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PubMedDate not supplied

Body composition analysis by dual energy x-ray absorptiometry and anthropometry in adults with childhood-onset growth hormone (GH) deficiency before and after six months of recombinant GH therapy.

Measurements of total body fat (BF) and fat free mass (FFM) obtained by anthropometry, using the Durnin and Womersley (DW) equations, and by total body dual energy x-ray absorptiometry (DXA) were compared in 8 adults with childhood-onset GH deficiency (GHD) and in 9 healthy subjects. The sensitivity of these two methods in detecting the changes in body composition produced by six months of GH therapy in patients with GHD was also compared. Anthropometric determination of percent BF was calculated from the sum of biceps, triceps, subscapular and suprailiac skinfolds, using the appropriate DW and Siri equations for body density and percent fat estimation. FFM was calculated by subtracting BF from body mass (BM). BF and FFM were also determined by DXA (QDR 1000/W, Hologic Inc). The data obtained from the GHD patients were compared with those recorded in a control group of healthy males, matched for sex, age and physical activity. Body composition obtained by anthropometry: before GH treatment, significant differences existed between patients and controls in terms of BM (mean +/- SD: 45.8 +/- 10.0 vs 71.7 +/- 6.6 kg), percent BF (21.0 +/- 3.2 vs 17.1 +/- 3.7%) and FFM (36.0 +/- 6.5 vs 59.3 +/- 3.7 kg), while body mass index (BMI, kg/m2) values were similar in the two groups. Six months of GH therapy did not change BM and BMI, but caused a significant reduction of percent BF (from 21.0 +/- 3.2 to 18.6 +/- 4.0%) and a rise of FFM (from 36.0 +/- 6.5 to 38.0 +/- 6.7 kg). After treatment, no significant differences were found between percent BF values of patients and controls. Body composition obtained by DXA: BF (22.0 +/- 3.9%) and FFM (37.2 +/- 8.0 kg) of patients significantly differed from those of controls (16.8 +/- 3.7% and 59.8 +/- 3.7 kg) before treatment; after GH treatment, percent BF values (17.7 +/- 4.9%) of patients were similar to those of controls. Anthropometry vs DXA: high correlation (p < 0.001-0.0001, R2 = 0.784-0.988) was found between the percent BF and FFM determined by anthropometry and by DXA for both patients, before and after treatment, and controls. It is noteworthy that, for both BF and FFM, most values were evenly distributed along the identity line, showing no systematic overestimation or underestimation by anthropometry. The relation between DXA and anthropometry was maintained even after GH treatment. These results indicate that body fat and FFM assessment by anthropometry are comparable to those by DXA. GH-induced changes in body composition in hypopituitary adults are detected with the same level of accuracy by the two techniques. The reliability, practicality and low cost of anthropometry favour its use for the assessment of body composition even in GHD patients.

Absorptiometry, Photon↗

PubMed2002

Leg muscle mass and composition in relation to lower extremity performance in men and women aged 70 to 79: the health, aging and body composition study.

OBJECTIVES: The loss of muscle mass with aging, or sarcopenia, is hypothesized to be associated with the deterioration of physical function. Our aim was to determine whether low leg muscle mass and greater fat infiltration in the muscle were associated with poor lower extremity performance (LEP). DESIGN: A cross-sectional study, using baseline data of the Health, Aging and Body Composition study (1997/98). SETTING: Medicare beneficiaries residing in ZIP codes from the metropolitan areas surrounding Pittsburgh, Pennsylvania, and Memphis, Tennessee. PARTICIPANTS: Three thousand seventy-five well-functioning black and white men and women aged 70 to 79. MEASUREMENTS: Two timed tests (6-meter walk and repeated chair stands) were used to measure LEP. Muscle cross-sectional area and muscle tissue attenuation (indicative of fat infiltration) were obtained from computed tomography scans at the midthigh. Body fat was assessed using dual-energy x-ray absorptiometry. RESULTS: Blacks had greater muscle mass and poorer LEP than whites. Black women had greater fat infiltration into the muscle than white women. After adjustment for clinic site, age, height, and total body fat, smaller muscle area was associated with poorer LEP in all four race-gender groups. (Regression coefficients, expressed per standard deviation (+/-55 cm2) of muscle area, were 0.658 and 0.519 in white and black men and 0.547 and 0.435 in white and black women, respectively, P <.01.) In addition, reduced muscle attenuation-indicative of greater fat infiltration into the muscle-was associated with poorer LEP, independent of total body fat and muscle area. (Regression coefficients per standard deviation (= 7 Hounsfield Units) of muscle attenuation were 0.292 and 0.224 in white and black men, and 0.193 and 0.159 in white and black women, respectively, P <.05). The most important body composition components related to LEP were muscle area in men and total body fat in women. Results were similar after additional adjustment for lifestyle factors and health status. No interactions between race and muscle area (P>.7) or between race and muscle attenuation (P>.2) were observed. CONCLUSION: Smaller midthigh muscle area and greater fat infiltration in the muscle are associated with poorer LEP in well-functioning older men and women.

Absorptiometry, Photon↗

PubMed2001

Use of dual energy x-ray absorptiometry for noninvasive body composition measurements in clinically normal dogs.

OBJECTIVE: To determine quantitative values for components of body composition in clinically normal dogs of various breeds by use of dual energy x-ray absorptiometry (DEXA) and validate the precision and accuracy of DEXA technology in dogs. ANIMALS: 103 clinically normal sexually intact adult dogs. PROCEDURE: In a cross-sectional study, Beagles, Pembroke Welsh Corgis, Golden Retrievers, Great Danes, Pointers, Rottweilers, and nonpurebred dogs received total body DEXA scans. For the validation portion of the study, the results of DEXA scans of 6 dogs were compared with values obtained by chemical analyses of tissues from euthanatized dogs to determine the accuracy of this modality in dogs. RESULTS: Results (coefficient of variation) of the precision tests ranged from 0.10% for lean tissue to 5.19% for fat tissue, whereas accuracy tests revealed a difference between percentage bone mineral content and ash values. Body composition differed by sex, such as higher lean tissue and bone mineral content in males within some breeds, and among breeds. Regardless of body size or weight, the percentage of body weight that was bone mineral ranged from 3 to 4.0% [corrected]. CONCLUSIONS AND CLINICAL RELEVANCE: Results of this cross-sectional study provide valuable body composition data for clinically normal adult dogs, which may have research and clinical applications.

Absorptiometry, Photon↗

PubMedDate not supplied

Relationships between plasma leptin levels and body composition parameters measured by different methods in postmenopausal women.

The aim of this study was to determine the effects of body composition measured by different methods with different measurement errors on fasting plasma leptin level in normal body mass and obese postmenopausal women. It was hypothesized that the relationship between plasma leptin concentration and body fat is higher using more sophisticated laboratory methods (dual energy X-ray absorptiometry, DXA) in comparison with field methods (bioelectrical impedance analysis, BIA, or skinfold thickness) for body fat measurement because of the greater precision of DXA measurements. Thirty-five postmenopausal (55-83 years of age) healthy Estonian women were divided into two groups: BMI < 27 kg/m(2) as non obese (n = 18) and BMI> 27 kg/m(2) as obese (n = 17). Body composition was determined using DXA (total body, arms, legs, and trunk fat percent, fat mass, and LBM) and BIA methods. Body fat percent was significantly higher using the DXA method. Subcutaneous adipose tissue distribution was determined by measuring nine skinfold thicknesses. Body fat distribution was defined as the ratio of waist-to-hip (WHR) and waist-to-thigh (WTR) circumferences. Leptin was determined by means of radioimmunoassays. Leptin concentration was not significantly different between groups (19.0 +/- 13.3 and 21.5 +/- 21.5 ng/ml in non obese and obese groups, respectively). Body fat percent and fat weight measured by DXA or BIA methods and all measured skinfold thickness values, except biceps and abdominal, were higher in obese women. Body height did not correlate significantly with leptin concentrations. The relationships between leptin concentration were highest with body weight (r = 0.67) and BMI (r = 0.73) values in the obese group. All measured body fat parameters using DXA or BIA methods correlated significantly with plasma leptin concentration in the obese group. LBM did not influence the leptin concentration in postmenopausal women. Stepwise multiple regression analysis indicated that the body fat percent measured using the DXA method was highly related to plasma leptin concentration in the obese group (63.2%; R(2) x 100). When absolute fat mass parameters were considered, leptin concentration was related to the mass of arms fat tissue in the obese group of women (62.3%). Body fat percent measured by BIA was highly related to plasma leptin concentration in the obese group (63.3%). Only biceps skinfold thickness was related to leptin concentration (22.5% and 58.9%, in the nonobese and obese groups, respectively) from the nine measured skinfold thicknesses. WHR and WTR did not reflect leptin concentration in different groups of postmenopausal women. It was concluded that different methods of body composition estimation generate different correlations with plasma leptin concentration. Body fat percent and especially fat mass measured by DXA are the main predictors relating to plasma leptin concentration in obese, but not in nonobese, postmenopausal women. In addition, fat mass in arms measured by DXA and biceps skinfold thickness were also highly related to leptin concentration.

Absorptiometry, Photon↗

PubMed2006

Body composition and fatness patterns in Prader-Willi syndrome: comparison with simple obesity.

OBJECTIVE: To characterize the body composition of Prader-Willi syndrome (PWS) subjects and compare with simple obesity. RESEARCH METHODS AND PROCEDURES: Seventy-two individuals (27 PWS deletion, 21 PWS uniparental disomy, and 24 obese controls) 10 to 49 years old were studied with the use of DXA. Body composition measures were obtained, and regional fat and lean mass patterns were characterized. Significant differences were assessed with Student's t test and ANOVA adjusting for age, gender, and BMI. RESULTS: Significant differences between the PWS and obese groups were found for lean measures of the arms, legs, and trunk. Total lean mass was significantly lower in PWS than in obese subjects for arms, trunk, and especially legs. Furthermore, two body regions (legs and trunk) showed significant differences for fat and lean measures between PWS and obese males. However, significant differences between PWS and obese females for these measures were found only for the legs. No significant differences were identified between PWS deletion and uniparental disomy subjects. DISCUSSION: Our results demonstrate that PWS individuals do, in fact, have an unusual body composition and fatness patterns, characterized by reduced lean tissue and increased adiposity, with PWS males contributing most with fat patterns more similar to females.

Absorptiometry, Photon↗

PubMed2005

Changes in body composition in lactating adolescent mothers.

We assessed changes in body composition in lactating adolescent mothers living under unfavorable socioeconomic and sanitary conditions. A total of 17 healthy primiparous adolescents under 17 years of age attending the Maternity Hospital of the city of La Plata, Argentina, were followed at 4 time points (15 days and 3, 6 and 12 months postpartum) to assess, a) dietary intake, b) practice of physical activity, c) nutritional condition (weight, height, body mass index [BMI] according to age, and body composition by the sum of skinfold measurements), d) characteristics of lactation, and e) growth parameters of the child. The mean age of adolescents was 15.06 +/- 0.66 years (mean menarchal age, 11.59 +/- 0.80 years). All adolescents breastfed up to 12 months postpartum, and maternal milk covered above 80% the baby intake (mean 7.06 +/- 2.54 breast feeds/day). While the daily intake of nutrients by adolescent mothers was constant up to 6 months postpartum, there was a modest decrease in that of proteins, carbohydrates and lipids 15 days and 12 months postpartum. The decrease in energetic intake during the same period was significant (p < 0.05). The practice of physical activity was classified as moderate during the follow-up period. Whereas mean basal percent of fat body mass (FBM) was 29.85 +/- 2.87, and decreased significantly at 6 (27.2% +/- 3.9%; p = 0.02) and 12 (26.1% +/- 3.9%; p = 0.002) months postpartum, changes in lean body mass (LBM) were not significant. In conclusion, lactating adolescents maintained LBM, whereas weight, FBM and BMI decreased markedly from 3 months postpartum.

Adolescent↗

PubMed1996

Body weight and body composition during sixty days of isolation.

The aim of this study was to find the mechanisms leading to the weight changes that have frequently been observed during isolation and in spaceflight. Isolation studies with small groups impose limitations on the measurements that can be performed to simple, noninvasive methods. In this study the simple parameters of body weight and body composition, along with sodium and potassium excretion, were determined in three males and one female subject before, during and after 60 days of isolation. Our assumption was that application of these simple methods might provide valuable information, when measurements are done on a daily basis and when the pre- and post-isolation periods are taken into account. Three subjects gained weight before isolation, while one lost weight. All four subjects gradually lost weight during isolation, 1-4% of their weight on the first day of isolation. During the first post-isolation week weight remained stable. During isolation one subject lost body fat, whereas another lost body water and lean body mass, but gained body fat. The urinary electrolyte excretion pattern reflected the changes in body composition: sodium loss coincided with a decrease of total body water, and potassium loss with a decrease of lean body mass. The Bioelectrical Impedance Analysis method, used in defining changes in body composition, provided data in good agreement with those obtained with the double-labeled water method. The results reported here are in agreement with observations reported by other investigators with respect to the body weight changes and the body composition. However, it is still not understood why some subjects lose fat and others gain fat under identical conditions. Psychological factors may be involved in these individual differences. Two further points have become clear from these studies: (1) the pre- and post-isolation periods should be taken into account, (2) urinary electrolyte excretion must be seen in the context of changes in body composition, not only in the context of kidney function.

Adult↗

PubMed1986

Influence of plane of nutrition on body composition, organ size and energy utilization of Sprague-Dawley rats.

Male (61) and female (53) Sprague-Dawley rats (31 d of age, 85 g) were used to evaluate the influence of plane of nutrition on body composition, internal organ size and energy utilization. Six male and nine female rats were sacrificed initially. The remaining animals were randomly assigned, within sex, and fed to gain either 105 g (H) or 40 g (M) or lose 25 g (L) during a 21-d period. Nine rats each from the H and M groups and six from the L group were then sacrificed. The remaining rats from the H (27) and M (27) groups were fed to gain at the H, M or L rate and rats from the L (12) group were fed to gain at the H or M level during a second 21-d period. All rats were sacrificed at the end of the second period. Body composition and weights of internal organs were determined and relationships between energy intake and energy gain were evaluated. Results indicated that at the end of period 2, body composition at equal age and body weight was influenced by nutritional treatment. At equal body weight, body protein weights were lower (P less than 0.05) and body fat, liver and gut weights higher (P less than 0.05) for rats on higher planes of nutrition. Feed required for maintenance of rats during period 2 tended to be lower and efficiencies of gain tended to be higher for rats fed the low level than for those fed the high level during period 1. Rats fed the medium level during period 1 had similar maintenance requirements but higher efficiencies of gain during period 2 than rats fed the high level during period 1. These results suggest that previous nutrition influenced energy utilization through adaptation of high energy expending internal organs as well as through alterations in body composition and composition of body weight gain.

Animal Nutritional Physiological Phenomena↗

PubMed1991

Effects of hydration and dehydration on body composition analysis: a comparative study of bioelectric impedance analysis and hydrodensitometry.

Since 1983, bioelectric impedance has been researched with respect to its validity and reliability in the determination of body composition. It continues to be compared to hydrostatic weighing, the anthropometric "gold standard". This study was designed to investigate the relationship between bioelectric impedance analysis (BIA) and hydrodensitometry (HW) under three conditions: control, hydration and dehydration. Caucasian males (aged 18-44 years) served as subjects (n = 10). Body composition was determined by BIA and HW before intervention, 30 minutes post-hydration, and following a combination of exercise and sitting in a steam room to decrease body weight by two to four percent (mean = 2.81%). Statistical treatment by two-way analysis of variance for repeated measures revealed that although there were no significant differences between the two techniques of body composition determination under any of the three conditions, there was a statistically significant decrease in percent body fat determined in the dehydrated state as compared to the control and hydrated conditions. Recommendations include the determination of hydration state prior to engaging in body composition analysis by either method.

Adipose Tissue↗

PubMed1990

Body composition studies in premenopausal healthy women.

Body composition studies of healthy premenopausal women were performed using dual photon absorptiometry and the results compared with fat estimates obtained from skinfold measurements, body mass index, and bioelectrical impedance. Total body bone mineral did not decline with age nor did the fraction of lean body mass occupied by the skeleton, which ranged from 4-10%. DPA values for fat were significantly higher than those obtained by other techniques, in part because of calibration but also because of apparent inadequate correction for the fraction of lean body mass occupied by bone in the assumptions made for the other techniques.

Absorptiometry, Photon↗

PubMedDate not supplied

Assessment of body composition by skinfold anthropometry and bioelectrical impedance technique: a comparative study.

Both skinfold anthropometry and bioelectrical impedance are indirect, simple bedside methods to assess body composition. It is not clear, however, whether the results of these methods are comparable. In this study, body composition was determined in 449 subjects by skinfold anthropometry and by bioelectrical impedance. Percentage of body fat ranged from 8.0% to 47.5% with the skinfold technique and from 0.6% to 78.5% with bioelectrical impedance. Linear regression analysis showed a significant positive correlation (r = .84; p < .0001) between the results of both techniques. However, plot analysis showed that, in comparison with bioelectrical impedance, skinfold measurements overestimate fat mass in the lower weight range and underestimate it in obese subjects. We conclude that the results of skinfold anthropometry and bioelectrical impedance are not comparable, especially in the extreme ranges of body fat. At the present time, other, more rigorous techniques are necessary to assess body composition accurately, in the extreme ranges of body fat in particular.

Adolescent↗

PubMed2005

Effect of growth hormone therapy and puberty on bone and body composition in children with idiopathic short stature and growth hormone deficiency.

The state of bone health and the effect of growth hormone (GH) therapy on bone and body composition in children with idiopathic short stature (ISS) are largely unknown. A direct role of GH deficiency (GHD) on bone density is controversial. Using dual-energy X-ray absorptiometry, this study measured total body bone mineral content (TB BMC), body composition, and volumetric bone mineral density (vBMD) at the lumbar spine (LS) and femoral neck (FN) in 77 children (aged 3-17 years) with ISS (n = 57) and GHD (n = 20). Fifty-five children (GHD = 13) receiving GH were followed over 24 months including measurement of bone turnover. At diagnosis, size-corrected TB BMC SDS was greater (P <or= 0.002) and LSvBMD SDS lower (P < 0.03) than zero in both prepubertal ISS and GHD subjects, but FNvBMD SDS was reduced only in the GHD group (P < 0.05). The muscle-bone relation, as assessed by the BMC/lean mass (LTM) ratio SDS was not different between groups. During GH therapy, prepubertal GHD children gained more height (1.58 [0.9] SDS) and LTM (0.87 [0.63] SDS) compared to prepubertal ISS children (0.75 [0.27] and 0.17 [0.25] SDS, respectively). Percent body fat decreased in GHD (-5.94% [4.29]) but not in ISS children. Total body BMC accrual was less than predicted in all groups accompanied by an increase in bone turnover. Puberty led to the greatest absolute, but not relative, increments in weight, LTM, BMI, bone mass, and LSvBMD. Our results show that children with ISS and GHD differ in their response to GH therapy in anthropometry, body composition, and bone measures. Despite low vBMD values at diagnosis in both prepubertal groups, size-corrected regional or TB bone data were generally within the normal range and did not increase during GH therapy in GHD or ISS children. Growth hormone had great effects on the growth plate and body composition with subsequent gains in height, LTM, bone turnover, and bone mass accrual, but no benefit for volumetric bone density over 2 years.

Absorptiometry, Photon↗

PubMed1998

Body weight, body composition, and energy intake changes in breastfeeding mothers.

Body weight, body composition, and energy intake changes are described for 13 breastfeeding mothers followed for 18-24 months after delivery. Body weight was assessed at 1-6, 9, 12, 18, 24 months postpartum and 1 month after infant weaning, and energy intake was assessed at 2-6, 9, 12, 18, 24 months postpartum and 1 month after infant weaning. Compared to prepregnancy weight, participants were an average of 4.0 +/- 6.6 kg heavier 18 months postpartum (p < 0.05). The mean rate of weight loss from 1 month postpartum until termination of lactation was 0.32 +/- 0.27 kg/month. Eight of the 12 women gained weight after weaning their infant. Percent body fat assessed by underwater weighing declined from 34.6 +/- 2.8% at 1 month postpartum to 31.4 +/- 4.8% at 1 month after infant weaning (p < 0.05). Further research is needed to study the factors which affect weight loss postpartum, and how weight gain after weaning can be prevented.

Adult↗

PubMed1983

[Effect of lactation on the weight and body composition of wet nurses].

In order to assess the impact of lactation on the nutritional status and body composition of mothers, 134 women were followed up during a period of six months (95 were exclusively breast-feeding and 39 were bottle-feeding their babies). Their weight was measured at monthly intervals, and mid-arm circumference, skinfold thickness and food intake were determined at two and six months, respectively, as well as food intake by the 24-hour recall method. Both groups evidenced similar non significant and slight changes in weight and body composition. Only 10% of mothers showed weight losses above 4 kg; weight loss was significantly higher in overweight and obese women as compared to underweight and normal mothers. Both arm circumference and total fat (sum of skinfolds thickness) followed the same trend. Dietary intake revealed to be deficient in calories, protein, calcium, iron and vitamin A when compared to the FAO/WHO standards. Given the excellent growth curves of the children as well as the minimal changes observed in maternal nutrition and body composition, it may be assumed that the current recommended dietary allowances (FAO/WHO) are overestimated for a population of the type studied.

Body Composition↗

PubMed1980

Body composition in cachexia resulting from malignant and non-malignant diseases.

The body composition of 23 patients with cachexia resulting from malignant or benign inflammatory disease was studied. Skinfold thickness and radioisotope tracer measurements enabled us to estimate total body fat, lean body mass, the ratio of fat loss to lean body loss, erythrocyte and plasma volumes, total body water, extra-, and intracellular water volumes, total body potassium, and intracellular potassium concentration. The total body fat and lean body mass information suggests that the body composition in cancerous cachexia differs from that in cachexia caused by benign inflammatory disease, in that lean tissue appears to be better conserved in the former. The radioactive tracer studies showed that the cachectic patients were anemic, potassium-deficient, and overhydrated; however, fluid partitioning into extra- and intracellular compartments was normal.

Adolescent↗

PubMed1995

Body composition assessed by bioelectrical impedance analysis (BIA) in patients with Graves' disease before and after treatment.

Body composition was assessed by bioelectrical impedance analysis (BIA) in 11 female patients with Graves' disease and in 49 age-matched healthy Japanese women. Patients with Graves' disease were examined in the hyperthyroid state before treatment and in the stable euthyroid state after treatment with antihyroid drugs for 6 to 18 months. Body weight (BW), percent body fat (BF/BW), percent lean body mass (LBM/BW) and percent total body water (TBW/BW) were not statistically different between hyperthyroid Graves' patients and healthy subjects. Percent body cell mass (BCM/BW) was much lower in hyperthyroid Graves' patients than in healthy subjects (mean +/- SEM; 33.9 +/- 2.4% vs. 41.5 +/- 0.5%, P < 0.001). Percent ratio of extracellular water to total body water (ECW/TBW) was much greater in hyperthyroid Graves' patients than in healthy subjects (53.9 +/- 3.0% vs. 41.8 +/- 0.5%, P < 0.001). These abnormal ratios, BCM/BW and ECW/TBW, were normalized after treatment. Serum free T4 levels showed a positive correlation with ECW/TBW (r = 0.779) and a reverse correlation with BCM/BW (r = -0.760) in all of the patients with Graves' disease examined. These findings indicate that body composition is affected by thyroid hormones and that body composition in hyperthyroid Graves' disease is characterized by decreased BCM associated with increased ECW.

Adolescent↗

PubMed1999

Use of the leg-to-leg bioelectrical impedance method in assessing body-composition change in obese women.

BACKGROUND: There is little information on whether bioelectrical impedance analysis (BIA) accurately predicts changes in body composition associated with energy restriction, exercise, or both. OBJECTIVE: We had 2 objectives: to determine the validity of the leg-to-leg BIA system in 1) estimating body composition in obese and nonobese women, with a cross-sectional design, and 2) assessing changes in body composition in obese women in response to 12 wk of energy restriction, exercise training, or both. DESIGN: Subjects were 98 moderately obese women (43.2 +/- 0.6% body fat, 45.0 +/- 1.1 y of age) and 27 nonobese control subjects (24.0 +/- 1.5% body fat, 43.5 +/- 2.5 y of age). Obese subjects were randomly divided into 1 of 4 groups, with fat-free mass, fat mass, and percentage body fat estimated with BIA and underwater weighing before and after 12 wk of intervention. The 4 groups were diet only (4.19-5.44 MJ/d), exercise only (five, 45-min sessions/wk at 78.5 +/- 0.5% of maximum heart rate), both exercise and diet, and control (no diet or exercise). RESULTS: No significant difference was found between underwater weighing and BIA in estimating the fat-free mass of the obese and nonobese women (all subjects combined, r = 0.78, P < 0.001, SEE = 3.7 kg) or in estimating decreases in fat mass during 12 wk of energy restriction, exercise, or both in obese subjects (F[3.85] = 1.45, P = 0.233). CONCLUSIONS: The leg-to-leg BIA system accurately assessed fat-free mass in obese and nonobese women, and changes in fat mass with diet alone or when combined with exercise.

Adipose Tissue↗

PubMed1984

Effect of physical fitness and body composition on sleep and sleep-related hormone concentrations.

The study assessed the effect of physical fitness and body composition on sleep and the nighttime secretion of the hormones, human growth hormone (hGH), prolactin, and cortisol. Two groups of 17 subjects, one of fit athletes and the other of unfit nonathletes, were selected so that the groups were matched for weight, height, lean body mass (LBM), and fat levels. Subjects slept in a sleep laboratory for 3 nonconsecutive nights: 1 adaptation night and 2 experimental nights. On 1 experimental night blood samples were collected; on the other, baseline sleep was assessed and the catheter was not inserted. Weight and height were measured and LBM assessed by 24 h urinary creatinine. The effect of physical fitness was tested by a comparison of the two groups; body composition was assessed by correlation analyses. Physical fitness did not have a significant effect on either sleep or hormone levels, although in the latter case the results were marginal. In contrast, body composition was related to both sleep and hGH. Percentage LBM was negatively correlated with slow-wave sleep and positively correlated with hGH levels. These results were significant for all subjects combined and for the fit group, although not the unfit group alone.

Adipose Tissue↗