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Biomedical subjects

G R Hunter

Publications and source records attributed to G R Hunter.

At least 73 records · Page 4Linked to original sources
PubMed1995

Reduction in intra-abdominal adipose tissue after strength training in older women.

The purpose of this study was to examine the effects of a total body strength-training program on changes in total and regional body composition, in particular intra-abdominal adipose tissue (IAAT), in older women. Fourteen healthy older women (mean age 67 +/- 1 yr) exercised 3 times/wk for 16 wk. Strength was assessed by one-repetition maximum tests, with training intensity gradually increased to approximately 67% of one repetition maximum. Body composition was measured by hydrodensitometry and regional body composition was measured by computed tomography. Strength was significantly increased in the upper (51%) and lower body (65%). There was no significant change in body weight (64.4 +/- 2.7 vs. 64.2 +/- 2.7 kg), total body fat (38.7 +/- 1.4 vs. 38.0 +/- 1.6%) or fat-free mass (39.7 +/- 1.0 vs. 40.0 +/- 0.9 kg). However, after ST, there were significant reductions in IAAT (143.9 +/- 13.3 vs. 130.0 +/- 12.4 cm2), the IAAT-to-subcutaneous adipose tissue ratio (0.48 +/- 0.04 vs. 0.44 +/- 0.04), and midthigh subcutaneous adipose tissue (141.7 +/- 11.5 vs. 133.6 +/- 10.8 cm2) and an increase in midthigh muscle (52.9 +/- 2.6 vs. 58.0 +/- 2.0 cm2) (all P < 0.05). In conclusion, significant reductions in IAAT and an increase in strength and muscle area were observed after a strength-training program in healthy older women. These changes may be important in preventing the negative health outcomes associated with the age-related increase in intra-abdominal obesity.

Abdomen↗
PubMed1995

Energy expenditure and substrate utilization in older women after strength training: 24-h calorimeter results.

The purpose of this study was to examine the effects of strength training (ST) in healthy older women on 24-h energy expenditure (EE) and its components and on 24-h substrate utilization. Thirteen women (age 67 +/- 1 yr) exercised three times per week for 16 wk in a total body ST program. EE components and substrate utilization were determined for 24 h in an indirect room calorimeter before and after training. The ST invoked a 47% increase in upper body and a 66% increase in lower body strength (P < 0.001). Body weight, percent body fat, and fat-free mass did not change significantly; however, midthigh muscle area increased (55.2 +/- 3.1 vs. 60.4 +/- 2.3 cm2; P < 0.05). There are a significant increase in resting EE (5,017 +/- 218 vs. 5,473 +/- 213 kJ/day; P < 0.05) but no significant changes in sleeping EE (4,929 +/- 180 vs. 5,067 +/- 251 kJ/day), diet-induced thermogenesis (359 +/- 25 vs. 393 +/- 33 kJ/day), activity EE (682 +/- 84 vs. 381 +/- 117 kJ/day), or 24-h EE (6,054 +/- 188 vs. 6,247 +/- 243 kJ/day). The increase in resting EE was not significant after the increase in muscle area is taken into account. The 24-h nonprotein respiratory quotient decreased (0.90 +/- 0.01 vs. 0.82 +/- 0.01; P < 0.001), revealing a significant increase in 24-h fat oxidation (42 +/- 6 vs. 81 +/- 7 g/day) and a decrease in carbohydrate oxidation (180 +/- 14 vs. 113 +/- 10 g/day; both P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1995

Metabolic predictors of obesity. Contribution of resting energy expenditure, thermic effect of food, and fuel utilization to four-year weight gain of post-obese and never-obese women.

This prospective study was designed to identify abnormalities of energy expenditure and fuel utilization which distinguish post-obese women from never-obese controls. 24 moderately obese, postmenopausal, nondiabetic women with a familial predisposition to obesity underwent assessments of body composition, fasting and postprandial energy expenditure, and fuel utilization in the obese state and after weight loss (mean 12.9 kg) to a post-obese, normal-weight state. The post-obese women were compared with 24 never-obese women of comparable age and body composition. Four years later, without intervention, body weight was reassessed in both groups. Results indicated that all parameters measured in the post-obese women were similar to the never-obese controls: mean resting energy expenditure, thermic effect of food, and fasting and postprandial substrate oxidation and insulin-glucose patterns. Four years later, post-obese women regained a mean of 10.9 kg while control subjects remained lean (mean gain 1.7 kg) (P < 0.001 between groups). Neither energy expenditure nor fuel oxidation correlated with 4-yr weight changes, whereas self-reported physical inactivity was associated with greater weight regain. The data suggest that weight gain in obesity-prone women may be due to maladaptive responses to the environment, such as physical inactivity or excess energy intake, rather than to reduced energy requirements.

Aged↗
PubMed1994

Development and validation of computed tomography derived anthropometric regression equations for estimating abdominal adipose tissue distribution.

The purpose of this study was twofold: (1) to develop multiple regression equations for predicting computed tomography (CT) derived intra-abdominal (IAF), subcutaneous (SCF), and total (TOTF= IAF+SCF) abdominal adipose tissue areas from anthropometric measures in adult white males with a large range of age (18-71 years) and percent body fat (2.0-40.6); and (2) to validate the new and existing equations that used similar Hounsfield Units (HU) for determining IAF for estimating these fat depots. One hundred fifty-one white male subjects had IAF, SCF, and TOTF determined by a single CT scan, skinfold and circumference measures taken and body density determined. Linear intra-correlations and factor analysis procedures were used to identify variables for inclusion in stepwise multiple regression solutions. IAF was estimated from age, waist circumference, the sum of mid-thigh and lower thigh circumferences, and vertical abdominal skinfold. SCF was estimated from age, umbilicus circumference, chest and suprailiac skinfolds. TOTF was estimated from age, body mass index (BMI), chest skinfold, and umbilicus circumference. R2 for IAF, SCF, and TOTF was .73, .77, and .86 respectively. The existing and the new equations were validated on an independent sub-sample of 51 subjects. The only existing equation that met validation criteria had a validation R2 = .67 for IAF. All three new equations met validation criteria with R2 validations of .75, .79, and .85 for IAF, SCF, and TOTF respectively. It is concluded that the new equations might be used as an inexpensive estimation of IAF, SCF, and TOTF in adult white males varying greatly in age and percent body fat.

Abdomen↗
PubMed1994

Intra-abdominal adipose tissue values associated with risk of possessing elevated blood lipids and blood pressure.

Central fat distribution and more recently intra-abdominal adipose tissue (IAF) have been associated with elevated cardiovascular risk factors (CRF). Despite increased interest in use of LAF for screening for CRF, interpretation of risk found in a specific IAF is difficult since regressions for estimating CRF from IAF have not been published. The purpose of this paper is to report IAF values that are likely to be associated with elevated CRF. One hundred forty-six healthy male subjects 30-71 years were evaluated for IAF and subcutaneous fat (computed tomography scan at 4th lumbar vertebra), height, body weight, % fat, various anthropometric measures, blood cholesterol (CHOL), HDL cholesterol (HDL), systolic blood pressure (SBP), and diastolic blood pressure (DBP). Receiver-Operating-Characteristic curves (ROC) were used to develop IAF cutpoints associated with elevation of at least one established CRF criteria (CHOL=200, HDL=<35, SBP=140, DBP=90). A sensitivity/(1- specificity) curve established the value of using IAF cutpoints for detecting elevated CRF. Likelihood ratios were used to identify optimal cutpoints. Two cutpoints were identified, 131 cm2 with a relatively high Lpos ratio and 71 cm2 with a relatively low Lneg. False positives associated with 131 cm2 were 14% for one or more elevated CRF. False negatives associated with 71 cm2 were 9% for one or more elevated CRF, 4% for two or more CRF, and 0% for three or more elevated CRF. This study clearly indicates that IAF above 131 cm2 is related to elevated CRF and IAF below 71 cm2 is associated with reduced cardiovascular risk.

Abdomen↗
PubMed1994

A prospective study of weight maintenance in obese subjects reduced to normal body weight without weight-loss training.

We examined the pattern of weight maintenance in 24 obese women [body mass index (BMI; in kg/m2) 27.6 +/- 0.4 who were provided foods for a balanced deficit diet until each had lost > or = 10 kg and attained normal body weight (BMI 22.9 +/- 0.4). At 1 y subjects had regained a mean of 42% of their weight loss, which increased to 87% at 4 y. At 4 y 44% of patients had regained < 75%, whereas 37% had regained > or = 100% of the weight originally lost. The amount of weight gained was markedly different from that observed in 24 pair-matched never-obese control subjects over the same length of follow-up. Because the results reported herein were obtained without teaching the subjects weight-control skills, they may be regarded as reflective of the natural history of weight maintenance in this population and may serve as a reference for various weight-intervention programs. The pattern of weight rebound observed in this study is very similar to the pattern observed in combined results from published diet and behavioral-modification programs, which raises important questions regarding the efficacy of these approaches in long-term weight maintenance.

Aged↗
PubMed1993

Changes in body composition, diet, and strength of bodybuilders during the 12 weeks prior to competition.

The purpose of this study was to monitor body composition, diet, and strength in male bodybuilders (No. 6) during the 12 weeks prior to competition. Data were collected every third week and analyzed with repeated measures ANOVA (p < 0.05). Significant decreases (p < 0.01) were found in body mass (-7.3 kg) and hydrostatically determined percent fat (-5.0%), while fat-free mass showed little change. All 7 skinfold sites were reduced significantly (p < 0.01) across the 12 weeks. Ultrasound scan revealed a significant decrease in skin thickness at the biceps (p < 0.01), but no change in biceps thickness. Circumferences decreased significantly at all sites (p < 0.05) except the chest. The greatest decreases were at the waist (-6.9 cm) and hips (-4.3 cm). Maximal isometric dead-lift force decreased significantly (p < 0.05) across time (-129 N). In comparison to off-season, both higher resistance and aerobic training volumes were found during pre-competition. Nutritional analyses showed significant reductions (p < 0.05) in total kilocalories, protein, fat, and cholesterol intakes. Vitamin and mineral intakes exceeded the RDAs. The data indicate the pre-competition practices were effective in reducing subcutaneous fat stores while maintaining muscle. Finally, the onset of the pre-competition phase resulted in strength loss.

Adult↗
PubMed1992

Lipid and insulin concentrations in obese postmenopausal women: separate effects of energy restriction and weight loss.

The separate effects of energy restriction and weight loss on serum lipids were studied in 24 postmenopausal moderately obese women before and after weight loss of greater than 10 kg to normal weight. Fasting serum triglycerides (TGs), total cholesterol (TC), high-density-lipoprotein (HDL) and low-density-lipoprotein (LDL) cholesterol, and insulin were measured at the end of four 10-d in-hospital phases, two before and two after weight loss: phase I, stable weight; phase II, 3350 kJ/d(800 kcal/d), followed by outpatient weight loss; phase III, 3350 kJ/d (800 kcal/d); and phase IV, stable weight. Diet composition and exercise were constant the entire study. Energy-restriction effect was determined by comparing average values in stable-weight phases (I and IV) with low-energy phases (II and III); weight-loss effect was determined by comparing values in obese phases (I and II) with reduced-weight phases (III and IV). Energy restriction lowered TG, TC, LDL cholesterol, the LDL-HDL cholesterol ratio, and insulin and raised HDL cholesterol (all P less than 0.05). Weight loss lowered TG, TC, LDL cholesterol, and insulin (all P less than 0.01) but did not change HDL cholesterol or the LDL-HDL cholesterol ratio. The results suggest that reduction to a weight-steady nonobese state significantly lowers TG, TC, and LDL cholesterol but does not improve HDL cholesterol or the LDL-HDL cholesterol ratio.

Aged↗
PubMed1992

Estimation of computerized tomography derived abdominal fat distribution.

Measurements of intra-abdominal fat (IAF) may be important since it is associated with numerous metabolic disorders. The relationship between computerized tomography (CT) measured fat distribution and densitometry measures was investigated in a sample of 61 male Caucasian subjects, aged 18 to 30 years with varying adiposity. Regression models were developed for estimating CT-derived fat of 40 men to estimate IAF. Two equations were developed to estimate IAF. The first used only anthropometric measures. Waist circumference and log chest ratio entered the equation and accounted for 67% of the variance. The second model included densitometry-measured percentage fat with the centred product of waist and hip circumferences, accounting for 73% of the variance. Regression equations were also developed to estimate subcutaneous fat area so that the ratio of IAF to subcutaneous fat might be estimated. Although subcutaneous fat could be estimated, the ratio between IAF and subcutaneous fat could not be estimated accurately. A validation of all regression equations developed for male subjects who also completed using a separate validation sample (n = 21). Only the studies with sample characteristics similar to those found in the validation sample validated satisfactorily. Results indicate that anthropometric and densitometry measures cannot be used to estimate CT-derived abdominal fat with precision, however they may be of value in health risk screening of individuals with high levels of IAF. Proper selection procedures with regard to age, adiposity, and morbidity must be used.

Adipose Tissue↗
PubMed1992

Body composition and energy metabolism in resting and exercising muslims during Ramadan fast.

Muslims abstain from food and drink from dawn to sunset during Ramadam, the ninth month of the Islamic calendar. The purpose of this study was to examine the changes that occurred in body composition and both resting and exercise metabolism during a 4 week Ramadan fast. Subjects consumed an average of 1220 kcal each day during Ramadan and lost a significant 1.92 kg body weight. The subjects also lost 2.8% fat. Fat-free mass did not change. Serum sodium, chloride, and protein increased during the first week of Ramadan and returned to the pre-fasting levels during the last week. This indicates a state of dehydratation existed during the first week of Ramadan. Consistent with this is first week 1.13 kg body weight loss with no change in percent fat. First week Ramadan tests showed a significant decrease in VO2max with a return to the pre-test levels in the last week. The lower resting afternoon VO2 suggests that during Ramadan the body's metabolism slows down during the day in order to conserve its energy stores, however, exercise economy as measured by submaximal VO2 in mk/kg/min is not affected.

Adult↗
PubMed1991

Weight training economy as a function of intensity of the squat and overhead press exercise.

The purpose of this investigation was to study the relationship between exercise intensity and weight training economy. Seven subjects performed squat and seated behind the neck press exercises at 60% and 80% of one repetition maximum (1 RM). Addition of net exercise oxygen uptake (VO2) to net recovery VO2 provided an estimate of metabolic cost for the exercise. Estimation of work performed was accomplished by calculation of vertical external work (VEW). Weight training economy was calculated (weight training economy = kcals consumed x VEW-1). The squat was significantly more economical than the overhead press (p = 0.002), and exercise at 60% 1 RM was more economical than exercise at 80% 1 RM (p less than 0.001). Correlations between VEW and kcals consumed at each intensity ranged between 0.85-0.98. It was determined that estimation of metabolic cost of weight training exercise must take into account not only the vertical external work accomplished, but also the intensity of the exercise (% 1 RM). Vertical external work performed on the bar appears to be as accurate as the total vertical external work value in prediction of metabolic cost of the squat and overhead press exercises. Use of the weight training economy values obtained in this study for prediction of metabolic cost will provide values with 4.2%-15.8% prediction error.

Adult↗
PubMed1991

Obesity-related hypertension: evaluation of the separate effects of energy restriction and weight reduction on hemodynamic and neuroendocrine status.

PURPOSE: Although weight reduction generally lowers blood pressure, it is unclear whether the response is due to concurrent dietary changes or to reduced body mass itself. In this study, the independent effects of energy restriction and weight reduction were examined prospectively in 24 obese, hypertensive, normoglycemic women whose dietary intake was tightly controlled. SUBJECTS AND METHODS: Sodium, potassium, and calcium intake, the polyunsaturated/saturated fat ratio, and the proportional composition of carbohydrate, fat, and protein were constant throughout the 5-month protocol. Hemodynamic and neuroendocrine status was evaluated in four 10-day hospital phases: two prior to weight loss (energy balance and then 800-kcal intake), and two after an average loss of 13 kg to normal body weight (800 kcal and then return to energy balance). RESULTS: Fasting serum insulin, triiodothyronine:reverse triiodothyronine ratio, resting metabolic rate, and heart rate declined, and sodium and potassium balances were negative during energy restriction. Catecholamines, renin, aldosterone, plasma volume, cardiac output, and blood pressure showed no consistent response to changes in energy intake. By contrast, weight reduction independently lowered blood pressure, plasma volume, cardiac output, and plasma renin activity. Body fat pattern remained unchanged. CONCLUSION: These results demonstrate that weight loss has a blood pressure-lowering effect that is distinct from energy restriction and that is related to changes in blood volume and cardiac output.

Aged↗
PubMed1990

Perioperative warfarin therapy in combined abdominal lipectomy and intraabdominal gynecological surgical procedures.

The combination of multiple surgical procedures is attractive and convenient to the patient. Increased awareness of wound healing difficulties and pulmonary complications, however, suggest caution with this approach, particularly when combining abdominal lipectomy with intraabdominal procedures. This study confirms the high risk of pulmonary emboli in patients with combined abdominal lipectomy and intraabdominal gynecological procedures. The use of perioperative warfarin may reduce the incidence of pulmonary embolism in patients who have combined abdominal lipectomy and gynecological surgical procedures, and it is not associated with increased bleeding or other postoperative complications.

Adult↗
PubMed1989

The validity of a portable accelerometer for estimating energy expenditure in bicycle riding.

The purpose of the investigation was to determine the validity of a portable vertical accelerometer and a Large-Scale Integrated Motor Activity Monitor (LSI) for estimating energy expenditure in riding a bicycle at various velocities. Instrument placement was either at the knee or ankle. Energy consumption, i.e. oxygen consumption (VO2) was determined during bicycle rides after steady state metabolism was reached. Standard errors of estimate were used to express the accuracy of estimating VO2 from accelerometer or LSI recordings. The reliability of the vertical accelerometer was found to be satisfactory. The vertical accelerometer was also effective for estimating VO2 in bicycling (standard errors of estimate = 3.3 to 4.4 ml.kg-1.min-1). The accuracy of the LSI was not as good; the standard errors of estimate being = 5.9 to 8.5 ml.kg-1.min-1.

Adolescent↗
PubMed1988

Electrical impedance in assessing human body composition: the BIA method.

Fundamental aspects of the body impedance analysis (BIA) method were investigated to determine limitations. This method measures body impedance with a low-level (800 microA) 50-KHz current conducted through the tissues. A linear regression equation was proposed to relate impedance measurements to total body fat. The hydrostatic densitometric method (underwater weighing) was used to validate the proposed mathematical expression. A correlation coefficient of 0.98 between these two methods was obtained. The overall results from this study indicate the usefulness of the BIA method in determining percent body fat in humans provided body fluids are not perturbed several hours before the measurements.

Adipose Tissue↗
PubMed1983

Pulmonary complications following abdominal lipectomy.

Previous reports underestimate the morbidity of a lipectomy, having focused on mortality statistics. Alterations of respiratory kinetics leading to complications do not always correlate with the usual signs and symptoms of respiratory failure. Patients at increased risk, namely, those with obesity, a smoking history, or lung disease, deserve special attention, including appropriate pulmonary function studies in the preoperative and postoperative phase. The following studies are indicated in the preoperative assessment of the high-risk patient: (1) vital capacity, (2) arterial blood gases, and (3) chest radiograph.

Abdomen↗
PubMed1976

Outpatient burns: a prospective study.

1) There is no significant difference in overall wound healing rates between non-antibacterial and antibacterial impregnated dressings used in this study. 2) The burn wound is not sterile. 3) Ease of dressing removal was similar during the first 7 days; thereafter the nitrofurazone dressings were more adherent; however, patient acceptance as subjectively evaluated at the time of dressing change and from the description of intervals between dressing changes did not vary significantly between the two dressings. 4) Pathogenic flora, both gram-positive and gram-negative, were significantly less prevalent in wounds treated with nitrofurazone dressings when the closed technique for burn treatment was utilized.

Adolescent↗