The metabolic cost of flight in unrestrained birds

1978 ◽  
Vol 75 (1) ◽  
pp. 223-229 ◽  
Author(s):  
J. R. Torre-Bueno ◽  
J. Larochelle
Keyword(s):  
Carbon Dioxide ◽  
Metabolic Rate ◽  
Metabolic Cost ◽  
Large Change ◽  
Carbon Dioxide Production ◽  
The Body ◽  
Wingbeat Frequency ◽  
Bird Flight ◽  
Body Attitude ◽  
High Speeds

Oxygen consumption and carbon dioxide production were measured during flight in unrestrained starlings by a new method. Mean RQ after the first 30 min of flight was 0.69 +/− 0.08 (+/− S.D.). Mean rate of carbon dioxide production was 19.7 +/− 2.2 ml CO2/min, which corresponds to a metabolic rate of 8.9 +/− 1 W. Metabolic rate during flight did not change significantly over a range of air speeds from 8 to 18 m/s and birds would not fly at speeds outside of this range. Current theories of bird flight predict a large change in metabolic rate over the same range of speeds. Wingbeat frequency was constant at 12 +/− 0.5 Hz. Wingbeat amplitude reached a minimum at a speed of 14 m/s and increased at both higher and lower speeds. Angle between the body and horizontal was least at high speeds and increased at low speeds. As existing theories do not take into account the change of drag resulting from changes in body attitude, this may be a cause of the discrepancies between theory and observation.

Metabolism during normoxia, hyperoxia, and recovery in newborn rats

1992 ◽  
Vol 70 (3) ◽  
pp. 408-411 ◽  
Author(s):  
Peter B. Frappell ◽  
Andrea Dotta ◽  
Jacopo P. Mortola
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Metabolic Rate ◽  
Carbon Dioxide Production ◽  
Oxygen Availability ◽  
Aerobic Metabolism ◽  
Newborn Rats ◽  
Ambient Temperatures ◽  
Positive Effects

Aerobic metabolism (oxygen consumption, [Formula: see text], and carbon dioxide production, [Formula: see text]) has been measured in newborn rats at 2 days of age during normoxia, 30 min of hyperoxia (100% O2) and an additional 30 min of recovery in normoxia at ambient temperatures of 35 °C (thermoneutrality) or 30 °C. In normoxia, at 30 °C [Formula: see text] was higher than at 35 °C. With hyperoxia, [Formula: see text] increased in all cases, but more so at 30 °C (+20%) than at 35 °C (+9%). Upon return to normoxia, metabolism readily returned to the prehyperoxic value. The results support the concept that the normoxic metabolic rate of the newborn can be limited by the availability of oxygen. At temperatures below thermoneutrality the higher metabolic needs aggravate the limitation in oxygen availability, and the positive effects of hyperoxia on [Formula: see text] are therefore more apparent.Key words: neonatal respiration, oxygen consumption, thermoregulation.

The Physiology and Energetics of Bat Flight

1972 ◽  
Vol 57 (2) ◽  
pp. 317-335 ◽  
Author(s):  
STEVEN P. THOMAS ◽  
RODERICK A. SUTHERS
Keyword(s):  
Metabolic Rate ◽  
Metabolic Cost ◽  
Minute Volume ◽  
High Metabolic Rate ◽  
Abrupt Increase ◽  
Bird Flight ◽  
Terrestrial Mammals ◽  
Oxygen Capacity ◽  
Physiological Adaptations ◽  
Phyllostomus Hastatus

1. The energetics and physiological responses to flight of the echolocating bat Phyllostomus hastatus were studied to determine the energy requirements and physiological adaptations for mammalian flight. 2. The metabolic cost of bat flight is approximately comparable to that of bird flight and requires a metabolic rate appreciably greater than has been reported for terrestrial mammals during exercise. During flight P. hastatus consumed between 24.7 and 29.1 ml O2 (g h)-1, which is about four times its metabolic rate immediately prior to flight and more than 30 times its oxygen consumption while resting with a TR of 36.5 °C in a small chamber. 3. The onset of flight is accompanied by an abrupt increase in both the heart rate, from about 8.7 to 13 beats/sec, and the respiratory rate, from 3 to about 9.6/sec. Rectal temperature is elevated during flight and maintained at about 41.8 °C. The respiratory quotient, which averages 0.83 in a quietly resting bat, rises to a little over 1.0 during the first few minutes of flight. 4. The minimum estimated tidal volume during flight is about 1.4 ml. One respiratory cycle occurs with each wingbeat, corresponding to an estimated minute volume of 840 ml, which is comparable to that reported for the flying budgerigar. The amount of oxygen extracted by P. hastatus from a given volume of tidal air is also comparable to the efficiency of ventilation reported for this bird. 5. High hematocrit values of about 60%, and a high oxygen capacity of 27.5 vol % of P. hastatus blood, must represent important adaptations for enabling the flying bat to maintain such a high metabolic rate.

scholarly journals The fasting metabolism of cattle

1966 ◽  
Vol 20 (1) ◽  
pp. 103-111 ◽  
Author(s):  
K. L. Blaxter ◽  
F. W. Wainman
Keyword(s):  
Carbon Dioxide ◽  
Body Weight ◽  
Oxygen Consumption ◽  
Coefficient Of Variation ◽  
Methane Production ◽  
Carbon Dioxide Production ◽  
The Body ◽  
Nitrogen Excretion ◽  
Urinary Nitrogen Excretion ◽  
Urinary Nitrogen

1. The metabolism of seventeen steers was determined on forty-nine occasions during fasts of either 112 or 136 h duration.2. Faeces continued to be produced during fasts of up to 136 h duration at rates which were 15–20% of those noted before the fasts began.3. Carbon dioxide production and oxygen consumption fell continuously throughout with animals weighing less than 200 kg but changed little after 88 h in animals weighing more than 200 kg. Methane production was considerably reduced during fasting but did not disappear. Urinary nitrogen excretion changed very little. Of the total loss of energy from the body, the loss of protein accounted for 25%. This was unaffected by age or size of animal.4. With individual Ayrshire steers, metabolism increased during growth with body-weight raised to the power 0.68±0.05. No greater precision of estimate was obtained from logarithmic regressions of metabolism on body-weight than from linear ones.5. Seven Ayrshire steers had a mean fasting metabolism of 100±1.6 kcal/kg W0.73 24 h, eight Black cattle of the Aberdeen Angus type a fasting metabolism of 81±1.5 kcal/kg W0.73 24 h and two Ayrshire x Beef Shorthorn steers a fasting metabolism of 96±2.9 kcal/kg W0.73 24 h. Variation in the fasting metabolism of an individual steer from time to time, expressed as a coefficient of variation, was ±7.4%.6. The results are discussed in relation to interspecies generalizations about the relation between fasting metabolism and body-weight.

scholarly journals Calculating metabolic energy expenditure across a wide range of exercise intensities: the equation matters

2018 ◽  
Vol 43 (6) ◽  
pp. 639-642 ◽  
Author(s):  
Shalaya Kipp ◽  
William C. Byrnes ◽  
Rodger Kram
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Energy Expenditure ◽  
Metabolic Rate ◽  
Carbon Dioxide Production ◽  
Metabolic Energy ◽  
Distance Runners ◽  
Wide Range ◽  
Using Data ◽  
Metabolic Energy Expenditure

We compared 10 published equations for calculating energy expenditure from oxygen consumption and carbon dioxide production using data for 10 high-caliber male distance runners over a wide range of running velocities. We found up to a 5.2% difference in calculated metabolic rate between 2 widely used equations. We urge our fellow researchers abandon out-of-date equations with published acknowledgments of errors or inappropriate biochemical/physical assumptions.

scholarly journals Flight kinematics of the barn swallow (Hirundo rustica) over a wide range of speeds in a wind tunnel

2001 ◽  
Vol 204 (15) ◽  
pp. 2741-2750 ◽  
Author(s):  
Kirsty J. Park ◽  
Mikael Rosén ◽  
Anders Hedenström
Keyword(s):  
Wind Tunnel ◽  
Tilt Angle ◽  
Angle Of Attack ◽  
The Body ◽  
Hirundo Rustica ◽  
Body Tilt ◽  
High Plasticity ◽  
Wingbeat Frequency ◽  
High Speeds ◽  
Wide Range

SUMMARYTwo barn swallows (Hirundo rustica) flying in the Lund wind tunnel were filmed using synchronised high-speed cameras to obtain posterior, ventral and lateral views of the birds in horizontal flapping flight. We investigated wingbeat kinematics, body tilt angle, tail spread and angle of attack at speeds of 4–14ms−1. Wingbeat frequency showed a clear U-shaped relationship with air speed with minima at 8.9ms−1(bird 1) and 8.7ms−1 (bird 2). A method previously used by other authors of estimating the body drag coefficient (CD,par) by obtaining agreement between the calculated minimum power (Vmin) and the observed minimum wingbeat frequency does not appear to be valid in this species, possibly due to upstroke pauses that occur at intermediate and high speeds, causing the apparent wingbeat frequency to be lower. These upstroke pauses represent flap-gliding, which is possibly a way of adjusting the force generated to the requirements at medium and high speeds, similar to the flap-bound mode of flight in other species. Body tilt angle, tail spread and angle of attack all increase with decreasing speed, thereby providing an additional lift surface and suggesting an important aerodynamic function for the tail at low speeds in forward flight. Results from this study indicate the high plasticity in the wingbeat kinematics and use of the tail that birds have available to them in order to adjust the lift and power output required for flight.

Limits of human lung function at high altitude

2001 ◽  
Vol 204 (18) ◽  
pp. 3121-3127
Author(s):  
Robert B. Schoene
Keyword(s):  
Carbon Dioxide ◽  
High Altitude ◽  
Respiratory Muscles ◽  
Metabolic Cost ◽  
Carbon Dioxide Flux ◽  
Vital Role ◽  
The Body ◽  
Hypoxic Environment ◽  
Capillary Membrane ◽  
Alveolar Capillary

SUMMARY This paper will review the function of the lung at high altitude in humans. As the first interface between the environment and the body, the lung serves a vital role in the transfer of oxygen from the air to the blood. I will describe the limits of response and adaptation of the lung to this hypoxic stress, both at rest and during exercise when oxygen and carbon dioxide flux from the tissues is greater. First, ventilation will be described in terms of the hypoxic stimulus that causes an increase in breathing (ventilatory drives) and the metabolic cost from the respiratory muscles incurred by this increase. Individuals at high altitude also have a substantial sense of dyspnea which, in and of itself, may limit exercise tolerance. The final function of the lung is to exchange oxygen and carbon dioxide, which it does at the alveolar–capillary interface. Here, important limitations are encountered because the driving pressure for oxygen from the air to the blood is lower and the more rapid transit time of blood across the pulmonary capillary allows less time for equilibration of oxygen with the blood. Both these phenomena lead to a limitation of diffusion of oxygen across the alveolar–capillary membrane and, thus, more accentuated hypoxemia. In spite of these restrictions, humans still do remarkably well in times of great stress from the hypoxic environment.

Role of Panchakarma in the management of Hypothyroidism

2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Dr.Suraj Kumbar ◽  
Dr.Lohith BA ◽  
Dr.Ashvinikumar M ◽  
Dr. Amritha R ◽  
Dr. Shameem Banu
Keyword(s):  
Metabolic Rate ◽  
Pituitary Gland ◽  
Life Style ◽  
The Body ◽  
Management Guidelines ◽  
Quality Of Food ◽  
Sedentary Life ◽  
Sedentary Life Style

We are in technical era where there is more of sedentary life style and stress along with this urbanization is affecting our quality of food and health. This is leading to many lifestyle disorders and hormonal imbalances in our body. Hypothyroidism one among the endocrinal disorder. Thyroid is an endocrinal gland secrets T3 and T4 hormones regulated by TSH which is secreted by Pituitary gland. These hormones have two major effects on the body, 1) To increase the overall metabolic rate in the body 2) To stimulate growth in children. Hypothyroidism is common health issue in India. The highest prevalence of hypothyroidism (13.1%) is noted in people aged 46-54yrs old. With people aged 18-35 yrs being less affected (7.5%). To prevent these hazards Panchakarma is beneficiary to maintain metabolic rate. Here an attempt is made to diagnose hypothyroidism in the light of Ayurveda and management guidelines through Panchakarma.

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