Energy exchanges of swimming man.

Nadel, E. R.; Holmér, I; Bergh, Ulf; Astrand, P.-O.; Stolwijk, J. A. J.

doi:10.1152/jappl.1974.36.4.465

Cited by 145 publications

(80 citation statements)

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“…Water immersion however, provides an ideal medium to observe surface heat transfer and therefore to examine the effects of AD-wt-l upon thermal responses. The convective heat transfer coefficient both theoretical (Rapp 1971) and measured (Boutelier et al 1977;Nadel et al 1974) is high in water, and the effective surface area in contact with the environment is greater in water than in air (Molnar 1946). Ther' e, the skin temperature is uniform and approximates the water tempera, *a*…”

Section: Resultsmentioning

confidence: 99%

Effects of body mass and morphology on thermal responses in water

Toner¹,

Sawka²,

Foley³

et al. 1986

Journal of Applied Physiology

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Ten male volunteers were divided into two groups based on body morphology and mass. The large-body mass (LM) group (n = 5) was 16.3 kg heavier and 0.22 cm2 X kg-1 X 10(-2) smaller in surface area-to-mass ratio (AD X wt-1) (P less than 0.05) than the small-body mass (SM) group (n = 5). Both groups were similar in total body fat and skinfold thicknesses (P greater than 0.05). All individuals were immersed for 1 h in stirred water at 26 degrees C during both rest and one intensity of exercise (metabolic rate approximately 550 W). During resting exposures metabolic rate (M) and rectal temperature (Tre) were not different (P greater than 0.05) between the LM and SM groups at min 60. Esophageal temperature (Tes) was higher (P less than 0.05) for the SM group at min 60, although the change in Tes during the 60 min between groups was similar (LM, -0.4 degrees C; SM, -0.2 degrees C). Tissue insulation (I) was lower (P less than 0.05) for SM (0.061 degrees C X m-2 X W-1) compared with the LM group (0.098 degrees C X m-2 X W-1). During exercise M, Tre, Tes, and I were not different (P greater than 0.05) between groups at min 60. These data illustrate that a greater body mass between individuals increases the overall tissue insulation during rest, most likely as a result of a greater volume of muscle tissue to provide insulation.(ABSTRACT TRUNCATED AT 250 WORDS)

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Section: Resultsmentioning

confidence: 99%

Effects of body mass and morphology on thermal responses in water

Toner¹,

Sawka²,

Foley³

et al. 1986

Journal of Applied Physiology

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show abstract

“…Also, immersion in cold water elicits differing core temperatures indicating that chest cavity temperature is maintained at a higher level than other core areas. tion provided by this water boundary layer (19).…”

Section: Security Classification Of This Page(whaa Data Entmed)mentioning

confidence: 99%

“…[ In addition to insulation, core temperature responses of individuals immersed in various T have been shown to be dependent upon the particular w exercise intensity (6,19,26). It appears that the higher T response from re high intensity exercise may be explained in part by the return of heat that is liberated in the exercising muscles to the core for core temperature maintenance rather than loss of this heat to the environment (26).…”

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confidence: 99%

Comparison of thermal responses between rest and leg exercise in water

Toner¹,

Sawka²,

Holden³

et al. 1985

Journal of Applied Physiology

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This study examined both the thermal and metabolic responses of individuals in cool (30 degrees C, n = 9) and cold (18 degrees C, n = 7; 20 degrees C, n = 2) water. Male volunteers were immersed up to the neck for 1 h during both seated rest (R) and leg exercise (LE). In 30 degrees C water, metabolic rate (M) remained unchanged over time during both R (115 W, 60 min) and LE (528 W, 60 min). Mean skin temperature (Tsk) declined (P less than 0.05) over 1 h during R, while Tsk was unchanged during LE. Rectal (Tre) and esophageal (Tes) temperatures decreased (P less than 0.05) during R (delta Tre, -0.5 degrees C; delta Tes, -0.3 degrees C) and increased (P less than 0.05) during LE (delta Tre, 0.4 degrees C; Tsk, 0.4 degrees C). M, Tsk, Tre, and Tes were higher (P less than 0.05) during LE compared with R. In cool water, all regional heat flows (leg, chest, and arm) were generally greater (P less than 0.05) during LE than R. In cold water, M increased (P less than 0.05) over 1 h during R but remained unchanged during LE. Tre decreased (P less than 0.05) during R (delta Tre, -0.8 degrees C) but was unchanged during LE. Tes declined (P less than 0.05) during R (delta Tes, -0.4 degrees C) but increased (P less than 0.05) during LE (delta Tes, 0.2 degrees C). M, Tre, and Tes were higher (P less than 0.05), whereas Tsk was not different during LE compared with R at 60 min.

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“…The heat transferred to the medium next to the body can be swept away in a forced convection process with water or air passing by the seal's body surface. The heat capacity of a given volume of water is higher than that of the same volume of air by a factor of almost 3500, and the heat conductivity of water exceeds that of air by a factor of approximately 25 (but compare Nadel, 1984). These differences lead to considerably higher heat-transfer rates from a seal's warm body surfaces in water as compared with in air.…”

Section: Introductionmentioning

confidence: 97%

Thermal windows on the trunk of hauled-out seals: hot spots for thermoregulatory evaporation?

Mauck

Bilgmann

Jones

et al. 2003

Journal of Experimental Biology

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SUMMARY Seals have adapted to the high heat transfer coefficient in the aquatic environment by effective thermal insulation of the body core. While swimming and diving, excess metabolic heat is supposed to be dissipated mainly over the sparsely insulated body appendages, whereas the location of main heat sinks in hauled-out seals remains unclear. Here, we demonstrate thermal windows on the trunk of harbour seals, harp seals and a grey seal examined under various ambient temperatures using infrared thermography. Thermograms were analysed for location, size and development of thermal windows. Thermal windows were observed in all experimental sessions, shared some common characteristics in all seals and tended to reappear in similar body sites of individual seals. Nevertheless, the observed variations in order and location of appearance,number, size and shape of thermal windows would imply no special anatomical site for this avenue of heat loss. Based on our findings, we suggest that, in hauled-out seals, heat may be transported by blood flow to a small area of the wet body surface where the elevation of temperature facilitates evaporation of water trapped within the seals' pelages due to increased saturation vapour pressure. The comparatively large latent heat necessary for evaporation creates a temporary hot spot for heat dissipation.

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Energy exchanges of swimming man.

Cited by 145 publications

References 0 publications

Effects of body mass and morphology on thermal responses in water

Effects of body mass and morphology on thermal responses in water

Comparison of thermal responses between rest and leg exercise in water

Thermal windows on the trunk of hauled-out seals: hot spots for thermoregulatory evaporation?

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