Superficial shell insulation in resting and exercising men in cold water

1982 ◽  
Vol 52 (6) ◽  
pp. 1557-1564 ◽  
Author(s):  
A. Veicsteinas ◽  
G. Ferretti ◽  
D. W. Rennie
Keyword(s):  
Metabolic Rate ◽  
Water Temperature ◽  
Cold Water ◽  
Subcutaneous Fat ◽  
Skin Surface ◽  
Whole Body ◽  
Thermal Resistivity ◽  
Surface Areas ◽  
Body Regions

From measurements of subcutaneous fat temperature (Tsf) at known depths below the surface, skin surface temperature (Tsk), and direct skin heat flux (H), the superficial shell isulation (Iss) of the thigh (fat + skin) was calculated as Iss (degrees C.m2.w-1) = (Tsf - Tsk)/H in nine male subjects immersed head out in a well-stirred water bath. Also, at critical water temperature (CWT = 28–33 degrees C), eight of the subjects rested for 3 h, enabling overall maximal tissue insulation (It,max) to be calculated as It,max (degrees C.m2.W-1) = (Tre - Tw)/(0.92 M +/- delta S), where Tre is rectal temperature, Tw is water temperature, M is metabolic rate, and s is loss or gain of body heat. Five subjects performed up to 2 h of mild leg cycling, preceded and followed by 60 min of rest, and both thigh Iss and overall It were measured during exercise. Iss increased from minimal values in Tw greater than 33 degrees C to maximal values (Iss,max) at CWT or below. Iss,max was linearly related to tissue thickness (d) in millimeters of fat plus skin, Iss,max (degrees C.m2.W-1) = 0.0048d-0.0052; r = 0.95, n = 37, and was not influenced by leg exercise up to a metabolic rate of 150 W.m-2 in CWT despite large increases in Tsf and H and large decreases in overall It. The slope of Iss,max vs. depth, 0.0048 degrees C.m2.W-1.mm-1, is almost identical to thermal resistivity of fat in vitro, suggesting that the superficial shell is unperfused in CWT at rest or during mild exercise. When maximal superficial shell insulation (It,ss,max) for the whole body was calculated with allowance for differing fat thicknesses and surface areas of body regions, it could account for only 10–15% of overall It,max at rest and 35–40% of overall It in mild exercise. We suggest that the poorly perfused muscle shell plays a more important role as a defense against cooling at CWT than does the superficial shell (fat + skin), particularly at rest.

Conductive and convective heat flows of exercising humans in cold water

1989 ◽  
Vol 67 (6) ◽  
pp. 2473-2480 ◽  
Author(s):  
G. Ferretti ◽  
A. Veicsteinas ◽  
D. W. Rennie
Keyword(s):  
Heat Flow ◽  
Water Temperature ◽  
Convective Heat ◽  
Rectal Temperature ◽  
Cold Water ◽  
Subcutaneous Fat ◽  
Skin Surface ◽  
Heat Flows

The apparent conductance (Kss, in W.m-2.degrees C-1) of a given region of superficial shell (on the thigh, fat + skin) was determined on four nonsweating and nonshivering subjects, resting and exercising (200 W) in water [water temperature (Tw) 22-23 degrees C] Kss = Hss/(Tsf-Tsk) where Hss is the skin-to-water heat flow directly measured by heat flow transducers and Tsf and Tsk are the temperatures of the subcutaneous fat at a known depth below the skin surface and of the skin surface, respectively. The convective heat flow (qc) through the superficial shell was then estimated as qc = (Tsf - Tsk).(Kss - Kss,min), assuming that at rest Kss was minimal (Kss,min) and resting qc = 0. The duration of immersion was set to allow rectal temperature (Tre) to reach approximately 37 degrees C at the end of rest and approximately 38 degrees C at the end of exercise. Except at the highest Tw used, Kss at the start of exercise was always Kss,min and averaged 51 W.m-2.degrees C-1 (range 33-57 W.m-2.degrees C-1) across subjects, and qc was zero. At the end of exercise at the highest Tw used for each subject, Kss averaged 97 W.m-2.degrees C-1 (range 77-108 W.m-2.degrees C-1) and qc averaged 53% (range 48-61%) of Hss (mean Hss = 233 W.m-2).(ABSTRACT TRUNCATED AT 250 WORDS)

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

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.

scholarly journals Influenza infection rewires energy metabolism and induces browning features in adipose cells and tissues

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Asma Ayari ◽  
Manuel Rosa-Calatrava ◽  
Steve Lancel ◽  
Johanna Barthelemy ◽  
Andrés Pizzorno ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
White Adipose Tissue ◽  
Influenza A ◽  
Energy Homeostasis ◽  
Influenza Infection ◽  
Subcutaneous Fat ◽  
Whole Body ◽  
Glucose And Lipid Metabolism ◽  
The Impact

AbstractLike all obligate intracellular pathogens, influenza A virus (IAV) reprograms host cell’s glucose and lipid metabolism to promote its own replication. However, the impact of influenza infection on white adipose tissue (WAT), a key tissue in the control of systemic energy homeostasis, has not been yet characterized. Here, we show that influenza infection induces alterations in whole-body glucose metabolism that persist long after the virus has been cleared. We report depot-specific changes in the WAT of IAV-infected mice, notably characterized by the appearance of thermogenic brown-like adipocytes within the subcutaneous fat depot. Importantly, viral RNA- and viral antigen-harboring cells are detected in the WAT of infected mice. Using in vitro approaches, we find that IAV infection enhances the expression of brown-adipogenesis-related genes in preadipocytes. Overall, our findings shed light on the role that the white adipose tissue, which lies at the crossroads of nutrition, metabolism and immunity, may play in influenza infection.

THE USE OF SMALL SKIN SURFACE AREAS FOR WHOLE BODY SWEATING ASSESSMENT

1965 ◽  
Vol 43 (6) ◽  
pp. 971-977 ◽  
Author(s):  
Arthur C. Custance
Keyword(s):  
Body Weight ◽  
Body Weight Loss ◽  
Total Body Weight ◽  
Skin Surface ◽  
Moisture Loss ◽  
Whole Body ◽  
Surface Areas ◽  
Short Period ◽  
The Subject ◽  
Total Body

It is possible to obtain a continuous record of the sweating rate of an active subject by monitoring changes in total body weight. However, elaborate equipment is required that is capable of accommodating the treadmill (or other exercising device) as well as the subject. The balance must be rugged enough to withstand the movements of the subject, yet sensitive enough to respond to small changes in weight. It would be a great convenience to be able, instead, to monitor small representative areas of the skin surface with confidence that they faithfully reflect whole body reactions.In this research, moisture loss from a representative area of the skin of the dorsum under a capsule covering 14 sq. cm was measured by an apparatus which automatically altered the flow of dry air to keep the humidity of the effluent constant. In four subjects exercising on a treadmill at 3.5 m.p.h. the correlation coefficient between the area under the curves so obtained and the total body weight loss was very high (more than 0.93), and there was also good correlation after sweating was partially suppressed by atropine. Short-period fluctuations were simultaneous and highly correlated between bilaterally symmetrical areas of skin. It is concluded that moisture loss from a single area of skin can be used to represent changes in the rate and pattern of sweating of the whole body.

scholarly journals Can the impacts of cold-water pollution on fish be mitigated by thermal plasticity?

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
M A Parisi ◽  
R L Cramp ◽  
M A Gordos ◽  
C E Franklin
Keyword(s):  
Water Pollution ◽  
Metabolic Rate ◽  
Water Temperature ◽  
Cold Water ◽  
Thermal Sensitivity ◽  
Exposure Period ◽  
Thermal Pollution ◽  
Locomotor Performance ◽  
Thermal Plasticity ◽  
The Impact

Abstract Increasingly, cold-water pollution (CWP) is being recognised as a significant threat to aquatic communities downstream of large, bottom-release dams. Cold water releases typically occur during summer when storage dams release unseasonably cold and anoxic hypolimnetic waters, which can decrease the temperature of downstream waters by up to 16°C. Depending on the release duration, these hypothermic conditions can persist for many months. The capacity of ectothermic species to tolerate or rapidly adjust to acute temperature changes may determine the nature and magnitude of the impact of CWP on affected species. This study assessed the impacts of an acute reduction in water temperature on the physiological function and locomotor performance of juvenile silver perch (Bidyanus bidyanus) and examined their capacity to thermally compensate for the depressive effects of low temperatures via phenotypic plasticity. Locomotor performance (Ucrit and Usprint) and energetic costs (routine and maximum metabolic rate) were measured at multiple points over a 10-week period following an abrupt 10°C drop in water temperature. We also measured the thermal sensitivity of metabolic enzymes from muscle samples taken from fish following the exposure period. Cold exposure had significant depressive effects on physiological traits, resulting in decreases in performance between 10% and 55%. Although there was partial acclimation of Ucrit (~35% increase in performance) and complete compensation of metabolic rate, this occurred late in the exposure period, meaning silver perch were unable to rapidly compensate for the depressive effects of thermal pollution. The results of this study have substantial implications for the management of cold water releases from large-scale dams and the conservation of native freshwater fish species, as this form of thermal pollution can act as a barrier to fish movement, cause reduced recruitment, ecological community shifts and disruptions to timing and success of reproduction.

scholarly journals In Vitro and In Vivo Study on Humans of Natural Compound Synergy as a Multifunctional Approach to Cellulite-Derived Skin Imperfections

Cosmetics ◽  
2020 ◽  
Vol 7 (2) ◽  
pp. 48
Author(s):  
Vincenzo Nobile ◽  
Enza Cestone ◽  
Francesco Puoci ◽  
Ileana Deponti ◽  
Marta Pisati ◽  
...  
Keyword(s):  
Proteolytic Enzymes ◽  
Oryza Sativa L ◽  
Subcutaneous Fat ◽  
Whole Body ◽  
Ananas Comosus ◽  
Controlled Clinical Trial ◽  
Hypolipidemic Effect ◽  
Double Blind ◽  
Study Results

Aim: The present study aimed to assess the efficacy of a nutraceutical ingredient, SelectSIEVE® Rainbow, based on botanical extracts, in ameliorating cellulite-derived skin imperfections and microcirculation. The nutritional supplement contained a mixture of Oryza sativa (L.), Citrus sinensis (L.) Osbeck, Ananas comosus (L.) Merr, and Actinidia chinensis Planch; all ingredients were botanicals that can be used in food supplements. Results: In vitro studies showed the high capacity of the supplement to have an anti-inflammatory, antioxidant, and hypolipidemic effect, accompanied by an interesting proteolytic activity. The randomized double-blind placebo-controlled clinical trial, carried out on 60 women during an 8-week treatment period, confirmed the in vitro study results. SelectSIEVE® Rainbow showed a whole-body shaping activity, with a reduction of the waist, hip, and tight circumference of 0.8, 0.65 and 0.72 cm, respectively. It also showed a reduction of subcutaneous fat mass of 1.24 mm and body weight, with an average of 0.7 kg and positive peaks of −2.9 kg. Skin health and appearance were also improved: +5.4% skin elasticity, +5.5% skin tonicity and +5.7% skin draining. Finally, the dermatological evaluation of the cellulite score and microcirculation showed an improvement in 57% and 60% of the subjects enrolled in the studies. Conclusions: This first study provides interesting inputs on the effectiveness of the nutraceutical complex standardized in polyphenols, anthocyanins and proteolytic enzymes to counteract cellulite blemishes and improve local microcirculation. The positive response encourages deeper studies and further investigation.

Aquatic thermoregulation of captive and free-ranging beavers (Castor canadensis)

1990 ◽  
Vol 68 (11) ◽  
pp. 2409-2416 ◽  
Author(s):  
Robert A. MacArthur ◽  
Alvin P. Dyck
Keyword(s):  
Metabolic Rate ◽  
Cold Water ◽  
Castor Canadensis ◽  
Resting Metabolic Rate ◽  
Whole Body ◽  
Passive Cooling ◽  
Metabolic Rates ◽  
The Mean ◽  
Free Ranging ◽  
Skin Temperatures

Abdominal cooling occurred in 91% of all aquatic excursions documented in free-ranging beavers during fall and winter. Kits aged 4–7 months cooled faster and spent less time foraging in 1–12 °C water than did animals > 1 year old. All beavers tested in the laboratory displayed abdominal cooling in 2–20 °C water, with maximal cooling rates recorded in a 5- to 7-week-old kit. Immersion in cold water induced strong peripheral cooling, though skin temperatures beneath the pelage remained within 4–5 °C of abdominal measurements. The resting metabolic rate of beavers > 1 year old was independent of water temperature between 19 and 31 °C, but increased proportionately at lower temperatures. Whole-body conductance of resting animals was on average 1.6–3.0 times higher in water than in air. Maximum testing metabolic rates in water varied from 1.8 to 2.4 times the mean resting thermoneutral rate in air. Our results suggest that beavers mitigate the thermogenic effort required in water by adopting a thermoregulatory strategy which combines avoidance of prolonged immersion with a tolerance to passive cooling.

scholarly journals Changes of Body Temperature and Heat in Cardiac Surgical Patients

1985 ◽  
Vol 13 (1) ◽  
pp. 12-17 ◽  
Author(s):  
Colin A. Shanks ◽  
Leonard D. Wade ◽  
Ronald Meyer ◽  
Carolyn J. Wilkinson
Keyword(s):  
Body Temperature ◽  
Pulmonary Artery ◽  
Metabolic Rate ◽  
Subcutaneous Fat ◽  
Skin Surface ◽  
Exponential Relationship ◽  
Vasodilator Therapy ◽  
Deep Body Temperature ◽  
Skin Temperatures ◽  
Deep Body

Changes in body temperature were assessed in ten adult patients undergoing surgery involving cardiopulmonary bypass (CPB) and induced hypothermia. Intraoperatively, in comparable time intervals before CPB and after rewarming, the patients lost body heat. Between the time of induction of anaesthesia and CPB, the temperature of blood in the pulmonary artery fell 1.46 (SD 0.28°C); between CPB and the end of surgery the fall was 1.55 (SD 0.86°C). The extent of spontaneous hypothermia did not correlate with the amount of subcutaneous fat. Hypothermia was induced to obtain a stable deep body temperature of 27.2 (SD 1.3)°C, when mean skin temperature averaged 2°C higher. The CPB machine returned approximately 2000 kJ of heat in the rewarming period, to produce pulmonary artery and mean skin temperatures of 37.1 (SD 0.7)°C and 31.4 (SD 2.1)°C respectively. Intraoperative deep body temperatures demonstrated the expected exponential relationship with metabolic rate. Postoperatively, increase in metabolic rate was associated with rising deep body and skin temperatures. Low resistance to the flow of heat toward the skin surface was demonstrated by low postoperative values for thermal insulation, which may indicate good peripheral perfusion seen during continuing vasodilator therapy.

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