Temperature regulation during rest and exercise in the cold in premenarcheal and menarcheal girls

2004 ◽  
Vol 96 (4) ◽  
pp. 1393-1398 ◽  
Author(s):  
Panagiota Klentrou ◽  
Melora Cunliffe ◽  
Jill Slack ◽  
Boguslaw Wilk ◽  
Oded Bar-Or ◽  
...  
Keyword(s):  
Core Temperature ◽  
Body Fat ◽  
Heat Production ◽  
Temperature Regulation ◽  
Maximal Oxygen Consumption ◽  
Rest Period ◽  
Cold Test ◽  
Percent Body Fat ◽  
Menstrual Phase

Temperature regulation during exercise in the cold was examined in 13 adolescent female individuals, aged 13-18 yr. Six girls with established menstrual cycles comprised the eumenorrheic menarcheal (EM) group, and seven nonmenstruating girls comprised the premenarcheal (PM) group. During the first visit, maximal oxygen consumption (V̇o2 max), height, weight, and percent body fat were measured. The second visit included a determination of metabolic rate in thermoneutrality (21°C), consisting of a 10-min rest period and 20 min of cycling (30% of V̇o2 max), and a cold test (5°C, 40% humidity, <0.3 m/s air velocity) involving a 20-min rest period and 40 min of cycling (30% of V̇o2 max). Subjects in the EM group were tested twice in the chamber: once during the follicular and once during the luteal phase. Heat production per kilogram in thermoneutrality and in the cold was significantly ( P < 0.05) higher in the PM compared with the EM girls. However, the PM girls had a significantly ( P < 0.05) lower core temperature in the cold than the EM group. PM girls also had a significantly higher body surface area-to-mass ratio compared with the EM girls. Although percent body fat between groups was not significantly different, within the PM group percent body fat explained 79% ( P < 0.01) of the variance in the decrease of core temperature. There were no menstrual phase-related differences in temperature regulation in either the thermoneutral or cold environment. In conclusion, menstrual phase does not influence temperature regulation in female individuals during adolescence. EM girls had lower metabolic heat production but maintained their core temperature more effectively in the cold than did the PM girls. This thermoregulatory difference between PM and EM girls is mainly a function of geometric differences with maturation-related peripheral vasoconstrictive differences maybe limiting the effectiveness of the mechanism of increased heat storage in younger female individuals.

Interaction of central and peripheral factors in physiological temperature regulation

1961 ◽  
Vol 200 (3) ◽  
pp. 572-580 ◽  
Author(s):  
M. M. Fusco ◽  
J. D. Hardy ◽  
H. T. Hammel
Keyword(s):  
Heat Loss ◽  
Core Temperature ◽  
Heat Production ◽  
Temperature Regulation ◽  
Physiological Temperature ◽  
Warm Environment ◽  
Quantitative Estimates ◽  
Cool Environment ◽  
Localized Heating ◽  
Environmental Temperatures

To evaluate the relative importance of central and peripheral factors in physiological temperature regulation, calorimetric measurements of thermal and metabolic responses in the unanesthetized dog to localized heating of the supraoptic and preoptic regions were made at various environmental temperatures. At all temperatures, heating the hypothalamus caused an imbalance in the over-all heat exchange, and lowered core temperature by 0.8°–1.0°C. In a neutral environment, this was effected by a 30–40% depression of the resting rate of heat production. In a cool environment, heating inhibited shivering so that heat production, relative to heat loss, was low. In a warm environment, vigorous panting and vasodilatation were elicited, thereby increasing heat loss. On cessation of heating, shivering occurred in response to the lowered core temperature, but differed in intensity depending upon the peripheral thermal drive. Reapplication of heating suppressed shivering in all cases. From these data some quantitative estimates were made of the sensitivity of the hypothalamic thermoregulatory ‘centers’, and of the interaction and relative contributions of central and peripheral control.

scholarly journals Determination of Percent Body Fat by the Newly Developed Sulfur Hexafluoride Dilution Method and Air Displacement Plethysmography.

1998 ◽  
Vol 44 (4) ◽  
pp. 561-568 ◽  
Author(s):  
Hiroko IWAOKA ◽  
Tetsuji YOKOYAMA ◽  
Takeo NAKAYAMA ◽  
Yasuhiro MATSUMURA ◽  
Yutaka YOSHITAKE ◽  
...  
Keyword(s):  
Body Fat ◽  
Sulfur Hexafluoride ◽  
Percent Body Fat ◽  
Dilution Method ◽  
Air Displacement Plethysmography

scholarly journals Twenty-Four Hour Growth Hormone and Leptin Secretion in Active Postpubertal Adolescent Girls: Impact of Fitness, Fatness, and Age at Menarche

2006 ◽  
Vol 91 (10) ◽  
pp. 3935-3940 ◽  
Author(s):  
J. Z. Kasa-Vubu ◽  
W. Ye ◽  
K. T. Borer ◽  
A. Rosenthal ◽  
T. Meckmongkol
Keyword(s):  
Physical Activity ◽  
Body Composition ◽  
Body Fat ◽  
Adolescent Girls ◽  
Repeated Measures ◽  
Maximal Oxygen Consumption ◽  
Percent Body Fat ◽  
Age At Menarche ◽  
Entire Group ◽  
Gh Secretion

Abstract Context: GH is strongly related to body composition, physical activity, and pubertal progression. Adolescent girls decrease physical activity during puberty, whereas their weight increases. Because leptin is a good index of energy balance in active young women, we hypothesized that leptin is related to GH secretion in this population while taking into account fitness, fatness, and age at menarche. Methods: We measured body composition and maximal oxygen consumption (VO2max) in 37 postpubertal adolescent girls aged 16–21 yr. GH was sampled every 10 min and leptin hourly for 24 h. We first analyzed 6-h time blocks by repeated measures for GH and leptin, with body mass index (BMI), percent body fat, and VO2max as covariates for the entire group and a lean subgroup. The deconvolution method was used to characterize GH pulsatility from individual time points. Results: GH varied through the day (P &lt; 0.0001), with the highest concentrations overnight. BMI, percent body fat, and VO2max were related to GH concentrations in the entire group, whereas leptin predicted GH in the entire group as well as the lean subgroup of girls. Higher leptin was related to lower GH concentrations (P = 0.011), regardless of time. A log leptin level increase by 1 unit decreased GH by 27%. Pulsatility characteristics showed a 1-yr increase of age at menarche increasing total GH input by 20% (P = 0.0035) independently from BMI. Conclusion: In postpubertal adolescent girls, leptin is related to GH concentration across the lean to overweight BMI spectrum. GH pulsatile secretion was greater in girls with later age at menarche.

Effects of 2-G exposure on temperature regulation, circadian rhythms, and adiposity in UCP2/3 transgenic mice

2000 ◽  
Vol 89 (4) ◽  
pp. 1491-1498 ◽  
Author(s):  
Patrick M. Fuller ◽  
Craig H. Warden ◽  
Sean J. Barry ◽  
Charles A. Fuller
Keyword(s):  
Body Composition ◽  
Energy Balance ◽  
Body Temperature ◽  
Energy Expenditure ◽  
Transgenic Mice ◽  
Body Fat ◽  
Temperature Regulation ◽  
Percent Body Fat ◽  
Wild Type ◽  
Fat Pads

Altered ambient force environments affect energy expenditure via changes in thermoregulation, metabolism, and body composition. Uncoupling proteins (UCPs) have been implicated as potential enhancers of energy expenditure and may participate in some of the adaptations to a hyperdynamic environment. To test this hypothesis, this study examined the homeostatic and circadian profiles of body temperature (Tb) and activity and adiposity in wild-type and UCP2/3 transgenic mice exposed to 1 and 2 G. There were no significant differences between the groups in the means, amplitudes, or phases of Tb and activity rhythms at either the 1- or 2-G level. Percent body fat was significantly lower in transgenic (5.2 ± 0.2%) relative to the wild-type mice (6.2 ± 0.1%) after 2-G exposure; mass-adjusted mesenteric and epididymal fat pads in transgenic mice were also significantly lower ( P < 0.05). The data suggest that 1) the actions of two UCPs (UCP2 and UCP3) do not contribute to an altered energy balance at 2 G, although 2) UCP2 and UCP3 do contribute to the utilization of lipids as a fuel substrate at 2 G.

A SIMPLIFIED TECHNIQDE FOR TIE DETERMINATION OF PERCENT BODY FAT IN MALE PUBLIC SAFETI PERSONNEL

1982 ◽  
Vol 14 (2) ◽  
pp. 160 ◽  
Author(s):  
Arthur V. Curtis ◽  
Charles O. Dotson ◽  
Paul O. Davis
Keyword(s):  
Body Fat ◽  
Percent Body Fat

scholarly journals High percent body fat mass predicts lower risk of cardiac events in patients with heart failure: an explanation of the obesity paradox

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Katsuhiko Ohori ◽  
Toshiyuki Yano ◽  
Satoshi Katano ◽  
Hidemichi Kouzu ◽  
Suguru Honma ◽  
...  
Keyword(s):  
Heart Failure ◽  
Body Fat ◽  
Fat Mass ◽  
Cardiac Event ◽  
Muscle Wasting ◽  
Obesity Paradox ◽  
Percent Body Fat ◽  
Body Fat Mass ◽  
Cardiac Events ◽  
Kaplan Meier

Abstract Background Although high body mass index (BMI) is a risk factor of heart failure (HF), HF patients with a higher BMI had a lower mortality rate than that in HF patients with normal or lower BMI, a phenomenon that has been termed the “obesity paradox”. However, the relationship between body composition, i.e., fat or muscle mass, and clinical outcome in HF remains unclear. Methods We retrospectively analyzed data for 198 consecutive HF patients (76 years of age; males, 49%). Patients who were admitted to our institute for diagnosis and management of HF and received a dual-energy X-ray absorptiometry scan were included regardless of left ventricular ejection fraction (LVEF) categories. Muscle wasting was defined as appendicular skeletal muscle mass index < 7.0 kg/m2 in males and < 5.4 kg/m2 in females. Increased percent body fat mass (increased FM) was defined as percent body fat > 25% in males and > 30% in females. Results The median age of the patients was 76 years (interquartile range [IQR], 67–82 years) and 49% of them were male. The median LVEF was 47% (IQR, 33–63%) and 33% of the patients had heart failure with reduced ejection fraction. Increased FM and muscle wasting were observed in 58 and 67% of the enrolled patients, respectively. During a 180-day follow-up period, 32 patients (16%) had cardiac events defined as cardiac death or readmission by worsening HF or arrhythmia. Kaplan-Meier survival curves showed that patients with increased FM had a lower cardiac event rate than did patients without increased FM (11.4% vs. 22.6%, p = 0.03). Kaplan-Meier curves of cardiac event rates did not differ between patients with and those without muscle wasting (16.5% vs. 15.4%, p = 0.93). In multivariate Cox regression analyses, increased FM was independently associated with lower cardiac event rates (hazard ratio: 0.45, 95% confidence interval: 0.22–0.93) after adjustment for age, sex, diabetes, muscle wasting, and renal function. Conclusions High percent body fat mass is associated with lower risk of short-term cardiac events in HF patients.

Discriminant Analysis of Personality and Body-Image Factors of Females Differing in Percent Body Fat

1980 ◽  
Vol 50 (2) ◽  
pp. 547-552
Author(s):  
Michael Young ◽  
T. Gilmour Reeve
Keyword(s):  
Body Image ◽  
Body Fat ◽  
Image Data ◽  
Female College Students ◽  
Percent Body Fat ◽  
Personality Factor ◽  
Personality Factor Questionnaire ◽  
Discriminant Analyses ◽  
Low Levels ◽  
Body Cathexis

The purpose of the study was to determine whether individuals with high percent body fat can be distinguished on the basis of personality and body-image from those possessing lower levels of body fat. 65 female college students were administered the 16 Personality Factor Questionnaire and the Secord and Jourard Body-cathexis Scale. Measurements of height, weight, and skin folds at the triceps and illiac crest were also taken. On the basis of percent body fat two groups of 20 females each (high and low percent body fat) were identified. From discriminant analyses one personality factor and six body-image items were identified which distinguished between groups. Reclassification of the subjects, based upon derived discriminant functions, resulted in 60.0% of the subjects being correctly reclassified from personality data and 100% of the subjects correctly reclassified from body-image data. Body-image appears to be an important factor that can distinguish between individuals possessing high and low levels of body fat.

scholarly journals Later Meal and Sleep Timing Predicts Higher Percent Body Fat

Nutrients ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 73
Author(s):  
Elizabeth A. Thomas ◽  
Adnin Zaman ◽  
Marc-Andre Cornier ◽  
Victoria A. Catenacci ◽  
Emma J. Tussey ◽  
...  
Keyword(s):  
Body Fat ◽  
Overweight And Obesity ◽  
Percent Body Fat ◽  
P Value ◽  
Activity Monitors ◽  
Food Records ◽  
Sleep Timing ◽  
Meal Timing ◽  
Increased Risk ◽  
Unit Increase

Accumulating evidence suggests that later timing of energy intake (EI) is associated with increased risk of obesity. In this study, 83 individuals with overweight and obesity underwent assessment of a 7-day period of data collection, including measures of body weight and body composition (DXA) and 24-h measures of EI (photographic food records), sleep (actigraphy), and physical activity (PA, activity monitors) for 7 days. Relationships between body mass index (BMI) and percent body fat (DXA) with meal timing, sleep, and PA were examined. For every 1 h later start of eating, there was a 1.25 (95% CI: 0.60, 1.91) unit increase in percent body fat (False Discovery Rate (FDR) adjusted p value = 0.010). For every 1 h later midpoint of the eating window, there was a 1.35 (95% CI: 0.51, 2.19) unit increase in percent body fat (FDR p value = 0.029). For every 1 h increase in the end of the sleep period, there was a 1.64 (95% CI: 0.56, 2.72) unit increase in percent body fat (FDR p value = 0.044). Later meal and sleep timing were also associated with lower PA levels. In summary, later timing of EI and sleep are associated with higher body fat and lower levels of PA in people with overweight and obesity.

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