Effect of ambient temperature on heat production and heat loss in burn patients

1975 ◽  
Vol 38 (4) ◽  
pp. 593-597 ◽  
Author(s):  
D. W. Wilmore ◽  
A. D. Mason ◽  
D. W. Johnson ◽  
B. A. Pruitt
Keyword(s):  
Metabolic Rate ◽  
Ambient Temperature ◽  
Heat Loss ◽  
Environmental Temperature ◽  
Burn Patients ◽  
Evaporative Water ◽  
Ambient Temperatures ◽  
Wet Heat ◽  
Total Body ◽  
Normal Men

Four controls and eight burned patients with thermal injury ranging from 7 to 84% total body surface were studied in an environmental chamber at 25 and 33 degrees C ambient temperature and a constant vapor pressure during two consecutive 24-h periods. Hypermetabolism was present in the burn patients in both ambient temperatures and core and skin temperatures were consistently higher than in the normal men despite increased evaporative water loss. The higher environmental temperature decreased metabolic rate in patients with large thermal injuries in whom the decrement in dry heat loss produced by higher ambient temperature exceeded the increase of wet heat loss. In patients with burns smaller than 60%, these changes equaled one another and higher environmental temperature exerted no effect on metabolic rate. Core-skin heat conductivity increased with burn size; patients with large burns were characterized by inadequate core-skin insulation when exposed to the cooler environment, necessitating the compensatory increase of metabolic rate. This increase, however, was small and of the order of 5–8 kcal times m-2 times h-1.

Thermoregulation of African and European Honeybees during Foraging, Attack, and Hive Exits and Returns

1979 ◽  
Vol 80 (1) ◽  
pp. 217-229 ◽  
Author(s):  
HEINRICH BERND
Keyword(s):  
Metabolic Rate ◽  
Ambient Temperature ◽  
Heat Loss ◽  
Warm Up ◽  
Ambient Temperatures ◽  
Thoracic Temperature

1. While foraging, attacking, or leaving or returning to their hives, both the African and European honeybees maintained their thoracic temperature at 30 °C or above, independent of ambient temperature from 7 to 23 °C (in shade). 2. Thoracic temperatures were not significantly different between African and European bees. 3. Thoracic temperatures were significantly different during different activities. Average thoracic temperatures (at ambient temperatures of 8–23 °C) were lowest (30 °C) in bees turning to the hive. They were 31–32 °C during foraging, and 36–38 °C in bees leaving the hive, and in those attacking. The bees thus warm up above their temperature in the hive (32 °C) before leaving the colony. 4. In the laboratory the bees (European) did not maintain the minimum thoracic temperature for continuous flight (27 °C) at 10 °C. When forced to remain in continuous flight for at least 2 min, thoracic temperature averaged 15 °C above ambient temperature from 15 to 25 °C, and was regulated only at high ambient temperatures (30–40 °C). 5. At ambient temperatures > 25 °C, the bees heated up during return to the hive, attack and foraging above the thoracic temperatures they regulated at low ambient temperatures to near the temperatures they regulated during continuous flight. 6. In both African and European bees, attack behaviour and high thoracic temperature are correlated. 7. The data suggest that the bees regulate thoracic temperature by both behavioural and physiological means. It can be inferred that the African bees have a higher metabolic rate than the European, but their smaller size, which facilitates more rapid heat loss, results in similar thoracic temperatures.

Thermoregulatory, metabolic and ventilatory physiology of the western barred bandicoot (Perameles bougainville bougainville) in summer and winter

2006 ◽  
Vol 54 (1) ◽  
pp. 15 ◽  
Author(s):  
Alexander N. Larcombe ◽  
Philip C. Withers
Keyword(s):  
Body Temperature ◽  
Metabolic Rate ◽  
Ambient Temperature ◽  
Thermal Conductance ◽  
Carbon Dioxide Production ◽  
Minute Volume ◽  
Evaporative Water ◽  
Ambient Temperatures ◽  
Time Of Year ◽  
High Basal Metabolic Rate

The metabolic, thermoregulatory and ventilatory physiology of western barred bandicoots (Perameles bougainville bougainville), measured in the laboratory during summer and winter at ambient temperatures of 10 and 30°C, is relatively unusual for a peramelid marsupial. It has a low thermoneutral body temperature (33.7 ± 0.2°C), a very high basal metabolic rate (0.68 ± 0.03 mL O2 g–1 h–1 at ambient temperature = 30°C), low respiratory exchange ratios (often less than 0.7) and a high thermal conductance, reflecting its high oxygen consumption rate and low body temperature. Ventilatory frequency and tidal volume were variable between seasons, although minute volume and oxygen extraction efficiency were not. Minute volume of the western barred bandicoot was higher than expected, reflecting its high metabolic rate. Time of year (i.e. season) had an effect on some aspects of metabolic, thermoregulatory and ventilatory physiology (carbon dioxide production, respiratory exchange ratio, total evaporative water loss), but this effect was not as substantial nor as general as the effect of ambient temperature.

Development of thermoregulation in ducklings

1972 ◽  
Vol 50 (10) ◽  
pp. 1243-1250 ◽  
Author(s):  
G. Untergasser ◽  
J. S. Hayward
Keyword(s):  
Metabolic Rate ◽  
Heat Loss ◽  
Cold Resistance ◽  
Rapid Development ◽  
Metabolic Rates ◽  
Ambient Temperatures ◽  
Common Eiders

The embryos of mallards and scaups show no evidence of homeothermy before the point of hatching. The ability to thermoregulate develops quickly directly after hatching, so that day-old mallards remain homeothermic for at least 2.5 h at ambient temperatures down to +2 °C. The lowest ambient temperatures at which 1-day-old scaups and common eiders remain homeothermic for at least 2.5 h are −2 °C and −7 °C respectively. This rapid development of cold resistance is related to increases in peak metabolic rates and insulative capacities. In embryos of pipped eggs, metabolic rates do not exceed 1.1 ml O2/g h for mallards and 1.6 ml/g h for scaups, while the peak metabolic rates of the day-old young are 6.1 and 7.0 ml/g h respectively. One-day-old common eiders have a peak metabolic rate of about 5 ml/g h. After an age of 3 days, cold resistance increases with age while peak metabolic rates decrease, indicating that reduced heat loss contributes to increased cold resistance. At an age of 7 days, mallards can maintain homeothermy for at least 2.5 h at −4 °C, scaups at −14 °C, and common eiders at −16 °C. Insulation indices of eider ducklings are significantly higher than those of young mallards and scaups.

scholarly journals Mosaic metabolic ageing: Basal and standard metabolic rate age in opposite directions and independent of environmental quality, sex or lifespan in a passerine

2019 ◽  
Author(s):  
Michael Briga ◽  
Simon Verhulst
Keyword(s):  
Metabolic Rate ◽  
Ambient Temperature ◽  
Environmental Quality ◽  
Basal Metabolic Rate ◽  
Standard Metabolic Rate ◽  
Ageing Process ◽  
List Type ◽  
Ambient Temperatures ◽  
Metabolic Traits ◽  
Ageing Rate

AbstractCrucial to our understanding of the ageing process is identifying how traits change with age, which variables alter their ageing process and whether these traits associate with lifespan.We here investigated metabolic ageing in zebra finches. We longitudinally monitored 407 individuals during six years and collected 3213 measurements of two independent mass-adjusted metabolic traits: basal metabolic rate (BMRm) at thermoneutral temperatures and standard metabolic rate (SMRm), which is the same as BMRm but at ambient temperatures below thermoneutrality.BMRmdecreased linearly with age, consistent with earlier reports. In contrast, SMRmincreased linearly with age. To the best of our knowledge, this is the first quantification of SMRm ageing, and thereby of the contrast between SMRm and BMRm ageing.Neither metabolic rate nor metabolic ageing rate were associated with individual lifespan. Moreover, experimental manipulations of environmental quality that decreased BMRm and SMRm and shortened lifespan with 6 months (12%) did not affect the ageing of either metabolic trait. Females lived 2 months (4%) shorter than males, but none of the metabolic traits showed sex-specific differences at any age.Our finding that ageing patterns of metabolic rate vary depending on the ambient temperature illustrates the importance of studying ageing in an ecologically realistic setting.Our results add to the mounting evidence that within an organism ageing is an asynchronous process.

A mechanism by which helium increases metabolism in small mammals

1960 ◽  
Vol 199 (2) ◽  
pp. 243-245 ◽  
Author(s):  
H. A. Leon ◽  
S. F. Cook
Keyword(s):  
Thermal Conductivity ◽  
Oxygen Consumption ◽  
Ambient Temperature ◽  
Skin Temperature ◽  
Heat Loss ◽  
Small Mammals ◽  
Thermal Gradient ◽  
Oxygen Mixture ◽  
Ambient Temperatures ◽  
Long Evans

The oxygen consumption of male Long-Evans rats was determined at three different ambient temperatures in air and in an equivalent helium-oxygen mixture. It was found that when the ambient temperature is near the skin temperature of the rat, the effect of helium is insignificant. If the ambient temperature is lowered, helium induces an increased metabolism over air at the same temperature. Since helium has a thermal conductivity about six times greater than nitrogen, it is concluded that the accelerated metabolism is in response to the greater heat loss in the presence of helium and the magnitude of this response is proportional to the thermal gradient between the animal and the environment.

Water Metabolism of the Domestic Fowl From Hatching to Maturity

1957 ◽  
Vol 190 (1) ◽  
pp. 139-141 ◽  
Author(s):  
W. Medway ◽  
M. R. Kare
Keyword(s):  
Metabolic Rate ◽  
Basal Metabolic Rate ◽  
Water Loss ◽  
Total Body Water ◽  
Domestic Fowl ◽  
Direct Method ◽  
Body Water ◽  
Water Metabolism ◽  
Evaporative Water ◽  
Total Body

The total evaporative water loss, total body water by the direct method and the basal metabolic rate were determined on domestic fowl at various stages of growth. The trials were conducted on a total of 440 birds. The combined respiratory and cutaneous water loss was high on the 1st day of life, dropped to a minimum between 1 and 2 weeks of age, rose sharply at 2–4 weeks of age, then gradually tapered off to the value observed in the adult. The total body water and the total body water on a fat-free basis was quite high on the 1st day of life, then gradually decreased to that of the adult. The basal metabolic rate was low on the 1st day, rose sharply to a maximum at 2–4 weeks of age and then gradually tapered off to that of the adult.

Effect of ambient temperature on development of prostaglandin E1 hyperthermia in the rhesus monkey

1978 ◽  
Vol 44 (5) ◽  
pp. 751-758 ◽  
Author(s):  
C. C. Barney ◽  
R. S. Elizondo
Keyword(s):  
Rhesus Monkey ◽  
Metabolic Rate ◽  
Rhesus Monkeys ◽  
Prostaglandin E1 ◽  
Co2 Production ◽  
Evaporative Heat Loss ◽  
Water Losses ◽  
Evaporative Water ◽  
Ambient Temperatures ◽  
Skin Temperatures

Prostaglandin E1 (PGE1) hyperthermia (fever) was studied at ambient temperatures (Ta) of 18, 27, and 35 degrees C in four male unanesthetized rhesus monkeys (Macaca mulatta) implanted with four guide tubes and one reentrant tube within the preoptic anterior hypothalamus (PO/AH). Rectal, hypothalamic, and mean weighted skin temperatures, O2 consumption, CO2 production, and respiratory and total evaporative water losses were measured continuously before and during PGE1 fever at each Ta. The febrile reponse to PO/AH PGE1 injection was dose responsive and was less at a Ta of 35 degrees C than at the other Ta's. At a Ta of 18 degrees C, fever was brought about primarily by an increase in metabolic rate. At a Ta of 27 degrees C, fever was produced by an increase in metabolic rate and by skin vasoconstriction. At a Ta of 35 degrees C, fever was the result of an increase in metabolic rate and a decrease in sweating evaporative heat loss. At each Ta some generalized skin vasconstriction also occurred. During the plateau phase of the fever, the measured heat losses and gains returned to near control levels. The data indicate that the rhesus monkey shows specific thermoregulatory responses to PO/AH PGE1 injection and would be a good model for the study of thermoregulation during fever in higher primates.

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