Thermogenesis during rest and exercise in cold air

1995 ◽  
Vol 73 (8) ◽  
pp. 1149-1153 ◽  
Author(s):  
Vincent J. Paolone ◽  
Albert M. Paolone
Keyword(s):  
Body Temperature ◽  
Heat Production ◽  
Water Vapor Pressure ◽  
Body Core Temperature ◽  
Adrenergic Blockade ◽  
Nonshivering Thermogenesis ◽  
Experimental Conditions ◽  
Mean Body Temperature ◽  
Body Core ◽  
Rest And Exercise

Nine non-cold-acclimated subjects (5 female, 4 male, mean age 22.5 years) were studied to determine whether nonshivering thermogenesis contributes to cold-induced metabolic heat production during rest (50 min standing) and exercise (40 min treadmill walking) in 5 °C. Propranolol was administered orally (females, 60 mg, 1.12 mg∙kg−1; males, 80 mg, 0.96 mg∙kg−1) to block nonshivering thermogenesis. Measurements were taken at both 25 °C, 13.1 Torr (water vapor pressure; 1 Torr = 133.3 Pa) and 5 °C, 3.6 Torr, with sessions randomly assigned to be drug–neutral (DN), drug–cold (DC), placebo–neutral (PN), and placebo–cold (PC). Body core temperature was not different between any of the experimental conditions. Mean body temperature (5 °C, 32.2 ± 0.20 °C (±SEM); 25 °C, 35.3 ± 0.20 °C) and mean skin temperature (5 °C, 22.4 ± 0.70 °C; 25 °C, 31.4 ± 0.60 °C) were lower (p < 0.05) in the 5 °C than 25 °C environment (rest, exercise, drug (D), placebo (P), combined); while shivering (EMG) was higher (16.5 ± 3.9% above baseline) at 5 °C than 25 °C (15 ± 2.1% below baseline) (p < 0.05). The greater [Formula: see text] in 5 °C compared with 25 °C for the same condition is the thermoregulatory [Formula: see text]. [Formula: see text] (mL∙min−1) was lower (p < 0.05) on the D [Formula: see text] than on the P [Formula: see text] during rest and during exercise (D, 206.1 ± 63.7; P, 338.4 ± 46.7). The EMG was 21% above baseline in the DC, and 12% above baseline for PC (p > 0.05). These results suggest a nonshivering component to heat production during acute cold exposure, which can be blocked with propranolol.Key words: nonshivering thermogenesis, propranolol, β-adrenergic blockade, body temperature, exercise, shivering.

Desaturation of exhaled air in camels

1981 ◽  
Vol 211 (1184) ◽  
pp. 305-319 ◽  
Keyword(s):  
Drinking Water ◽  
Heat Exchange ◽  
Body Temperature ◽  
Water Vapour ◽  
Mechanical Model ◽  
Ambient Air ◽  
Body Core Temperature ◽  
Hygroscopic Properties ◽  
Exhaled Air ◽  
Body Core

We have found that camels can reduce the water loss due to evaporation from the respiratory tract in two ways: (1) by decreasing the temperature of the exhaled air and (2) by removal of water vapour from this air, resulting in the exhalation of air at less than 100% relative humidity (r. h.). Camels were kept under desert conditions and deprived of drinking water. In the daytime the exhaled air was at or near body core temperature, while in the cooler night exhaled air was at or near ambient air temperature. In the daytime the exhaled air was fully saturated, but at night its humidity might fall to approximately 75% r. h. The combination of cooling and desaturation can provide a saving of water of 60% relative to exhalation of saturated air at body temperature. The mechanism responsible for cooling of the exhaled air is a simple heat exchange between the respiratory air and the surfaces of the nasal passageways. On inhalation these surfaces are cooled by the air passing over them, and on exhalation heat from the exhaled air is given off to these cooler surfaces. The mechanism responsible for desaturation of the air appears to depend on the hygroscopic properties of the nasal surfaces when the camel is dehydrated. The surfaces give off water vapour during inhalation and take up water from the respiratory air during exhalation. We have used a simple mechanical model to demonstrate the effectiveness of this mechanism.

Impaired memory registration and speed of reasoning caused by low body temperature

1983 ◽  
Vol 55 (1) ◽  
pp. 27-31 ◽  
Author(s):  
S. R. Coleshaw ◽  
R. N. Van Someren ◽  
A. H. Wolff ◽  
H. M. Davis ◽  
W. R. Keatinge
Keyword(s):  
Cognitive Function ◽  
Body Temperature ◽  
Core Temperature ◽  
Body Core Temperature ◽  
Impaired Memory ◽  
Test Speed ◽  
Body Core

Volunteers′ body core temperatures were lowered by immersion in water at 15 degrees C. Aspects of cognitive function were subsequently tested after rewarming had been started in water at 41 degrees C when their skin was warm and they felt comfortable but their body core temperature remained low. Memory registration was found to be impaired progressively when core temperature fell from about 36.7 degrees C; at core temperatures of 34-35 degrees C the impairment caused loss of approximately 70% of data that could normally be retained. However, recall of previously learned data was not impaired at these core temperatures. On a two-digit calculation test, speed of performance was impaired by about 50% at a core temperature of 34-35 degrees C, but provided enough time was available, accuracy of performance was not reduced.

Selected Contribution: Ambient temperature for experiments in rats: a new method for determining the zone of thermal neutrality

2002 ◽  
Vol 92 (6) ◽  
pp. 2667-2679 ◽  
Author(s):  
Andrej A. Romanovsky ◽  
Andrei I. Ivanov ◽  
Yury P. Shimansky
Keyword(s):  
Ambient Temperature ◽  
Body Core Temperature ◽  
Body Parts ◽  
Experimental Conditions ◽  
Strong Negative Correlation ◽  
Liquid Crystal Thermography ◽  
Body Core ◽  
Definition Of ◽  
Operational Range ◽  
Rat Tail

There is a misbelief that the same animal has the same thermoneutral zone (TNZ) in different experimental setups. In reality, TNZ strongly depends on the physical environment and varies widely across setups. Current methods for determining TNZ require elaborate equipment and can be applied only to a limited set of experimental conditions. A new, broadly applicable approach that rapidly determines whether given conditions are neutral for a given animal is needed. Consistent with the definition of TNZ [the range of ambient temperature (Ta) at which body core temperature (Tc) regulation is achieved only by control of sensible heat loss], we propose three criteria of thermoneutrality: 1) the presence of high-magnitude fluctuations in skin temperature (Tsk) of body parts serving as specialized heat exchangers with the environment (e.g., rat tail), 2) the closeness of Tsk to the median of its operational range, and 3) a strong negative correlation between Tskand Tc. Thermocouple thermometry and liquid crystal thermography were performed in five rat strains at 13 Ta. Under the conditions tested (no bedding or filter tops, no group thermoregulation), the Ta range of 29.5–30.5°C satisfied all three TNZ criteria in Wistar, BDIX, Long-Evans, and Zucker lean rats; Zucker fatty rats had a slightly lower TNZ (28.0–29.0°C). Skin thermometry or thermography is a definition-based, simple, and inexpensive technique to determine whether experimental or housing conditions are neutral, subneutral, or supraneutral for a given animal.

The Mortality of Royal Naval Submariners 1960-1989

1997 ◽  
Vol 83 (1) ◽  
pp. 26-30
Author(s):  
J R House ◽  
Cathy Holmes ◽  
A J Allsopp
Keyword(s):  
Core Temperature ◽  
Damage Control ◽  
Heat Strain ◽  
Royal Navy ◽  
Effective Technique ◽  
Experimental Conditions ◽  
Mean Body Temperature ◽  
Body Core ◽  
In Fire ◽  
Lowered Body

AbstractThe effectiveness of hand immersion in water at l0°C, 20°C and 30°C as a technique for reducing heat strain in Royal Navy (RN) personnel has been investigated at the Institute of Naval Medicine (INM). Four subjects exercised at a moderate work rate, whilst wearing fire fi ghting clothing in an environmental chamber at 40°C. The subjects reached heat strain safety limits within 45 minutes of commencing work at which point they rested in the heat for 30 minutes whilst they underwent one of four experimental conditions: without intervention (control); or with their hands immersed in water at 10°C, 20°C or 30°C. The experiment was repeated on a further three days so that the subjects undertook each experimental condition in a balanced randomised order. During the control condition without hand immersion the subjects were unable to cool. Immersion of the hands in water (at l0°C, 20°C or 30°C) significantly (P <0.05) lowered body core (auditory canal) temperature within ten minutes. Assessing the effectiveness of this technique by the initial rates of core temperature reduction, revealed that immersion of the hands was more effective the colder the water. Following 20 minutes of hand immersion mean core temperature had dropped from 38.SC to: 36.9(standard deviation 0.19)°C, 37.3 (0.18)°C, and 37.8(0. 10)°C, in l0°C, 20°C and 30°C water respectivel y. Cooling powers estimated from changes in mean body temperature were 334, 307 and 113 watts using 10°C, 20°C and 30°C water respectively. These results indicate that hand immersion in water at a temperature of between 10°C and 30°C is an efficient means of cooling heat stressed personnel who have been exercising. This simple and effective technique may be applied to many industrial and military tasks to reduce heat strain, lower the risk of heat injury, and increase safe total work times in the heat. For the RN, hand immersion could be used in fire fighting, damage control and NBC operations where personnel alternately work and rest.

Control of respiratory evaporative heat loss in exercising goats

1979 ◽  
Vol 46 (5) ◽  
pp. 978-983 ◽  
Author(s):  
J. B. Mercer ◽  
C. Jessen
Keyword(s):  
Heat Loss ◽  
Core Temperature ◽  
Heat Exchangers ◽  
The Body ◽  
Body Core Temperature ◽  
Evaporative Heat Loss ◽  
Hypothalamic Temperature ◽  
Body Core ◽  
Total Body ◽  
Rest And Exercise

Investigations were carried out to determine whether a nonthermal input is involved in the control of respiratory evaporative heat loss (REHL) in exercising goats. Two goats were implanted with hypothalamic perfusion thermodes and three goats were implanted with intravascular heat exchangers to clamp hypothalamic temperature and total body core temperature, respectively. At 30 degrees C air temperature REHL was measured while the animals were resting or walking on a treadmill (3 km.h-1, 5 degrees gradient). When the hypothalamic temperature was clamped between 33.0 and 43.0 degrees C the slopes of the responses relating increased REHL to hypothalamic temperature were similar during rest and exercise. However, the threshold hypothalamic temperatures for the increased REHL responses were lower during exercise than at rest, presumably due to higher extrahypothalamic temperatures. When the body core temperature was clamped between 37.0 and 40.4 degrees C the slopes of the responses relating increased REHL to total body core temperature during exercise showed only minor differences compared to those at rest, none of them conclusively indicating nonthermal influences.

scholarly journals Prevention of Intraoperative Hypothermia in Laparoscopy by the Use of Body-Temperature and Humidified CO2: a Pilot Study

2019 ◽  
Vol 79 (09) ◽  
pp. 969-975
Author(s):  
Julia Wittenborn ◽  
Annika Clausen ◽  
Felix Zeppernick ◽  
Elmar Stickeler ◽  
Ivo Meinhold-Heerlein
Keyword(s):  
Body Temperature ◽  
Temperature Profile ◽  
Room Temperature ◽  
Body Core Temperature ◽  
Control Group ◽  
Study Group ◽  
Treatment And Prevention ◽  
Intraoperative Hypothermia ◽  
Body Core ◽  
Control Study

Abstract Introduction Hypothermia is defined as a decrease in body core temperature to below 36 °C. If intraoperative heat-preserving measures are omitted, a patientʼs temperature will fall by 1 – 2 °C. Even mild forms of intraoperative hypothermia can lead to a marked increase in morbidity and mortality. The temperature of the insufflation gas is usually disregarded in the treatment and prevention of hypothermia. This study was conducted to investigate the effect of body-temperature and humidified CO2 on the intraoperative temperature profile and avoidance of hypothermia in laparoscopic surgery. Material and Methods In this retrospective, non-randomised case control study, 110 patients whose planned operation lasted at least 60 minutes were identified from 376 patients by means of an algorithm. Dry (20% humidity) CO2 at room temperature was insufflated in 51 patients (control group). 59 patients were insufflated with humidified (98% humidity) CO2 at body temperature (37 °C) (study group). These conditions were achieved with the HumiGard MR860 Surgical Humidification System (Fisher & Paykel Healthcare Limited, Auckland, New Zealand). The intraoperative temperature profile was evaluated by measurements every 10 minutes. Statistical analysis was performed with IBM® SPSS® Statistics 23.0.0. Results The intraoperative temperature in the control group fell steadily, while a continuous rise in temperature was observed in the study group. Warming was demonstrated in the study group with a start-end temperature difference of 0.09 °C, which differed significantly from the control group, in which it was − 0.09 °C (p = 0.011). The middle-end difference of 0.11 °C showed even higher significance in favour of the warmed gas (p = 0.003). The rate of hypothermia at the start of the operation fell from 50 to 36% in the study group and increased from 36 to 42% in the control group. Conclusion These results show that the use of body-temperature and humidified insufflation gas for laparoscopy can help to prevent intraoperative hypothermia.

scholarly journals Association of core body temperature and peripheral blood flow of the hands with pain intensity, pressure pain hypersensitivity, central sensitization, and fibromyalgia symptoms

2021 ◽  
Vol 12 ◽  
pp. 204062232199725
Author(s):  
Antonio Casas-Barragán ◽  
Francisco Molina ◽  
Rosa María Tapia-Haro ◽  
María Carmen García-Ríos ◽  
María Correa-Rodríguez ◽  
...  
Keyword(s):  
Body Temperature ◽  
Core Temperature ◽  
Clinical Symptoms ◽  
Core Body Temperature ◽  
Body Core Temperature ◽  
Peripheral Blood Flow ◽  
Greater Trochanter ◽  
Body Core ◽  
Hypothenar Eminence ◽  
Core Body

Our aim was to analyse body core temperature and peripheral vascular microcirculation at skin hypothenar eminence of the hands and its relationship to symptoms in fibromyalgia syndrome (FMS). A total of 80 FMS women and 80 healthy women, matched on weight, were enrolled in this case–control study. Thermography and infrared thermometer were used for evaluating the hypothenar regions and core body temperature, respectively. The main outcome measures were pain pressure thresholds (PPTs) and clinical questionnaires. Significant associations were observed between overall impact [ β = 0.033; 95% confidence interval (95%CI) = 0.003, 0.062; p = 0.030], daytime dysfunction ( β = 0.203; 95%CI = 0.011, 0.395; p = 0.039) and reduced activity ( β = 0.045; 95%CI = 0.005, 0.085; p = 0.029) and core body temperature in FMS women. PPTs including greater trochanter dominant ( β = 0.254; 95%CI = 0.003, 0.504; p = 0.047), greater trochanter non-dominant ( β = 0.650; 95%CI = 0.141, 1.159; p = 0.013), as well as sleeping medication ( β = −0.242; 95%CI = −0.471, −0.013; p = 0.039) were also associated with hypothenar eminence temperature. Data highlighted that FMS women showed correlations among body core temperature and hand temperature with the clinical symptoms.

Effects of Hydration on Febrile Temperature Patterns in Rabbits

2001 ◽  
Vol 2 (4) ◽  
pp. 277-291 ◽  
Author(s):  
Charlotte A. Richmond
Keyword(s):  
Heart Rate ◽  
Body Temperature ◽  
Core Temperature ◽  
Cardiovascular Responses ◽  
Fluid Replacement ◽  
Body Core Temperature ◽  
Hydration Status ◽  
Beneficial Role ◽  
Fluid Supplementation ◽  
Body Core

Patients with fever have a predisposition to experience dehydration, which may alter their thermoregulatory responses to elevated body temperature. In view of the recent discovery of the antipyretic activity of arginine vasopressin (AVP), it is possible that dehydration has a beneficial role during fever. Dehydration may enhance endogenous antipyresis by stimulating AVP release, making aggressive fluid replacement, which may inhibit AVP release, undesirable during fever. This study addressed the effects of manipulation of hydration status on temperature and cardiovascular responses in endotoxin-injected rabbits. Eight unanesthetized chronically instrumented rabbits were exposed to lipopolysaccharide (LPS) while in euhydrated state, after furosemide (5 mg/kg) and 24 hours of water deprivation (dehydrated), after infusion of saline (30 mL/kg) while in euhydrated state (hyperhydrated), and after saline (mL/per overnight body weight loss in grams) while in dehydrated state (rehydrated). Dehydrated rabbits display higher fevers that are biphasic in nature and are accompanied by increased vasoconstriction and duration of mean arterial pressure increases, indicating that activation of antipyretic mechanisms in dehydrated rabbits was not sufficient to reduce body core temperature. In addition, fluid supplementation in euhydrated rabbits did not alter the febrile response; however, a marked decrease in heart rate was noted. Furthermore, fluid supplementation in dehydrated rabbits significantly attenuates the rectal temperature and heart rate response to LPS injection, indicating the possibility that activation of antipyretic mechanisms of AVP in rehydrated rabbits was sufficient to reduce body core temperature. The results suggest that fluid supplementation has a beneficial role in keeping body temperature lower.

scholarly journals An intra ruminal heat exchanger for use in large concious animals

Rangifer ◽  
1985 ◽  
Vol 5 (1) ◽  
pp. 10 ◽  
Author(s):  
James B. Mercer ◽  
Helge K. Johnsen ◽  
Svein D. Mathiesen ◽  
Arnoldus Schytte Blix
Keyword(s):  
Heat Exchanger ◽  
Core Temperature ◽  
Heat Production ◽  
The Body ◽  
Body Core Temperature ◽  
Ruminant Species ◽  
Large Ruminant ◽  
Body Core ◽  
Total Body

<p>A method is described whereby it is possible to alter total body core temperature independently of environmetal temperature and/or exercise in conscious reindeer. The method employs the use of a simple heat exchanger introduced through a permanent rumen fistula. The heat exchanger consists of a 7 m long coil of flexible plastic tubing (OD, 10.0 mm, ID, 8.0 mm). By perfusing the tubing with thermostatically controlled water, heat can be added to or subtracted from the body core at rates equalling several times resting heat production. It is suggested that the method could be used in any large ruminant species.</p><p>En intra-rumenal varmeveksler til bruk i st&oslash;rre, uanesteserte dyr.</p><p>Abstract in Norwegian / Sammendrag: Vi har i denne unders&oslash;kelsen beskrevet en metode for hvordan kroppstemperatur hos uanesteserte reinsdyr kan endres uavhengig av omgivelsestemperatur og om dyret l&oslash;per eller ikke. Metoden inneb&aelig;rer bruk av en enkel varmeveksler som plasseres i dyrets vom gjennom en permanent vom-fistel. Varmeveksleren best&aring;r av en 7 m lang kveil av fleksibel plastslange (ytre diameter 10.0 mm, indre diameter 8.0 mm). Ved &aring; perfundere slangen med vann av en bestemt temperatur er det mulig &aring; fjerne eller tilf&oslash;re kroppen en varmemengde som tilsvarer flere ganger dyrets varmeproduksjon. Vi mener at denne metoden kan tilpasses alle store dr&oslash;vtyggere.</p><p>Potsiin asetettavan l&aring;mpotilan muuttajan k&aring;ytto suurilla nukkumattomilla el&aring;imill&aring;.</p><p>Abstract in Finnish / Yhteenveto: Tutkimuksessa olemme kuvanneet menetelman, jolla voidaan muuttaa nukuttamattoman poron ruumiinl&aring;mpotilaa riippumatta ulkolampotilasta tai siita juokseeko el&aring;in vai ei. Menetelmassa k&aring;ytaan yksinkertaista l&aring;mpotilan muuttajaa, joka asetetaan elaimeen pysyyan potsifistulan kautta. L&aring;mpotilan muuttaja kasitt&aring;a 7 m pitkan muoviletkurullan (letkun halkaisija 10.6 mm, reian halkaisija" 8.0 mmJTTaytt&aring;m&aring;lla letku tietyn lampoisell&aring; vedella on mahdollista joko laskea tai nostaa ruumiin lampom&aring;&aring;r&aring;a niin, etta se vastaa moninkertaisesti elaimen omaa l&aring;mmontuottoa. Oletamme, etta menetelm&aring;a voidaan kaytta&aring; kaikille suurille m&aring;rehtijoille.</p>

Body temperature lability in sheep and goats during short-term exposures to heat and cold

1971 ◽  
Vol 77 (2) ◽  
pp. 267-272 ◽  
Author(s):  
K. G. Johnson
Keyword(s):  
Thermal Stress ◽  
Body Temperature ◽  
Respiratory Rate ◽  
Air Temperature ◽  
Domestic Animals ◽  
The Body ◽  
Body Core Temperature ◽  
Short Term ◽  
Temperature Changes ◽  
Body Core

SummaryPassive lability of body core temperature during brief exposures to thermal stress is an efficient means of thermoregulation which few species of domestic animals appear to utilize. The body temperature changes of 30 shorn sheep and 10 shorn goats have been measured during standard heat and cold exposures lasting 7 h. During exposures to heat, air temperature was increased from 20 °C to 45 °C then reduced again to 20 °C. Rectal temperatures of goats and Soay, Welsh Mountain, Merino and Clun Forest sheep rose by an average of 1·96 °C, 1·22 °C, 1·04 °C, 0·85 °C and 0·80 °C respectively. All animals had similar increases in respiratory rate. During exposures to cold, air temperature was reduced from 20 °C to about 6 °C then increased again to 20 °C. Rectal temperatures rose by 0·18–0·20 °C in goats and in all sheep except Soays in which they fell by 0·28 °C. All animals showed moderate to vigorous shivering. None of the animals exhibited passive body temperature lability as an adaptation to thermal stress.

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