Increased thermal body insulation: relationship to the development of obesity.

Jéquier, E; Gygax, P.; Pittet, Ph.; A, Vannotti

doi:10.1152/jappl.1974.36.6.674

Cited by 57 publications

(39 citation statements)

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“…It could be argued that greater adipose tissue may have contributed to the apparent reduction in the potential for heat dissipation in linemen. However, although a greater subcutaneous fat layer may have played a role in the slightly lower resting skin temperatures (35) observed in linemen before the start of exercise, beeause of a lower thermal conductivity (23), it is likely that any insulative fat layers were bypassed by blood fiow after the onset of exercise (21 )-a notion supported by similar absolute skin temperatures between position groups during exercise.…”

Section: Discussionmentioning

confidence: 99%

Sweating Is Greater in NCAA Football Linemen Independently of Heat Production

Deren

Coris

Bain

et al. 2012

Medicine &Amp; Science in Sports &Amp; Exercise

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Football linemen sweat significantly more on the torso and head than football backs independently of any differences in metabolic heat production per unit BSA and therefore the evaporative requirements for heat balance. Despite greater sweating, linemen demonstrated significantly greater elevations in core temperature suggesting that sweating efficiency (i.e., the proportion of sweat that evaporates) was much lower in linemen.

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Section: Discussionmentioning

confidence: 99%

Sweating Is Greater in NCAA Football Linemen Independently of Heat Production

Deren

Coris

Bain

et al. 2012

Medicine &Amp; Science in Sports &Amp; Exercise

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“…Ducharme and Tikuisis (13) demonstrated that muscle mass may account for up to 92% of I t in the forearm of young subjects, and it has been hypothesized that loss of muscle mass with aging may lead to lower I t (28), with the assumption that lower I t would then lead to an impaired defense of T c . I t is the result of the passive effects of adipose and muscle tissues coupled with the dynamic effects of skin and muscle blood flows (27). Either increased adiposity or muscle mass or decreased blood flow increases I t .…”

Section: Discussionmentioning

confidence: 99%

“…Either increased adiposity or muscle mass or decreased blood flow increases I t . However, Jequier et al (27) proposed that markedly obese subjects have less nonfat (i.e., muscle) insulation than normalweight subjects and suggested that changes in blood flow may be the mediating factor.…”

Section: Discussionmentioning

confidence: 99%

Responses to mild cold stress are predicted by different individual characteristics in young and older subjects

DeGroot¹,

Havenith²,

Kenney

2006

Journal of Applied Physiology

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ney. Responses to mild cold stress are predicted by different individual characteristics in young and older subjects. J Appl Physiol 101: 1607-1615, 2006. First published August 3, 2006 doi:10.1152/japplphysiol.00717.2006.-Older individuals' ability to maintain core temperature during cold stress is impaired; however, the relative importance of individual characteristics that influence this response are unknown. The purpose of this study was to determine the relative influence of individual characteristics on core temperature and tissue insulation (I t) during mild cold stress. Forty-two young (23 Ϯ 1 yr, range 18 -30 yr) and 46 older (71 Ϯ 1 yr, range 65-89 yr) subjects, varying widely in muscularity, adiposity, and body size, underwent a transient cooling protocol during which esophageal temperature (T es) was measured continuously and I t was calculated using standard equations. Multipleregression analyses were performed to determine predictors of T es and It, and standardized regression coefficients were analyzed to determine the relative influence of each predictor. Candidate predictors included age, sex, weight, body surface area, body surface area-to-mass ratio, sum of skinfolds, percent fat, appendicular skeletal muscle mass, and thyroid hormone concentrations (triiodothyronine, thyronine). The sum of skinfolds explained 67% (P Ͻ 0.01) of the T es variance in young subjects vs. 2% (P ϭ 0.30) in older subjects. Conversely, appendicular skeletal muscle mass explained a greater portion of the variance in older subjects for both T es (older: 28%, P Ͻ 0.01; young: 8%, not significant) and It (older: 46%, P Ͻ 0.01; young: 17%, P Ͻ 0.01). The Tes residual variance was considerably larger in older subjects (59 -72% vs. 14 -42% in young subjects), possibly due to varying rates of physiological aging. These results suggest that the relative influence of individual characteristics changes with aging. core temperature; tissue insulation; body composition; aging EPIDEMIOLOGICAL EVIDENCE SUGGESTS that older individuals are more susceptible to hypothermia than young individuals, with Ͼ50% of deaths due to hypothermia occurring in those aged Ͼ65 yr, an age cohort comprising only ϳ12% of the US population (8). Cross-sectional studies confirm that aged individuals have a relative inability to maintain core temperature

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“…However, there are reports that obese women have a lower abdominal skin temperature when exposed, lightly dressed, to E211 OBESITY DOES NOT INSULATE subthermoneutral temperatures (20 -25°C) (12,30,46,47). The connotation that fat insulates in humans seems experimentally to be based primarily on this type of observation.…”

Section: Does Obesity Insulate Humans?mentioning

confidence: 99%

No insulating effect of obesity

Fischer

Csikasz

Essen

et al. 2016

American Journal of Physiology-Endocrinology and Metabolism

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The development of obesity may be aggravated if obesity itself insulates against heat loss and thus diminishes the amount of food burnt for body temperature control. This would be particularly important under normal laboratory conditions where mice experience a chronic cold stress (at Ϸ20°C). We used Scholander plots (energy expenditure plotted against ambient temperature) to examine the insulation (thermal conductance) of mice, defined as the inverse of the slope of the Scholander curve at subthermoneutral temperatures. We verified the method by demonstrating that shaved mice possessed only half the insulation of nonshaved mice. We examined a series of obesity models [mice fed high-fat diets and kept at different temperatures, classical diet-induced obese mice, ob/ob mice, and obesity-prone (C57BL/6) vs. obesityresistant (129S) mice]. We found that neither acclimation temperature nor any kind or degree of obesity affected the thermal insulation of the mice when analyzed at the whole mouse level or as energy expenditure per lean weight. Calculation per body weight erroneously implied increased insulation in obese mice. We conclude that, in contrast to what would be expected, obesity of any kind does not increase thermal insulation in mice, and therefore, it does not in itself aggravate the development of obesity. It may be discussed as to what degree of effect excess adipose tissue has on insulation in humans and especially whether significant metabolic effects are associated with insulation in humans. obesity; insulation; ob/ob DESPITE THE PRESENT INTEREST IN METABOLISM in connection with the global obesity epidemic, there is little knowledge concerning the extent to which obesity as such affects metabolism. There is widespread interest in issues such as the release of adipokines from adipose tissue depots, but many basic issues, such as the ability of adipose tissue to affect metabolism physically, have been little examined. One of these issues is the question of the ability of adipose tissue to function as a thermal insulation barrier, decreasing the heat loss from the organism and in this way decreasing the amount of energy needed to keep the organism warm, thereby increasing the amount of excess energy prone to storage in the form of (additional) fat.Whether an insulating effect of obesity exists is of significance both for humans and for animal models of obesity. However, with regard to experimental animals, the issue of insulation is of further interest. This is because most metabolic experiments are conducted with mice kept under conditions (standard laboratory conditions of Ϸ21°C) that are principally cold for the mouse (10,19,27,37,38,42,44) and thus where a high proportion of total metabolism (nearly half) is devoted to counteracting the resulting heat loss. This is a condition very different from that which is relevant for the metabolic physiology of most humans (living in a thermoneutral environment). Thus, under the current experimental conditions for mice, an insulating effect of increasing obesit...

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Increased thermal body insulation: relationship to the development of obesity.

Cited by 57 publications

References 0 publications

Sweating Is Greater in NCAA Football Linemen Independently of Heat Production

Sweating Is Greater in NCAA Football Linemen Independently of Heat Production

Responses to mild cold stress are predicted by different individual characteristics in young and older subjects

No insulating effect of obesity

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