly journals Autonomic Correlates of the Sedation Threshold

1973 ◽  
Vol 18 (3) ◽  
pp. 239-246
Author(s):  
B. K. Tan
Keyword(s):  
Heart Rate ◽  
Individual Differences ◽  
Experimental Design ◽  
Direct Action ◽  
Chronic Schizophrenia ◽  
Autonomic Activity ◽  
Significant Difference ◽  
Anxiolytic Drugs ◽  
The Relationship ◽  
Depressive Patients

This study is concerned with the relationship between sedation threshold and autonomic measures in two groups — depressive patients and those suffering from chronic schizophrenia. The sedation threshold was determined according to Shagass' method. In addition, autonomic activity (heart rate, palmar conductance and respiration rate) was simultaneously recorded. There was no evidence of a significant relationship between sedation threshold and autonomic measures. No significant difference in autonomic activity was found between the two groups. Individual differences were shown by each subject having his own idiosyncratic pattern of autonomic activity, regardless of the diagnosis. Consistency of this pattern was found in a substantial proportion of each group. The overall autonomic effect of sodium amytal was insignificant. In particular, the three autonomic measures failed to differentiate between the conditions of rest and sedation, and it was concluded that the sedative influence of sodium amytal is not exerted through a direct action on the autonomic centres. It was suggested that the experimental design would be suitable for comparing the action of sedative and anxiolytic drugs.

P4425The exercise-induced troponin I elevation is highly correlated with power output during exercise in recreational cyclists with coronary atherosclerosis

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
M Bjorkavoll-Bergseth ◽  
O Kleiven ◽  
K M Aakre ◽  
T Wiktorski ◽  
C Erevik ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Coronary Atherosclerosis ◽  
Troponin I ◽  
Average Power ◽  
Strenuous Exercise ◽  
Significant Difference ◽  
Highly Correlated ◽  
Exercise Induced ◽  
The Relationship

Abstract Background Following strenuous exercise there is an increase cardiac Troponins (cTn) elevation considered being a physiological response. During prolonged strenuous physical activity, high work-loads may induce demand myocardial ischemia due to an oxygen demand/supply mismatch in susceptible subjects, causing an excessive cTn elevation. Purpose This study aimed to assess the relationship between exercise-induced cTnI elevation and direct measurement of work performed during prolonged strenuous exercise in subjects with and without atherosclerotic CAD. Methods Work during a 91 km mountain bike race was quantified by Stages™ power meters. Power (Watt) and heart rate data were stored in Garmin™ Forerunner 935 monitors. Coronary computed tomography angiography was performed after the race. Blood pressure was measured 4 times during the race. Blood samples (hs-cTnI from Abbot Diagnostics) were obtained one day prior to the race and at 3 and 24 h after the race. Data are presented as mean±SD or median (25th and 75th percentile). Results 40 subjects (10 women) were included in the final analysis. 15 Participants (4 women) had atherosclerosis, none had obstructive CAD. These participants were significantly older (55±8 years vs. 46±8 years p=0.007) and had higher training volumes (METS: 69 (64–102) hrs/week) compared with normal subjects (METS: 51 (33–88) hrs/week) (p=0.03). Baseline cTnI was higher (p=0.04) in the atherosclerotic group (4.5 (3.4–8.8) ng/L) compared with normals (2.6 (1.6–4.8) ng/L). There were no differences in baseline blood pressure, peak VO2 max, heart rate or BMI. There was no significant difference in race duration between normals (3.9 (3.5–4.5) hrs) and subjects with atherosclerosis (4.1 (3.6–4.5) hrs). During the race there were no differences in peak power or peak Watt/kg. cTnI increased after the race in all participants, but there were no differences between groups: 3h: atherosclerosis: 89 (27–131) ng/L vs. normal 77 (36–104) ng/L, 24h: atherosclerosis: 13 (6.3–23.7) ng/L vs. normal: 17 (12–37) ng/L. There were no significant difference between the groups in average power during the race: atherosclerosis: 167±50 Watt vs. 174 (±50) Watt or ratio: 2.0±0.49 Watt/kg vs 2.2±0.58 Watt/kg during the race. Maximal systolic and diastolic blood pressures during the race were higher (p=0.002) in the atherosclerotic group: SBP: 241±14 mmHg vs. 219±26 mmHg, DBP: 107±8 vs 95±8 mmHg. In atherosclerotic subjects cTnI both at 3h and 24 h were highly correlated (p<0.001) with Watt/kg ratio during the race in contrast to no correlations in the normal group (Figure). Conclusions Our findings suggest that the presence of coronary atherosclerosis, even in the absences of significant stenosis, alters the relationship between workload and the troponin response. This indicates different release kinetics in exercise-induced cTn in participants with and without CAD, with prolonged elevation in cTnI in CAD subjects exceeding the highest work-intensities. Acknowledgement/Funding Grant Western Norway Health service, Grant ConocoPhillips, Grant Simon Fougner Hartmanns Familyfund

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