Heat exchanges in wet suits

1985 ◽  
Vol 58 (3) ◽  
pp. 770-777 ◽  
Author(s):  
A. H. Wolff ◽  
S. R. Coleshaw ◽  
C. G. Newstead ◽  
W. R. Keatinge
Keyword(s):  
Body Temperature ◽  
Water Temperature ◽  
Cold Water ◽  
Whole Body ◽  
Metabolic Responses ◽  
Body Temperatures ◽  
Postural Changes ◽  
Wide Range ◽  
Heat Exchanges ◽  
Skin Temperatures

Flow of water under foam neoprene wet suits could halve insulation that the suits provided, even at rest in cold water. On the trunk conductance of this flow was approximately 6.6 at rest and 11.4 W . m-2 . C-1 exercising; on the limbs, it was only 3.4 at rest and 5.8 W . m-2 . degrees C-1 exercising; but during vasoconstriction in the cold, skin temperatures on distal parts of limbs were lower than were those of the trunk, allowing adequate metabolic responses. In warm water, minor postural changes and movement made flow under suits much higher, approximately 60 on trunk and 30 W . m-2 . degrees C-1 on limbs, both at rest and at work. These changes in flow allowed for a wide range of water temperatures at which people could stabilize body temperature in any given suit, neither overheating when exercising nor cooling below 35 degrees C when still. Even thin people with 4- or 7- mm suits covering the whole body could stabilize their body temperatures in water near 10 degrees C in spite of cold vasodilatation. Equations to predict limits of water temperature for stability with various suits and fat thicknesses are given.

Changes in body temperature and basal metabolic rate of the ama

1963 ◽  
Vol 18 (3) ◽  
pp. 483-488 ◽  
Author(s):  
B. S. Kang ◽  
S. H. Song ◽  
C. S. Suh ◽  
S. K. Hong
Keyword(s):  
Body Temperature ◽  
Metabolic Rate ◽  
Water Temperature ◽  
Basal Metabolic Rate ◽  
Cold Water ◽  
Four Seasons ◽  
Before And After ◽  
Average Skin ◽  
Skin Temperatures ◽  
Average Body

Oral temperatures of Korean diving women (ama) were measured before and after diving work in four seasons of the year. Their basal metabolic rate, measured in four seasons, was compared to that of nondiving women who lived in the same community and ate the same diet as the ama. Average oral temperatures declined to 35 C after 70 min of work in summer (water temp., 27 C) and to 33 C after 15 min of work in the winter (water temp., 10 C). Average body temperature, computed from weighted oral and average skin temperatures, declined to 34.6 C in summer and to 30 C in winter. Duration of work periods was determined principally by water temperature, since oral temperature declined at a rate inversely proportional to water temperature. The lower deep body temperatures which the ama endure in winter do, however, prolong their winter work period. The BMR of nondiving women was the same as the Dubois standard throughout the year. However, the BMR of ama varied with the season, ranging from +5 of the Dubois standard in summer to +35 in winter. We conclude that the elevated BMR of ama during the winter is cold adaptation, induced by repeated immersion in cold water. Submitted on November 23, 1962

Some aspects of body temperature regulation in sheep

1968 ◽  
Vol 71 (1) ◽  
pp. 61-66 ◽  
Author(s):  
M. E. D. Webster ◽  
K. G. Johnson
Keyword(s):  
Body Temperature ◽  
Surface Area ◽  
Cold Water ◽  
The Body ◽  
Body Temperatures ◽  
Mean Body Temperature ◽  
Merino Sheep ◽  
Infra Red ◽  
Heat Increment ◽  
Skin Temperatures

SummarySkin temperatures, deep body temperatures and respiratory rates have been measured in Southdown and Merino sheep following feeding, and during infra-red irradiation, rumen infusions of hot and cold water, and cold exposure induced by shearing. The increases in respiratory rate and skin temperatures induced by infra-red heating and the heat increment of feeding were reversed by addition of iced water to the rumen and were suppressed by shearing. These responses could not be systematically related to particular body temperatures in the sheep and appeared to be continuously variable rather than ‘all-or-none’ phenomena. Considerable overlap was observed between respiratory and vasomotor mechanisms of thermoregulation. Measurements of the surface area and weight of ears and legs showed that these regions contribute approximately 23% of the surface area and 8% of the body weight in Merino sheep. Calculations suggested that up to 70% of the additional heat produced in the 2 h after feeding in sheep may be stored in the tissues through increase in mean body temperature. Sheep kept in short wool throughout the winter appeared to establish a new thermoregulatory ‘set-point’ associated with lower rectal temperatures than those in sheep with a full fleece.

scholarly journals The metabolic response of the Bradypus sloth to temperature

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5600 ◽  
Author(s):  
Rebecca Naomi Cliffe ◽  
David Michael Scantlebury ◽  
Sarah Jane Kennedy ◽  
Judy Avey-Arroyo ◽  
Daniel Mindich ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Body Temperature ◽  
Energy Expenditure ◽  
High Power ◽  
Metabolic Response ◽  
Metabolic Responses ◽  
Metabolic Depression ◽  
Wide Range ◽  
Energetic Constraints ◽  
Power Costs

Poikilotherms and homeotherms have different, well-defined metabolic responses to ambient temperature (Ta), but both groups have high power costs at high temperatures. Sloths (Bradypus) are critically limited by rates of energy acquisition and it has previously been suggested that their unusual departure from homeothermy mitigates the associated costs. No studies, however, have examined how sloth body temperature and metabolic rate vary with Ta. Here we measured the oxygen consumption (VO2) of eight brown-throated sloths (B. variegatus) at variable Ta’s and found that VO2 indeed varied in an unusual manner with what appeared to be a reversal of the standard homeotherm pattern. Sloth VO2 increased with Ta, peaking in a metabolic plateau (nominal ‘thermally-active zone’ (TAZ)) before decreasing again at higher Ta values. We suggest that this pattern enables sloths to minimise energy expenditure over a wide range of conditions, which is likely to be crucial for survival in an animal that operates under severe energetic constraints. To our knowledge, this is the first evidence of a mammal provisionally invoking metabolic depression in response to increasing Ta’s, without entering into a state of torpor, aestivation or hibernation.

Dual core and shell temperature regulation during sea acclimatization in Gentoo penguins (Pygoscelis papua)

1994 ◽  
Vol 266 (4) ◽  
pp. R1319-R1326 ◽  
Author(s):  
E. Dumonteil ◽  
H. Barre ◽  
J. L. Rouanet ◽  
M. Diarra ◽  
J. Bouvier
Keyword(s):  
Body Temperature ◽  
Metabolic Rate ◽  
Thermal Insulation ◽  
Cold Water ◽  
Threshold Temperature ◽  
Ambient Temperatures ◽  
Adaptation To Cold ◽  
Marine Life ◽  
Shell Temperature ◽  
Skin Temperatures

Penguins are able to maintain a high and constant body temperature despite a thermally constraining environment. Evidence for progressive adaptation to cold and marine life was sought by comparing body and peripheral skin temperatures, metabolic rate, and thermal insulation in juvenile and adult Gentoo penguins exposed to various ambient temperatures in air (from -30 to +30 degrees C) and water (3-35 degrees C). Juvenile penguins in air showed metabolic and insulative capacities comparable with those displayed by adults. Both had a lower critical temperature (LCT) close to 0 degree C. In both adults and juveniles, the intercept of the metabolic curve with the abscissa at zero metabolic rate was far below body temperature. This was accompanied by a decrease in thermal insulation below LCT, allowing the preservation of a threshold temperature in the shell. However, this shell temperature maintenance was progressively abandoned in immersed penguins as adaptation to marine life developed, probably because of its prohibitive energy cost in water. Thus adaptation to cold air and to cold water does not rely on the same kind of reactions. Both of these strategies fail to follow the classical sequence linking metabolic and insulative reactions in the cold.

Thermal relations of the malle fragon Amphibolurus fordi (Lacertilia : Agamidae)

1974 ◽  
Vol 22 (3) ◽  
pp. 319 ◽  
Author(s):  
HG Cogger
Keyword(s):  
Body Temperature ◽  
Field Study ◽  
New South ◽  
Close Association ◽  
The Body ◽  
Total Effect ◽  
Body Temperatures ◽  
South Wales ◽  
Wide Range ◽  
Thermal Relations

A field study of the thermal relationships of the small agamid lizard A. fordi has been carried out in two areas of mallee in central western New South Wales, where this lizard occurs only in close association with the grass Triodia scariosa. The body temperatures characteristic of various phases in this lizard's die1 cycle have been determined. The behavioural techniques employed to regulate temperature are described; they are similar to those used by a wide range of diurnal heliothermic lizards in other regions. The total effect of these thermoregulatory responses is to maintain an internal thermal environ- ment approaching homoiothermy while the lizard is active. For A. fordi the eccritic body temperature determined from animals in the field is 36.9+-0.16C. Lowering of activity thermal levels occurs in winter, and can be induced at any time by even mild starvation.

Body temperature fluctuations in free-ranging eastern foxsnakes (Elaphe gloydi) during cold-water swimming

2006 ◽  
Vol 84 (1) ◽  
pp. 9-19 ◽  
Author(s):  
Carrie A MacKinnon ◽  
Anna Lawson ◽  
E D Stevens ◽  
Ronald J Brooks
Keyword(s):  
Body Temperature ◽  
Water Temperature ◽  
Swimming Speed ◽  
Cold Water ◽  
Temperature Fluctuations ◽  
Temperature Sensitive ◽  
Clear Trend ◽  
Thermal Biology ◽  
Rapid Temperature ◽  
Free Ranging

We examined the thermal biology of free-ranging terrestrial eastern foxsnakes (Elaphe gloydi Conant, 1940) that were voluntarily swimming in cold water during spring, in Georgian Bay, Ontario, Canada. Using temperature-sensitive radiotelemetry, we recorded body temperatures of foxsnakes during 12 cold-water swims, and subsequent warming on shore. During these swims, water temperatures were from 11 to 22 °C and distances of 85–1330 m were travelled. Snakes that were in cold water long enough equilibrated with water temperature and did not maintain a body temperature above ambient. The largest observed drop in body temperature was 22.6 °C (over 11 min) and the largest increase was 23 °C (over 66 min). Such large, rapid temperature fluctuations have not previously been reported in detail from snakes in the field. Twice as many telemetry observations as expected occurred between 1200 and 1400, suggesting that snakes chose to swim midday. Additionally, our results suggest that foxsnakes bask to raise their body temperature prior to swimming in cold water. We compared swimming speed and the coefficient of temperature change among foxsnakes and other snake species. Swimming speed was positively correlated with water temperature, similar to other findings. We found no clear trend between mass and the coefficients of cooling and warming; however, snakes cooled in water 2.8–8.6 times faster than they warmed in air.

scholarly journals Heart rate reveals torpor at high body temperatures in lowland tropical free-tailed bats

2017 ◽  
Vol 4 (12) ◽  
pp. 171359 ◽  
Author(s):  
M. Teague O'Mara ◽  
Sebastian Rikker ◽  
Martin Wikelski ◽  
Andries Ter Maat ◽  
Henry S. Pollock ◽  
...  
Keyword(s):  
Heart Rate ◽  
Body Temperature ◽  
Metabolic Rate ◽  
Ambient Temperature ◽  
The Body ◽  
Metabolic Rates ◽  
Body Temperatures ◽  
Wide Range ◽  
Save Energy ◽  
Molossus Molossus

Reduction in metabolic rate and body temperature is a common strategy for small endotherms to save energy. The daily reduction in metabolic rate and heterothermy, or torpor, is particularly pronounced in regions with a large variation in daily ambient temperature. This applies most strongly in temperate bat species (order Chiroptera), but it is less clear how tropical bats save energy if ambient temperatures remain high. However, many subtropical and tropical species use some daily heterothermy on cool days. We recorded the heart rate and the body temperature of free-ranging Pallas' mastiff bats ( Molossus molossus ) in Gamboa, Panamá, and showed that these individuals have low field metabolic rates across a wide range of body temperatures that conform to high ambient temperature. Importantly, low metabolic rates in controlled respirometry trials were best predicted by heart rate, and not body temperature . Molossus molossus enter torpor-like states characterized by low metabolic rate and heart rates at body temperatures of 32°C, and thermoconform across a range of temperatures. Flexible metabolic strategies may be far more common in tropical endotherms than currently known.

scholarly journals On the heating and cooling of the body by local application of heat and cold

1922 ◽  
Vol 93 (651) ◽  
pp. 207-212
Keyword(s):  
Body Temperature ◽  
Beneficial Effect ◽  
Cold Water ◽  
The Body ◽  
Hot Water ◽  
Local Application ◽  
Whole Body ◽  
Local Cooling ◽  
Heating And Cooling ◽  
Stimulation Of

The object of this enquiry is to find out how much heat can be gained, or cold lost from the body, by the local cooling or warming of a small part, by cooling the hands in a stream of cold water, warming the feet in a hot foot­ bath, or by a foot-warmer. In order to secure the beneficial effect of open windows, the breathing of cool air of low-vapour tension, and stimulation of body metabolism by such air ventilating the clothed and naked parts of the skin, the general heating of rooms by hot-water coils might be replaced by small heaters kept a few degrees above body temperature and locally applied to each individual, and each under the individual’s control. Electric heaters have been used by aeroplanists placed beneath their outer garments. One of us(l) recently published results showing that heating or cooling the hands can effectively heat or cool the whole body. We record further experiments of a like nature.

Ventilatory and metabolic responses to hypoxia during moderate hypothermia in anesthetized rats

1995 ◽  
Vol 79 (1) ◽  
pp. 256-260 ◽  
Author(s):  
P. Frappell ◽  
K. Westwood ◽  
M. Maskrey
Keyword(s):  
Body Temperature ◽  
Metabolic Rate ◽  
Heat Exchangers ◽  
Metabolic Responses ◽  
Moderate Hypothermia ◽  
O2 Consumption ◽  
Direct Effects ◽  
Body Temperatures ◽  
Anesthetized Rats ◽  
Per Se

In resting euthermic mammals, hypoxia elicits a hyperventilation that results from a combination of hyperpnea and hypometabolism. Often accompanying the hypoxia-induced hypometabolism is a drop in body temperature. To separate the synergic effects of hypothermia per se from the direct effects of hypoxia on metabolic rate, ventilation (VE), and O2 consumption (VO2) were measured in anesthetized rats fitted with abdominal heat exchangers and maintained at either normothermic (37.5 degrees C) or hypothermic (35 degrees C) body temperatures while exposed to either normoxia or hypoxia (7% O2). Hypothermia induced parallel decreases in VE and VO2, thereby maintaining VE/VO2. Hypoxia resulted in a hyperventilation achieved with the same relative decrease in VO2 and increase in VE in both normothermic and hypothermic rats. The results suggest that 1) the changes in metabolic rate and VE during hypothermia reflect a direct effect of cold and, 2) because of similar levels of hypoxic hyperventilation in the hypothermic and normothermic rats, relative to metabolic rate, respiratory gain has not been depressed in hypothermic rats.

Body temperature of free-living freshwater turtles, Hydromedusa maximiliani (Testudines, Chelidae)

2006 ◽  
Vol 27 (3) ◽  
pp. 464-468 ◽  
Author(s):  
Fernando Martins ◽  
Franco Souza
Keyword(s):  
Body Temperature ◽  
Water Temperature ◽  
Stream Water ◽  
Life Stage ◽  
Freshwater Turtle ◽  
Freshwater Turtles ◽  
Body Temperatures ◽  
Turtle Species ◽  
Mountainous Regions ◽  
Main Factor

AbstractField body temperatures of the Maximilian's snake-necked turtle, Hydromedusa maximiliani, a small freshwater turtle species endemic to Atlantic rainforest mountainous regions in Brazil, were studied. Turtle body temperatures and water temperatures were significantly related, but turtle body temperature averaged 1°C higher than stream water temperature, this difference being statistically significant. A multivariate model revealed that only water temperature was significantly related to turtle body temperature while body size had no effect. There was no effect of sex and life stage on turtle body temperature, implying that water temperature was the main factor determining body temperatures. Thermoconformity was verified for all sampled individuals. The broad implications of these results are also discussed.

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