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Glen P. Kenny - One of the best experts on this subject based on the ideXlab platform.
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short term exercise training does not improve whole body Heat loss when rate of Metabolic Heat production is considered
European Journal of Applied Physiology, 2010Co-Authors: Jill M. Stapleton, Daniel Gagnon, Glen P. KennyAbstract:We evaluated the effects of an 8-week exercise training program in previously sedentary individuals on whole-body Heat balance during exercise at a constant rate of Metabolic Heat production. Prior to and after 8 weeks of training, ten participants performed 60-min of cycling exercise at a constant rate of Heat production (~450 W) followed by 60-min of recovery, at 30°C and 15% relative humidity. Rate of total Heat loss was measured directly by whole-body calorimetry, while rate of Metabolic Heat production was measured simultaneously by indirect calorimetry. Esophageal (T es), skin blood flow (SkBF) and local sweat rate (LSR) were also measured continuously. The 8-week exercise training program elicited a 10% increase in maximal aerobic capacity (P < 0.001). Furthermore, exercise training reduced (P ≤ 0.05) baseline (37.10 ± 0.28 vs. 36.95 ± 0.24°C) and end-exercise (37.85 ± 0.30 vs. 37.55 ± 0.20°C) values for T es as well as onset thresholds for LSR (37.23 ± 0.26 vs. 36.96 ± 0.22°C, P < 0.001) and SkBF (37.16 ± 0.38 vs. 36.83 ± 0.26°C, P < 0.001). However, these improvements in thermoregulatory function did not translate into a greater rate of total Heat loss between the pre- and post-training exercise trials (P = 0.762). Furthermore, there were no differences in SkBF (P = 0.546) and LSR (P = 0.475) from pre- to post-training. Although physical training resulted in significant improvements of cardiorespiratory and thermoregulatory functions, these adaptations did not improve whole-body and local Heat loss responses during exercise performed at a given rate of Metabolic Heat production.
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Short-term exercise training does not improve whole-body Heat loss when rate of Metabolic Heat production is considered
European Journal of Applied Physiology, 2010Co-Authors: Jill M. Stapleton, Daniel Gagnon, Glen P. KennyAbstract:We evaluated the effects of an 8-week exercise training program in previously sedentary individuals on whole-body Heat balance during exercise at a constant rate of Metabolic Heat production. Prior to and after 8 weeks of training, ten participants performed 60-min of cycling exercise at a constant rate of Heat production (~450 W) followed by 60-min of recovery, at 30°C and 15% relative humidity. Rate of total Heat loss was measured directly by whole-body calorimetry, while rate of Metabolic Heat production was measured simultaneously by indirect calorimetry. Esophageal (T es), skin blood flow (SkBF) and local sweat rate (LSR) were also measured continuously. The 8-week exercise training program elicited a 10% increase in maximal aerobic capacity (P
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Short-term exercise training does not improve whole-body Heat loss when rate of Metabolic Heat production is considered
European journal of applied physiology, 2010Co-Authors: Jill M. Stapleton, Daniel Gagnon, Glen P. KennyAbstract:We evaluated the effects of an 8-week exercise training program in previously sedentary individuals on whole-body Heat balance during exercise at a constant rate of Metabolic Heat production. Prior to and after 8 weeks of training, ten participants performed 60-min of cycling exercise at a constant rate of Heat production (approximately 450 W) followed by 60-min of recovery, at 30 degrees C and 15% relative humidity. Rate of total Heat loss was measured directly by whole-body calorimetry, while rate of Metabolic Heat production was measured simultaneously by indirect calorimetry. Esophageal (T(es)), skin blood flow (SkBF) and local sweat rate (LSR) were also measured continuously. The 8-week exercise training program elicited a 10% increase in maximal aerobic capacity (P < 0.001). Furthermore, exercise training reduced (P
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sex related differences in evaporative Heat loss the importance of Metabolic Heat production
European Journal of Applied Physiology, 2008Co-Authors: Daniel Gagnon, Bruno Lemire, Glen P. KennyAbstract:We evaluated the hypothesis that different rates of Metabolic Heat production between sexes, during exercise at the same percentage of maximum oxygen consumption \( \left( {\dot{V}{\text{O}}_{2\max } } \right), \) give proportional differences in evaporative Heat loss. Seven males and seven females, exercised at 41.3 ± 2.7% \( \dot{V}{\text{O}}_{2\max } \) for 60-min at 40°C and 30% relative humidity. Whole-body direct air calorimetry measured rate of whole-body evaporative Heat loss \( \left( {\dot{H}_{\text{E}} } \right), \) while Metabolic Heat production \( \left( {\dot{M} - \dot{W}} \right) \) was measured by indirect calorimetry. \( \dot{M} - \dot{W} \) was greater in males (243 ± 18 W m−2) relative to females (201 ± 4 W m−2) (P ≤ 0.05) throughout exercise. This was paralleled by a greater \( \dot{H}_{\text{E}} \) at end-exercise in males (207 ± 51 W m−2) relative to females (180 ± 3 W m−2) (P ≤ 0.05). Differences in Metabolic Heat production between sexes during exercise at a fixed percentage of \( \dot{V}{\text{O}}_{2\max } \) give differences in evaporative Heat loss. To compare thermoregulatory function between sexes, differences in Metabolic Heat production must therefore be accounted for.
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Sex-related differences in evaporative Heat loss: the importance of Metabolic Heat production.
European journal of applied physiology, 2008Co-Authors: Daniel Gagnon, Bruno Lemire, Ollie Jay, Glen P. KennyAbstract:We evaluated the hypothesis that different rates of Metabolic Heat production between sexes, during exercise at the same percentage of maximum oxygen consumption [VO2 max] give proportional differences in evaporative Heat loss. Seven males and seven females, exercised at 41.3 +/- 2.7% VO2 Max for 60-min at 40 degrees C and 30% relative humidity. Whole-body direct air calorimetry measured rate of whole-body evaporative Heat loss (H e) while Metabolic Heat production (M - W) was measured by indirect calorimetry. M -W was greater in males (243 +/- 18 W m(-2)) relative to females (201 +/- 4 W m(-2)) (P
Daniel Gagnon - One of the best experts on this subject based on the ideXlab platform.
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short term exercise training does not improve whole body Heat loss when rate of Metabolic Heat production is considered
European Journal of Applied Physiology, 2010Co-Authors: Jill M. Stapleton, Daniel Gagnon, Glen P. KennyAbstract:We evaluated the effects of an 8-week exercise training program in previously sedentary individuals on whole-body Heat balance during exercise at a constant rate of Metabolic Heat production. Prior to and after 8 weeks of training, ten participants performed 60-min of cycling exercise at a constant rate of Heat production (~450 W) followed by 60-min of recovery, at 30°C and 15% relative humidity. Rate of total Heat loss was measured directly by whole-body calorimetry, while rate of Metabolic Heat production was measured simultaneously by indirect calorimetry. Esophageal (T es), skin blood flow (SkBF) and local sweat rate (LSR) were also measured continuously. The 8-week exercise training program elicited a 10% increase in maximal aerobic capacity (P < 0.001). Furthermore, exercise training reduced (P ≤ 0.05) baseline (37.10 ± 0.28 vs. 36.95 ± 0.24°C) and end-exercise (37.85 ± 0.30 vs. 37.55 ± 0.20°C) values for T es as well as onset thresholds for LSR (37.23 ± 0.26 vs. 36.96 ± 0.22°C, P < 0.001) and SkBF (37.16 ± 0.38 vs. 36.83 ± 0.26°C, P < 0.001). However, these improvements in thermoregulatory function did not translate into a greater rate of total Heat loss between the pre- and post-training exercise trials (P = 0.762). Furthermore, there were no differences in SkBF (P = 0.546) and LSR (P = 0.475) from pre- to post-training. Although physical training resulted in significant improvements of cardiorespiratory and thermoregulatory functions, these adaptations did not improve whole-body and local Heat loss responses during exercise performed at a given rate of Metabolic Heat production.
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Short-term exercise training does not improve whole-body Heat loss when rate of Metabolic Heat production is considered
European Journal of Applied Physiology, 2010Co-Authors: Jill M. Stapleton, Daniel Gagnon, Glen P. KennyAbstract:We evaluated the effects of an 8-week exercise training program in previously sedentary individuals on whole-body Heat balance during exercise at a constant rate of Metabolic Heat production. Prior to and after 8 weeks of training, ten participants performed 60-min of cycling exercise at a constant rate of Heat production (~450 W) followed by 60-min of recovery, at 30°C and 15% relative humidity. Rate of total Heat loss was measured directly by whole-body calorimetry, while rate of Metabolic Heat production was measured simultaneously by indirect calorimetry. Esophageal (T es), skin blood flow (SkBF) and local sweat rate (LSR) were also measured continuously. The 8-week exercise training program elicited a 10% increase in maximal aerobic capacity (P
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Short-term exercise training does not improve whole-body Heat loss when rate of Metabolic Heat production is considered
European journal of applied physiology, 2010Co-Authors: Jill M. Stapleton, Daniel Gagnon, Glen P. KennyAbstract:We evaluated the effects of an 8-week exercise training program in previously sedentary individuals on whole-body Heat balance during exercise at a constant rate of Metabolic Heat production. Prior to and after 8 weeks of training, ten participants performed 60-min of cycling exercise at a constant rate of Heat production (approximately 450 W) followed by 60-min of recovery, at 30 degrees C and 15% relative humidity. Rate of total Heat loss was measured directly by whole-body calorimetry, while rate of Metabolic Heat production was measured simultaneously by indirect calorimetry. Esophageal (T(es)), skin blood flow (SkBF) and local sweat rate (LSR) were also measured continuously. The 8-week exercise training program elicited a 10% increase in maximal aerobic capacity (P < 0.001). Furthermore, exercise training reduced (P
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sex related differences in evaporative Heat loss the importance of Metabolic Heat production
European Journal of Applied Physiology, 2008Co-Authors: Daniel Gagnon, Bruno Lemire, Glen P. KennyAbstract:We evaluated the hypothesis that different rates of Metabolic Heat production between sexes, during exercise at the same percentage of maximum oxygen consumption \( \left( {\dot{V}{\text{O}}_{2\max } } \right), \) give proportional differences in evaporative Heat loss. Seven males and seven females, exercised at 41.3 ± 2.7% \( \dot{V}{\text{O}}_{2\max } \) for 60-min at 40°C and 30% relative humidity. Whole-body direct air calorimetry measured rate of whole-body evaporative Heat loss \( \left( {\dot{H}_{\text{E}} } \right), \) while Metabolic Heat production \( \left( {\dot{M} - \dot{W}} \right) \) was measured by indirect calorimetry. \( \dot{M} - \dot{W} \) was greater in males (243 ± 18 W m−2) relative to females (201 ± 4 W m−2) (P ≤ 0.05) throughout exercise. This was paralleled by a greater \( \dot{H}_{\text{E}} \) at end-exercise in males (207 ± 51 W m−2) relative to females (180 ± 3 W m−2) (P ≤ 0.05). Differences in Metabolic Heat production between sexes during exercise at a fixed percentage of \( \dot{V}{\text{O}}_{2\max } \) give differences in evaporative Heat loss. To compare thermoregulatory function between sexes, differences in Metabolic Heat production must therefore be accounted for.
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Sex-related differences in evaporative Heat loss: the importance of Metabolic Heat production.
European journal of applied physiology, 2008Co-Authors: Daniel Gagnon, Bruno Lemire, Ollie Jay, Glen P. KennyAbstract:We evaluated the hypothesis that different rates of Metabolic Heat production between sexes, during exercise at the same percentage of maximum oxygen consumption [VO2 max] give proportional differences in evaporative Heat loss. Seven males and seven females, exercised at 41.3 +/- 2.7% VO2 Max for 60-min at 40 degrees C and 30% relative humidity. Whole-body direct air calorimetry measured rate of whole-body evaporative Heat loss (H e) while Metabolic Heat production (M - W) was measured by indirect calorimetry. M -W was greater in males (243 +/- 18 W m(-2)) relative to females (201 +/- 4 W m(-2)) (P
Jill M. Stapleton - One of the best experts on this subject based on the ideXlab platform.
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Short-term exercise training does not improve whole-body Heat loss when rate of Metabolic Heat production is considered
European Journal of Applied Physiology, 2010Co-Authors: Jill M. Stapleton, Daniel Gagnon, Glen P. KennyAbstract:We evaluated the effects of an 8-week exercise training program in previously sedentary individuals on whole-body Heat balance during exercise at a constant rate of Metabolic Heat production. Prior to and after 8 weeks of training, ten participants performed 60-min of cycling exercise at a constant rate of Heat production (~450 W) followed by 60-min of recovery, at 30°C and 15% relative humidity. Rate of total Heat loss was measured directly by whole-body calorimetry, while rate of Metabolic Heat production was measured simultaneously by indirect calorimetry. Esophageal (T es), skin blood flow (SkBF) and local sweat rate (LSR) were also measured continuously. The 8-week exercise training program elicited a 10% increase in maximal aerobic capacity (P
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short term exercise training does not improve whole body Heat loss when rate of Metabolic Heat production is considered
European Journal of Applied Physiology, 2010Co-Authors: Jill M. Stapleton, Daniel Gagnon, Glen P. KennyAbstract:We evaluated the effects of an 8-week exercise training program in previously sedentary individuals on whole-body Heat balance during exercise at a constant rate of Metabolic Heat production. Prior to and after 8 weeks of training, ten participants performed 60-min of cycling exercise at a constant rate of Heat production (~450 W) followed by 60-min of recovery, at 30°C and 15% relative humidity. Rate of total Heat loss was measured directly by whole-body calorimetry, while rate of Metabolic Heat production was measured simultaneously by indirect calorimetry. Esophageal (T es), skin blood flow (SkBF) and local sweat rate (LSR) were also measured continuously. The 8-week exercise training program elicited a 10% increase in maximal aerobic capacity (P < 0.001). Furthermore, exercise training reduced (P ≤ 0.05) baseline (37.10 ± 0.28 vs. 36.95 ± 0.24°C) and end-exercise (37.85 ± 0.30 vs. 37.55 ± 0.20°C) values for T es as well as onset thresholds for LSR (37.23 ± 0.26 vs. 36.96 ± 0.22°C, P < 0.001) and SkBF (37.16 ± 0.38 vs. 36.83 ± 0.26°C, P < 0.001). However, these improvements in thermoregulatory function did not translate into a greater rate of total Heat loss between the pre- and post-training exercise trials (P = 0.762). Furthermore, there were no differences in SkBF (P = 0.546) and LSR (P = 0.475) from pre- to post-training. Although physical training resulted in significant improvements of cardiorespiratory and thermoregulatory functions, these adaptations did not improve whole-body and local Heat loss responses during exercise performed at a given rate of Metabolic Heat production.
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Short-term exercise training does not improve whole-body Heat loss when rate of Metabolic Heat production is considered
European journal of applied physiology, 2010Co-Authors: Jill M. Stapleton, Daniel Gagnon, Glen P. KennyAbstract:We evaluated the effects of an 8-week exercise training program in previously sedentary individuals on whole-body Heat balance during exercise at a constant rate of Metabolic Heat production. Prior to and after 8 weeks of training, ten participants performed 60-min of cycling exercise at a constant rate of Heat production (approximately 450 W) followed by 60-min of recovery, at 30 degrees C and 15% relative humidity. Rate of total Heat loss was measured directly by whole-body calorimetry, while rate of Metabolic Heat production was measured simultaneously by indirect calorimetry. Esophageal (T(es)), skin blood flow (SkBF) and local sweat rate (LSR) were also measured continuously. The 8-week exercise training program elicited a 10% increase in maximal aerobic capacity (P < 0.001). Furthermore, exercise training reduced (P
Glenn E. Walsberg - One of the best experts on this subject based on the ideXlab platform.
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effect of wind and solar radiation on Metabolic Heat production in a small desert rodent spermophilus tereticaudus
The Journal of Experimental Biology, 2000Co-Authors: K M Wooden, Glenn E. WalsbergAbstract:To understand better how complex interactions between environmental variables affect the energy balance of small diurnal animals, we studied the effects of the absence and presence of 950 W m(−)(2) simulated solar radiation combined with wind speeds ranging from 0. 25 to 1.00 m s(−)(1) on the Metabolic rate and body temperature of the round-tailed ground squirrel Spermophilus tereticaudus. As wind speed increased from 0.25 to 1.00 m s(−)(1), Metabolic Heat production increased by 0.94 W in the absence of solar radiation and by 0.98 W in the presence of 950 W m(−)(2) simulated solar radiation. Exposure to simulated solar radiation reduced Metabolic Heat production by 0.68 W at a wind speed of 0.25 m s(−)(1), by 0.64 W at 0.50 m s(−)(1) and by 0.64 W at 1.00 m s(−)(1). Body temperature was significantly affected by environmental conditions, ranging from 32. 5 degrees C at a wind speed of 1.0 m s(−)(1) and no irradiance to 35. 6 degrees C at a wind speed of 0.50 m s(−)(1) with 950 W m(−)(2)short-wave irradiance. In addition, several unusual findings resulted from this study. The coat of S. tereticaudus is very sparse, and the observed Heat transfer of 5.68+/−0.37 W m(−)(2) degrees C(−)(1) (mean +/− s.e.m., N=11) is much higher than expected from either allometric equations or comparative studies with other rodents of similar mass. Solar Heat gain was remarkably low, equalling only 10 % of intercepted radiation and suggesting a remarkably high regional thermal resistance at the tissue level. Animals remained normally active and alert at body temperatures as low as 32.5 degrees C. These findings suggest a unique combination of adaptations that allow S. tereticaudus to exploit a harsh desert environment.
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effects of solar radiation and wind speed on Metabolic Heat production by two mammals with contrasting coat colours
The Journal of Experimental Biology, 1995Co-Authors: Glenn E. Walsberg, Blair O WolfAbstract:We report the first empirical data describing the interactive effects of simultaneous changes in irradiance and convection on energy expenditure by live mammals. Whole-animal rates of solar Heat gain and convective Heat loss were measured for representatives of two ground squirrel species, Spermophilus lateralis and Spermophilus saturatus, that contrast in coloration. Radiative Heat gain was quantified as the decrease in Metabolic Heat production caused by the animal’s exposure to simulated solar radiation. Changes in convective Heat loss were quantified as the variation in Metabolic Heat production caused by changes in wind speed. For both species, exposure to 780 Wm 2 2 of simulated solar radiation significantly
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Effects of solar radiation and wind speed on Metabolic Heat production by two mammals with contrasting coat colours.
The Journal of experimental biology, 1995Co-Authors: Glenn E. Walsberg, Blair O WolfAbstract:We report the first empirical data describing the interactive effects of simultaneous changes in irradiance and convection on energy expenditure by live mammals. Whole-animal rates of solar Heat gain and convective Heat loss were measured for representatives of two ground squirrel species, Spermophilus lateralis and Spermophilus saturatus, that contrast in coloration. Radiative Heat gain was quantified as the decrease in Metabolic Heat production caused by the animal's exposure to simulated solar radiation. Changes in convective Heat loss were quantified as the variation in Metabolic Heat production caused by changes in wind speed. For both species, exposure to 780 W m-2 of simulated solar radiation significantly reduced Metabolic Heat production at all wind speeds measured. Reductions were greatest at lower wind speeds, reaching 42% in S. lateralis and 29% in S. saturatus. Solar Heat gain, expressed per unit body surface area, did not differ significantly between the two species. This Heat gain equalled 14-21% of the radiant energy intercepted by S. lateralis and 18-22% of that intercepted by S. saturatus. Body resistance, an index of animal insulation, declined by only 10% in S. saturatus and 13% in S. lateralis as wind speed increased from 0.5 to 4.0 ms-1. These data demonstrate that solar Heat gain can be essentially constant, despite marked differences in animal coloration, and that variable exposure to wind and sunlight can have important consequences for both thermoregulatory stress experienced by animals and their patterns of energy allocation.
Blair O Wolf - One of the best experts on this subject based on the ideXlab platform.
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effects of solar radiation and wind speed on Metabolic Heat production by two mammals with contrasting coat colours
The Journal of Experimental Biology, 1995Co-Authors: Glenn E. Walsberg, Blair O WolfAbstract:We report the first empirical data describing the interactive effects of simultaneous changes in irradiance and convection on energy expenditure by live mammals. Whole-animal rates of solar Heat gain and convective Heat loss were measured for representatives of two ground squirrel species, Spermophilus lateralis and Spermophilus saturatus, that contrast in coloration. Radiative Heat gain was quantified as the decrease in Metabolic Heat production caused by the animal’s exposure to simulated solar radiation. Changes in convective Heat loss were quantified as the variation in Metabolic Heat production caused by changes in wind speed. For both species, exposure to 780 Wm 2 2 of simulated solar radiation significantly
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Effects of solar radiation and wind speed on Metabolic Heat production by two mammals with contrasting coat colours.
The Journal of experimental biology, 1995Co-Authors: Glenn E. Walsberg, Blair O WolfAbstract:We report the first empirical data describing the interactive effects of simultaneous changes in irradiance and convection on energy expenditure by live mammals. Whole-animal rates of solar Heat gain and convective Heat loss were measured for representatives of two ground squirrel species, Spermophilus lateralis and Spermophilus saturatus, that contrast in coloration. Radiative Heat gain was quantified as the decrease in Metabolic Heat production caused by the animal's exposure to simulated solar radiation. Changes in convective Heat loss were quantified as the variation in Metabolic Heat production caused by changes in wind speed. For both species, exposure to 780 W m-2 of simulated solar radiation significantly reduced Metabolic Heat production at all wind speeds measured. Reductions were greatest at lower wind speeds, reaching 42% in S. lateralis and 29% in S. saturatus. Solar Heat gain, expressed per unit body surface area, did not differ significantly between the two species. This Heat gain equalled 14-21% of the radiant energy intercepted by S. lateralis and 18-22% of that intercepted by S. saturatus. Body resistance, an index of animal insulation, declined by only 10% in S. saturatus and 13% in S. lateralis as wind speed increased from 0.5 to 4.0 ms-1. These data demonstrate that solar Heat gain can be essentially constant, despite marked differences in animal coloration, and that variable exposure to wind and sunlight can have important consequences for both thermoregulatory stress experienced by animals and their patterns of energy allocation.