Energy expenditure and physical activity in Prader-Willi syndrome: comparison with obese subjects

Prader-Willi syndrome (PWS) is a complex neurodevelopmental disorder characterized by hypotonia, suck and feeding difficulties, hypogonadism, small hands and feet, developmental delay, hyperphagia and early childhood obesity and a particular facial appearance. The obesity associated with PWS is the result of a chronic imbalance between energy intake and energy expenditure (EE) due to hyperphagia, decreased physical activity, reduced metabolic rate and an inability to vomit. EE is affected by body composition as well as exercise. Individuals with PWS have a lower lean body mass (LBM) compared with controls which may contribute to reduced basal level EE. To determine the relationship among body composition, activity levels and metabolic rates, dual energy X-ray absorptiometry (DEXA) and a whole-room respiration chamber were used to measure body composition, total EE (TEE), resting EE (REE), physical activity, and mechanical work (MW) during an 8 hr monitoring period. The chamber consisted of a live-in whole-room indirect calorimeter equipped with a force platform floor to allow simultaneous measurement of EE, physical activity, and work efficiency during spontaneous activities and standardized exercise. Participants with PWS (27 with 15q11-q13 deletion and 21 with maternal disomy 15 with an average age of 23 years) had significantly decreased TEE by 20% and reduced LBM compared to 24 obese subjects. Similarly, REE was significantly reduced by 16% in the individuals with PWS relative to the comparison subjects. Total MW performed during the 8 hr monitoring period was significantly reduced by 35% in the PWS group. The energy cost of physical activity is related to the duration, intensity and type of activity and the metabolic efficiency of the individual. After adjusting group differences in LBM by analysis of variance, TEE and REE were no longer different between the two groups. Our data indicate that there is a significant reduction of EE in individuals with PWS resulting from reduced activity but also from lower energy utilization due to reduced LBM which consists primarily of muscle.

Comparison of a phone vs clinic approach to achieve 10% weight loss

OBJECTIVE

To compare the efficacy of a phone vs a traditional face-to-face clinic approach to achieve 10% weight loss and weight maintenance.

DESIGN

Twenty-six week, randomized, controlled trial.

SUBJECTS

Twenty-four men and 72 women, ages 25-68 years, with a body mass index (BMI) of 33.2+/-3.8.

MEASUREMENTS

Weight loss at 12 weeks and weight maintenance at 26 weeks were the primary outcomes. Attendance, meal replacements (MRs), fruits/vegetables (F/V), and physical activity (PA) were measured weekly for process evaluation.

RESULTS

Median weight loss (range) from baseline at 12 weeks was significantly different for phone at 10.6 kg (16.6) or 10.4% and clinic at 12.7 kg (19.9) or 13.7%, and both were significantly different when compared with the control group with a weight loss of 0.25 kg (5.6) or 0.24%. Median weight loss at 26 weeks was 12.8 kg (23.4) or 13.0% from baseline for the phone group and 12.5 kg (35.2) or 12.6% from baseline for the clinic group (P>0.05).

CONCLUSION

The median weight loss for both phone and clinic groups at 12 and 26 weeks exceeded the NHLBI guideline of 10% weight loss from baseline. The phone approach may be a viable option to the traditional weight management clinic for both service providers and participants.

SIX MONTHS OF SUPERVISED HIGH-INTENSITY LOW-VOLUME RESISTANCE TRAINING IMPROVES STRENGTH INDEPENDENT OF CHANGES IN MUSCLE MASS IN YOUNG OVERWEIGHT MEN

To determine the effects of a 6-month supervised low-volume resistance training (RT) program (1 set, 85-90%, one repetition maximum, 1RM, 3 d x wk(-1)) on muscular strength (1RM) and skeletal muscle mass (SMM) in previously sedentary, overweight men on an ad libitum diet. Nineteen men were randomly assigned to a control (CON, n = 8) or RT (n = 11) group. The exercise protocol consisted of 5 upper- and 4 lower-body exercises using weight machines. CON maintained their sedentary lifestyle. One RM for upper body (chest press [CP] + lat pull-down [LPD]) and lower body (leg press [LP]) and SMM were assessed at baseline, and at 3 and 6 months. Adherence was 96 +/- 2% with an average time to complete each exercise session of 15 +/- 2 minutes. Volume completed per exercise session significantly increased from baseline (2,812 +/- 670 kg) to 6 months (6,411 +/- 2,128 kg). There was a group by time interaction in 1RM for CP, LPD, and LP. Upper-body strength increased significantly (p < 0.001) (31.3 +/- 9.3%) from baseline to 3 months and from 3 to 6 months (17.9 +/- 8.7%). Lower-body strength also increased significantly from baseline to 3 months (17.8 +/- 16.6%) and from 3 to 6 months (32.0 +/- 33.7%). No changes in upper- or lower-body strength occurred in the CON group. There was no group by time interaction for SMM (CON, 34.5 +/- 2.9 kg vs. RT, 34.2 +/- 2.9 kg; p > 0.05) or for energy intake (p > 0.05). In conclusion, a single set resistance training program at 85% of 1RM, 3 d x wk(-1) resulted in continued increases in muscular strength and a very high adherence rate over a 6-month period in sedentary, overweight men independent of significant changes in SMM. This training protocol may increase adherence and produce long-term increases in muscular fitness as part of an adult fitness program.

Prevalence of the metabolic syndrome in elementary school children

AIM

To determine the prevalence of the metabolic syndrome (MS) and its related components in elementary-aged school children.

METHODS

Three hundred and seventy-five 7-9-y-old boys (n=182) and girls (n=193) in the eastern Kansas area served as participants. Criteria for the MS were the presence of three or more of the following components: 1) central obesity (waist circumference>or=90th percentile in males and females); 2) elevated triglyceride concentrations (>or=1.13 mmol/l); 3) low HDL-C concentrations (<or=1.04 mmol/l in males and females); 4) elevated blood pressure (systolic and/or diastolic>or=90th percentile, age and gender specific); or 5) elevated fasting glucose levels (>or=6.10 mmol/l).

RESULTS

The prevalence of the MS in this sample was 5%, and was similar across gender and race. Fifty percent of the children had no components and 15% had at least two components, with elevated blood pressure the most common component (37%).

CONCLUSION

The MS is prevalent even in young children at rates similarly reported in adolescents.

Author contacts for retrieval of data for a meta-analysis on exercise and diet restriction

OBJECTIVES

The mode of contact and response levels of authors who had been asked to provide missing or incomplete data for a systematic review on diet and exercise interventions for weight loss was examined.

METHODS

We contacted authors by electronic mail, letter, or both. Survival analyses were performed with the Kaplan-Meier method to determine differences in the proportion of responders over time among the different modes of contact and to determine whether response rates differed between authors from the United States and those from other countries. Logistic regression was used to determine whether the number of items requested and publication date influenced the likelihood of response.

RESULTS

Two hundred forty-one (39.9 percent) studies had missing or incomplete data (e.g., sample size, age, caloric restriction, exercise amount, and so on). We were unable to locate ninety-five authors (39.4 percent). Of the remaining authors, forty-six authors (31.5 percent) responded to information requests. Time to respond differed by contact method (p < .05): e-mail (3 +/- 3 days), letter (27 +/- 30 days), and both (13 +/-12 days). Response rates from U.S. authors did not differ from those of other countries.

CONCLUSIONS

Our study suggests poor success in the acquisition of essential information. Given considerable time and resources, weight loss studies require improved reporting standards to minimize the relatively unsuccessful attempt to contact authors for important and necessary information.

Is exercise effective for weight loss with ad libitum diet? Energy balance, compensation, and gender differences

Exercise generally results in less weight loss than expected and it is frequently observed that men and women do not respond equally to exercise for weight loss. This may be caused by differences in compensation by other components of energy balance or to differences in the energy expenditure of exercise observed between genders.

Agreement between skinfold-predicted percent fat and percent fat from whole-body bioelectrical impedance analysis in children and adolescents

PURPOSE

The purpose of the study was to determine the agreement of percent body fat estimates and obesity classification derived via whole-body bioelectrical impedance analysis (% BF-BIA) with percent body fat estimates and obesity classification from skinfolds (% BF-SF) in children and adolescents.

METHODS

BIA and SF data were collected on 609 boys and 645 girls aged 7 to 14 years.

RESULTS

Although moderate correlations were observed between the measures, Bland-Altman analyses revealed fixed and proportional bias, and 95% limits of agreement covered a range of over 20% BF. Agreement of obesity classification was moderately high in boys (Kq = 0.77) and girls (Kq = 0.81), but fewer children were classified as obese via % BF-BIA (14.5%) than via % BF-SF (19.8%).

CONCLUSIONS

The results indicate that whole-body BIA provides % BF estimates that are systematically different from % BF estimates from skinfolds in children and adolescents.

A comparison of meal replacements and medication in weight maintenance after weight loss

OBJECTIVE

To compare the use of meal replacements or medication during weight maintenance subsequent to weight loss using a very low-energy diet (VLED) in overweight or obese adults.

DESIGN

Participants followed a liquid VLED of 2177 kJ for 12 weeks followed by 4 weeks of re-orientation to solid foods. Participants were randomized at week 16 to receive either meal replacements or Orlistat both combined with a structured meal plan containing an energy value calculated to maintain weight loss.

SUBJECTS

Sixty-four women (age = 49.9 +/- 10 y, weight = 101.6 +/- 17.1 kg, height = 164.9 +/- 6.0 cm, BMI = 36.7 +/- 5.4 kg/m(2)) and 28 men (age = 53.7 +/- 9.6 y, weight = 121.8 +/- 16.0 kg, height = 178.7 +/- 5.6 cm, BMI = 37.8 +/- 4.9 kg/m(2)) completed a 1 year weight management program. Behavioral weight management clinics included topics on lifestyle, physical activity (PA), and nutrition. Participants met for 90 min weekly for 26 weeks, and then biweekly for the remaining 26 weeks.

OUTCOMES

Minutes of PA, fruits and vegetables (FV), and pedometer steps were recorded on a daily basis and reported at each group meeting. Body weight was obtained at each group meeting.

RESULTS

During VLED, the MR group decreased body weight by 22.8 +/- 6.1 kg and the Orlistat group decreased body weight by 22.3 +/- 6.1 kg. During weight maintenance, there was no significant group by time interaction for body weight, PA, FV consumption, or pedometer steps. At week 16, the meal replacement group had a body weight of 85.4 +/- 14.3 kg that increased to 88.1 +/- 16.5 kg at 52 weeks (p < 0.05). At week 16, the Orlistat group had a body weight of 85.7 +/- 17.9 kg that increased to 88.5 +/- 20.3 kg at 52 weeks (p < 0.05).

CONCLUSIONS

Subsequent to weight loss from a VLED, meal replacements and Orlistat treatments were both effective in maintaining weight significantly below baseline levels over a 52 week period of time. Meal replacements may be a viable alternative strategy to medications for weight maintenance.

Ingested fat oxidation contributes 8% of 24-h total energy expenditure in moderately obese subjects

The role of ingested fat in the etiology of obesity is controversial. The aims of this study were to determine the contributions of ingested fat oxidation to: 1) 24-h total energy expenditure (TEE), and 2) substrate oxidation during acute stationary cycle exercises in adult humans. Healthy, moderately obese (n = 18; BMI = 31 +/- 1 kg/m2) subjects (8 men; 10 women) were each studied in a whole-room calorimeter for 24 h. They were fed mixed meals (55, 30, and 15% as energy from carbohydrate, fat and protein, respectively) to maintain energy balance. Each subject performed 1255-kJ cycle exercises at 50% VO2max in the calorimeter. Study test meal fat was labeled with carbon-13 (13C). Ingested fat oxidation was estimated from breath 13CO2 excretion and the subject's chamber CO2 production. Total fat and carbohydrate oxidations were estimated from nonprotein respiratory quotient (NP-RQ) values. Endogenous fat oxidation was estimated as the difference between total fat and ingested fat oxidations. TEE was estimated from gas exchanges; 28 +/- 3% of ingested fat was oxidized and it provided 8 +/- 1% of 24-h TEE. During cycle exercises, ingested fat provided 50% of total fat oxidized and 13.0 +/- 2% of energy expended. Endogenous fat oxidation contributed 10.4 +/- 3% of energy expenditure during cycle exercises. This study extended to 24-h observations of previous studies that lasted 6-9 h on ingested fat oxidation in humans. Understanding the factors that promote ingested fat oxidation could lead to more effective obesity intervention programs.

A comparison of three methods of analyzing post-exercise oxygen consumption

Oxygen consumption after exercise is frequently plotted as a function of time and then the area under the curve (AUC) is calculated. Subsequently, this AUC is further manipulated and thus, differences between these manipulations may impact the interpretation of changes in oxygen consumption after exercise. The purpose of this study was to determine if the method of calculating AUC influences the interpretation of changes in post-exercise oxygen consumption in response to long-term aerobic exercise. Forty-three moderately obese, sedentary participants volunteered to participate in this study (26 women and 17 men). All participants performed verified supervised exercise during the study. Supervised treadmill exercise was initially conducted for 3 d/week at 60 % of heart rate reserve (HRR) for 30 min and progressed to 5 d/week at 75 % of HRR for 45 min across the first 4 months. Pre-exercise, exercise, and post-exercise oxygen consumption was measured at baseline and 9 months. AUC was calculated by three methods; total, incremental, and positive incremental. Descriptive statistics and dependent T-tests were calculated for each method of calculating the AUC. In addition, the intra-individual coefficient of variation was determined for each individual for each AUC method. A pearson product moment correlation was calculated for each method to determine the strength of the relationship between pre- and post-training values. The change in post-exercise oxygen AUC after nine months of training was 5.36+/-10.90 L, 2.17+/-7.61 L, and 1.74+/-9.10 L for the total, incremental, and positive incremental methods, respectively. There was significant change in post-exercise total AUC from baseline to 9-months (5.36 +/- 10.90 L), while there was no significant change in incremental or positive incremental AUC. There was a moderately high correlation (r=0.67, p <0.05) between baseline and 9-months for the total AUC method, while there was no significant correlation for incremental and positive incremental AUC methods. These results suggest that the method used to calculate AUC can lead to a different interpretation of the effects of training on post-exercise oxygen consumption. From this data, it appears that analyzing post exercise oxygen consumption with the total area under the curve method has a greater ability to detect a change from aerobic training, than either the positive or incremental area under the curve methods.

Active commuting to and from school and BMI in elementary school children-preliminary data

BACKGROUND

United States National Health Objectives include increasing the proportion of trips made by walking to and from school for children who live within 1.6 km to 50%. The purpose of this objective is to increase the level of physical activity among children. However, the impact of walking, bicycling or skating (active commuting) to and from school on the prevalence of overweight is unknown.

METHODS

Body mass index (BMI) was measured for 320 children (age 10.2+/-0.7 years) in September. Over 5 months, an active commuting index (SI) and daily physical activity were estimated via questionnaire. In April, BMI and body fat were measured.

RESULTS

A significant positive association was found between April BMI and SI adjusting for September BMI (partial r=0.03, P<0.05). Positive associations were found between SI and physical activity before school (r=0.17, P<0.05) and daily moderate intensity physical activity (r=0.13, P<0.05). There were no significant association between SI and BF (P>0.05).

CONCLUSIONS

This preliminary data suggests that active commuting does not appear to provide sufficient amounts of physical activity to attenuate BMI; however, it may contribute to the attainment of physical activity recommendations. Future research is needed to objectively measure the impact of active commuting on the prevalence of overweight.

Beverage Consumption Patterns in Elementary School Aged Children across a Two-Year Period

OBJECTIVE

Existing data was reexamined to determine changes in beverage consumption and associations between beverages consumed and BMI Z-score in children (n = 164) across two years.

METHODS

Beverages (milk, 100% juice, diet soda or sugar sweetened) and total caloric intake were calculated from a 24-hour diet recall. Height and weight were measured to calculate BMI. Subjects were categorized by BMI Z-score as normal weight, overweight, gained weight and lost weight. Data was collected at baseline and year 2.

RESULTS

Significant decreases in milk and increases in diet soda were found over two years in all subjects and normal weight, whereas overweight had a significant increase in diet soda consumption and a decrease in milk consumption that did not reach significance. Change in milk consumption was inversely correlated with sugar-sweetened beverage consumption. Increases in diet soda consumption were significantly greater for overweight and subjects who gained weight as compared to normal weight subjects. Baseline BMI Z-score and year 2 diet soda consumption predicted 83.1% of the variance in year 2 BMI Z-score.

CONCLUSION

Shifts in beverage consumption were found in this convenient sample across two years. Diet soda consumption was the only type of beverage associated with year 2 BMI Z-score, and consumption was greater in overweight subjects and subjects who gained weight as compared to normal weight subjects at two years. Additional longitudinal data examining associations between beverage consumption and BMI is needed in children and adolescents, as consumption of regular and diet soda has become more of a social norm.

Reporting quality of randomized trials in the diet and exercise literature for weight loss

Background

To adequately assess individual studies and synthesize quantitative research on weight loss studies, transparent reporting of data is required. The authors examined the reporting quality of randomized trials in the weight loss literature, focusing exclusively on subject characteristics as they relate to enrollment, allocation, and follow-up.

Methods

An extensive literature review, which included a computerized search of the MEDLINE database, manual searches of bibliographic references, and cross-referencing of 92 review articles was conducted. A checklist, based on CONSORT recommendations, was used to collect information on whether or not authors reported age, gender, co-morbid disease, medication use, race/ethnicity, and postmenopausal status. Also tracked was whether or not initial and final sample size was reported and stratified by gender.

Results

Of 604 possible articles, 231 articles met eligibility criteria. Important subject characteristics were not reported as the following breakdown indicates: age (11%), gender (4%), race/ethnicity (86%), co-morbid disease states (34%), and medication use (92%). Additionally, 21% of articles failed to report initial sample size by gender while 69% neglected to report final sample size by gender.

Conclusion

Inadequate reporting can create difficulties with interpretation and can lead to biased results receiving false credibility. The quality of reporting for weight loss studies needs considerable improvement.

The role of exercise for weight loss and maintenance

Exercise provides a means of increasing energy expenditure and may help adjust energy balance for weight loss and maintenance. At least 30 minutes a day of moderate intensity aerobic exercise per day is recommended for weight loss and maintenance but greater amounts appear to increase the magnitude of weight loss and maintenance. Resistance training has recently been shown to have positive effects on body composition but does not typically show significant decreases in weight. Regardless of weight loss, both aerobic exercise and resistance training have been shown to diminish risk factors for cardiovascular disease and diabetes. Since exercise is only effective if sustained, behavioural strategies such as self-monitoring, goal setting, social support, etc. are used to help individuals start and maintain exercise programs and show improved results compared to exercise programs without behavioural strategies. The available evidence indicates that exercise is an important component of weight loss and perhaps the best predictor of weight maintenance.

Number of days, number of subjects, and sources of variation in longitudinal intervention or crossover feeding trials with multiple days of measurement

Dietary studies are often conducted as longitudinal intervention or crossover trials using multiple days of measurement on each subject during each of several measurement periods, and determining the required numbers of days and subjects is important in designing these studies. Linear mixed statistical models were used to derive equations for precision, statistical power and sample size (number of days and number of subjects) and to obtain estimates of between-subject, period-to-period, and day-to-day variation needed to apply the equations. Two cohorts of an on-going exercise intervention study, and a crossover study of Olestra, each with 14 d of measurement/subject per period, were used to obtain estimates of variability for energy and macronutrient intake. Numerical examples illustrate how the equations for calculating the number of days or number of subjects are applied in typical situations, and sample SAS code is given. It was found that between-subject, period-to-period, and day-to-day variation all contributed significantly to the variation in energy and macronutrient intake. The ratio of period-to-period and day-to-day standard deviations controls the trade-off between the number of days and the number of subjects, and this remained relatively stable across studies and energy and macronutrient intake variables. The greatest gains in precision were seen over the first few measurement days. Greater precision and fewer required days were noted in the study (Olestra) that exerted greater control over the subjects and diets during the feeding protocol.

Multi-point estimation of total energy expenditure: a comparison between zinc-reduction and platinum-equilibration methodologies

Reducing water to hydrogen gas by zinc or uranium metal for determining D/H ratio is both tedious and time consuming. This has forced most energy metabolism investigators to use the "two-point" technique instead of the "Multi-point" technique for estimating total energy expenditure (TEE). Recently, we purchased a new platinum (Pt)-equilibration system that significantly reduces both time and labor required for D/H ratio determination. In this study, we compared TEE obtained from nine overweight but healthy subjects, estimated using the traditional Zn-reduction method to that obtained from the new Pt-equilibration system. Rate constants, pool spaces, and CO2 production rates obtained from use of the two methodologies were not significantly different. Correlation analysis demonstrated that TEEs estimated using the two methods were significantly correlated (r=0.925, p=0.0001). Sample equilibration time was reduced by 66% compared to those of similar methods. The data demonstrated that the Zn-reduction method could be replaced by the Pt-equilibration method when TEE was estimated using the "Multi-Point" technique. Furthermore, D equilibration time was significantly reduced.

Effects of 16 mo of verified, supervised aerobic exercise on macronutrient intake in overweight men and women: the Midwest Exercise Trial

BACKGROUND

It is commonly believed that moderate aerobic exercise leads to changes in diet composition, specifically, an increase in carbohydrate intake at the expense of fat intake.

OBJECTIVE

The goal was to determine the effects of a supervised, long-term program of exercise on the macronutrient intake of previously sedentary, overweight and moderately obese men and women.

DESIGN

Participants (n = 74) were recruited from the university and surrounding communities and were randomly assigned to the exercise or control group. Exercise of moderate intensity was performed for 45 min/d, 5 d/wk, under supervision. Diet intake was ad libitum and was measured for energy and macronutrient composition at baseline and at 5 other occasions across the 16-mo study by use of weighing and measuring techniques. Each measurement consisted of a 2-wk period of direct measurement in the university cafeteria. Food consumption outside the cafeteria during the 2-wk periods (ie, snacks) was measured by multiple-pass 24-h dietary recall procedures.

RESULTS

There were no significant differences for men or women between the exercise and control groups from baseline to 16 mo in fat, carbohydrate, or protein intake expressed as grams or as percentages of total energy intake.

CONCLUSION

Sixteen months of exercise of moderate intensity does not measurably alter the macronutrient intake of young adults.

Glucose and insulin responses following 16 months of exercise training in overweight adults: the Midwest Exercise Trial

The current study examined the insulin and glucose response during an oral glucose tolerance test (OGTT) in overweight young adults prior to and following exercise training in the Midwest Exercise Trial (MET). Subjects (N = 66) were randomly assigned to non-exercise control (CON; 16 females, 13 males) or exercise (EX; 22 females, 15 males) groups. EX performed supervised and verified exercise on 3 to 5 days per week in 20- to 45-minute sessions at 60% to 75% of heart rate reserve. OGTTs and assessments for body mass, body composition, and maximal oxygen consumption (Vo(2) max) were performed at baseline, and after 9 and 16 months of training. Blood was collected during a 75-g OGTT and analyzed for glucose and insulin concentrations with the total area under the glucose and insulin curves used in the analysis. The EX males had significant decreases from baseline to 9 months in body mass (94.8 +/- 12.5 to 89.2 +/- 9.8 kg) and percent fat (28.3 +/- 4.8 to 24.2 +/- 3.9) with no further changes at 16 months. CON females had significant increases in body mass (78.2 +/- 6.4 to 81.1 +/- 8.1 kg) and percent fat (36.6 +/- 4.2 to 37.8 +/- 4.7) from baseline to 16 months. Vo(2) max increased significantly from baseline to 9 months in the EX males (3.67 +/- 0.62 to 4.36 +/- 0.55 L/min) and EX females (2.53 +/- 0.32 to 2.99 +/- 0.42 L/min). For glucose area under the curve, there were no significant differences between EX or CON across the 16 months of the study. For insulin area under the curve, there was a significant decrease for male EX from baseline to 9 months (12,535 +/- 6,114 to 8,390 +/- 4,231 microU/L/180 min). We conclude that regular exercise in healthy, previously sedentary overweight adult males leads to improvements in Vo(2) max and weight loss and a reduction in the insulin concentration required to dispose of a set glucose load. In females, improvement in Vo(2) max without weight loss does not lead to improvement in insulin sensitivity.

Adherence and attrition with intermittent and continuous exercise in overweight women

Few people are active to the levels recommended by Healthy People 2010. Intermittent exercise has been promoted as an exercise prescription which may enable more people to meet recommended guidelines. However, few data are available on intermittent exercise over the long-term. The purpose of the current study was to compare the effects of long-term (72 weeks) continuous (CON) and intermittent (INT) exercise on attrition and adherence in previously sedentary, moderately obese females. Participants were randomized to continuous walking at 60 to 75% of maximum aerobic capacity, 3 days per week, 30 minutes per session, or intermittent exercise for two 15-minute sessions, 5 days per week. Adherence was calculated as the number of sessions completed compared to the number of sessions prescribed. At 12-week intervals, attrition was calculated as the number of participants in the study compared to the total number of participants originally enrolled. For the participants who completed the study, body weight decreased for CON from 80.17 +/- 5.75 kg at baseline to 79.70 +/- 5.40 at 16 months (p < 0.05). For INT, body weight did not change from baseline (85.85 +/- 13.13 kg) to 16 months (85.05 +/- 12.90 kg). By design, INT walked significantly (p < 0.05) further (819 +/- 128 km) compared to CON (527 +/- 46 km). Attrition was 58% for both groups baseline to 72 weeks. However, attrition was greater for CON (38 %) compared to INT (16%) in the first 24 weeks. Adherence was excellent for both groups (> 83%) throughout the study. These results suggest that intermittent and continuous exercise both have considerable attrition rates within 72 weeks of exercise initiation; however, the pattern of attrition differs considerably. That is, it appears that intermittent exercise may reduce attrition in the first 24 weeks of an exercise program; however, attrition does not appear to be different than continuous exercise at 72 weeks.

Time course for changes in aerobic capacity and body composition in overweight men and women in response to long-term exercise: the Midwest Exercise Trial (MET)

OBJECTIVE

To determine the time course for changes in aerobic capacity, body weight (BW), and composition in overweight adults in response to a supervised exercise trial with a targeted energy expenditure of 2000 kcal week(-1).

DESIGN

The Midwest Exercise Trial (MET) was a randomized, controlled, 16-month verified, supervised exercise trial. Aerobic exercise progressed to 45 min day(-1), 5 days week(-1) over 6-months and was then maintained for 10 months. Controls maintained their normal physical activity and all participants maintained ad libitum diets.

SUBJECTS

A total of 131 participants were randomized to exercise or control groups and 74 completed the intervention and all laboratory testing.

MEASUREMENTS

At baseline and months 4, 9, 12, and 16, aerobic capacity (VO(2max) ) was measured by indirect calorimetry, BW by digital scale, and fat weight and fat-free weight by hydrostatic weighing.

RESULTS

Aerobic capacity (ml kg(-1) min(-1)) increased (P<0.05) from baseline (39.2+/-5.2, mean+/-s.d.) to 9 months (48.8+/-4.3) in exercising men as well as women (32.8+/-4.2-39.6+/-5.5) with no significant changes occurring at 12 or 16 months. From baseline to 9 months BW (94.0+/-12.6-88.7+/-9.7 kg) and fat weight (26.8+/-6.8-21.8+/-4.5 kg) significantly decreased in exercising men with no changes occurring at 12 or 16 months. There were no changes in fat-free weight across the 16 months for exercising men or for BW or composition in exercising women. Further, there were no significant changes for the control men for aerobic capacity, BW, or body composition across 16 months. Women in the control group showed significant increases in weight of 2.9+/-5.5 kg and fat weight of 2.1+/-4.8 kg at 16 months only.

CONCLUSIONS

We recommend that investigations that use exercise without diet as the stimulus for weight loss have at least a 9-month duration to provide sufficient time for the full effects to be realized, should such effects be present.

The validity of the Stanford Seven-Day Physical Activity Recall in young adults

PURPOSE

To evaluate the criterion validity of the 7-Day Physical Activity Recall (7D-PAR) and factors associated with reporting error, in a sample of moderately overweight, young adult men and women.

METHODS

Average total daily energy expenditure (TDEE) and physical activity energy expenditure (PAEE) from the 7D-PAR were compared with the same parameters assessed by doubly labeled water in 17 men, age = 23.9 +/- 3.8 yr, and 29 women, age = 23.3 +/- 4.6 yr, who volunteered to participate in a 16-month supervised aerobic exercise trial. PAEE was estimated from the 7D-PAR and from DLW [0.9 * TDEE -resting metabolic rate (RMR) (indirect calorimetry)]. In addition, peak oxygen uptake and percent body fat were obtained.

RESULTS

No significant differences in TDEE (kJ.d-1) were noted between the 7D-PAR (11825 +/- 1779) and DLW (11922 +/- 2516) for the complete sample (N = 46) or for men (7D-PAR = 13198 +/- 1638, DLW = 13885 +/- 2754) or women (7D-PAR = 11018 +/- 1323, DLW = 10771 +/- 1457. The mean PAEE from the 7D-PAR was not different from DLW in the total sample (7D-PAR = 3286 +/- 502, DLW = 3508 +/- 1863) as well as in men (7D-PAR = 3650 +/- 490, DLW = 3989 +/- 2461) and women (3073 +/- 377, DLW = 3223 +/- 1360). In a regression model, PAEE, peak oxygen uptake, gender and percent fat accounted for 86% of the reporting error in total daily energy expenditure when using the 7D-PAR.

CONCLUSION

The 7D-PAR provided a reasonable estimate of both the mean TDEE and PAEE in this sample; however, estimates of energy expenditure on an individual basis using the PAR were subject to considerable error.

Effects of a 16-month randomized controlled exercise trial on body weight and composition in young, overweight men and women: the Midwest Exercise Trial

BACKGROUND

In light of the current obesity epidemic, treatment models are needed that can prevent weight gain or provide weight loss. We examined the long-term effects of a supervised program of moderate-intensity exercise on body weight and composition in previously sedentary, overweight and moderately obese men and women. We hypothesized that a 16-month program of verified exercise would prevent weight gain or provide weight loss in the exercise group compared with controls.

METHODS

This was a randomized controlled efficacy trial. Participants were recruited from 2 midwestern universities and their surrounding communities. One hundred thirty-one participants were randomized to exercise or control groups, and 74 completed the intervention and all laboratory testing. Exercise was supervised, and the level of energy expenditure of exercise was measured. Controls remained sedentary. All participants maintained ad libitum diets.

RESULTS

Exercise prevented weight gain in women and produced weight loss in men. Men in the exercise group had significant mean +/- SD decreases in weight (5.2 +/- 4.7 kg), body mass index (calculated as weight in kilograms divided by the square of height in meters) (1.6 +/- 1.4), and fat mass (4.9 +/- 4.4 kg) compared with controls. Women in the exercise group maintained baseline weight, body mass index, and fat mass, and controls showed significant mean +/- SD increases in body mass index (1.1 +/- 2.0), weight (2.9 +/- 5.5 kg), and fat mass (2.1 +/- 4.8 kg) at 16 months. No significant changes occurred in fat-free mass in either men or women; however, both had significantly reduced visceral fat.

CONCLUSIONS

Moderate-intensity exercise sustained for 16 months is effective for weight management in young adults.

Validation of energy intake measurements determined from observer-recorded food records and recall methods compared with the doubly labeled water method in overweight and obese individuals

BACKGROUND

Measurements of dietary intake in obese and overweight populations are often inaccurate because food intakes are underestimated.

OBJECTIVE

The purpose of this study was to evaluate the validity of the combined use of observer-recorded weighed-food records and 24-h snack recalls in estimating energy intakes in overweight and obese individuals.

DESIGN

Subjects were 32 healthy women and 22 healthy men with mean body mass indexes (in kg/m(2)) of 29.5 and 30.3, respectively. Energy intake (EI) was measured over 2 wk in a university cafeteria. No restrictions were made on meal frequency or EI. To document food consumed outside the cafeteria, 24-h snack recalls were conducted before meals. Energy expenditure (EE) was measured with the doubly labeled water (DLW) method (EE(DLW)). Energy balance was determined by measuring body weight at the beginning and end of the 2-wk period.

RESULTS

The mean EI in the women (10.40 +/- 1.94 MJ/d) and men (14.37 +/- 3.21 MJ/d) was not significantly lower than the EE(DLW) in the women (10.86 +/- 1.76 MJ/d) and men (14.14 +/- 2.83 MJ/d). The mean EI represented 96.9 +/- 17.0% and 103 +/- 18.9% of the measured EE for women and men, respectively. There were no significant changes in weight in the group as a whole or by sex at the end of the testing period; the men lost 0.23 +/- 1.58 kg and the women lost 0.25 +/- 1.09 kg.

CONCLUSION

The combination of observer-recorded food records and 24-h snack recalls is a valid method for measuring EI in overweight and obese individuals.

A comparison of methods for analyzing glucose and insulin areas under the curve following nine months of exercise in overweight adults

OBJECTIVE

We examined three methods for calculating the area under the curve (AUC) following an oral glucose tolerance test (OGTT) in overweight adults prior to and after 9 months of exercise.

METHOD

Subjects (n=27) were randomly assigned to a control (CON, n=9) or intervention (INT, n=18) group. INT performed supervised exercise 5 days per week, 45 min per session, at 65% of heart rate reserve. OGTTs were administered pre- and post-training. Blood was collected during a 75 g OGTT and analyzed for glucose (GLU) and insulin (INS) concentrations. AUCs were calculated using the incremental, positive incremental, and total AUC methods and the difference scores for pre- and post-training were determined.

RESULTS

No differences were observed among the methods for glucose AUC for either group. Significant differences were observed for INT insulin AUC with total AUC (1525+/-3291 microU/1/180 min) significantly greater than incremental AUC (1112+/-3229 microU/1/180 min) or positive incremental AUC (1085+/-3195 microU/I/180 min). Total insulin AUC was significantly reduced following training for INT, while incremental and positive incremental insulin AUCs showed no change.

CONCLUSION

These data suggest that the method of used to calculate AUC may affect the interpretation of whether or not an intervention was effective.

American College of Sports Medicine position stand. Appropriate intervention strategies for weight loss and prevention of weight regain for adults

In excess of 55% of adults in the United States are classified as either overweight (body mass index = 25-29.9 kg.m(-2)) or obese (body mass index > or = 30 kg.m(-2)). To address this significant public health problem, the American College of Sports Medicine recommends that the combination of reductions in energy intake and increases in energy expenditure, through structured exercise and other forms of physical activity, be a component of weight loss intervention programs. An energy deficit of 500-1000 kcal.d-1 achieved through reductions in total energy intake is recommended. Moreover, it appears that reducing dietary fat intake to <30% of total energy intake may facilitate weight loss by reducing total energy intake. Although there may be advantages to modifying protein and carbohydrate intake, the optimal doses of these macronutritents for weight loss have not been determined. Significant health benefits can be recognized with participation in a minimum of 150 min (2.5 h) of moderate intensity exercise per week, and overweight and obese adults should progressively increase to this initial exercise goal. However, there may be advantages to progressively increasing exercise to 200-300 min (3.3-5 h) of exercise per week, as recent scientific evidence indicates that this level of exercise facilitates the long-term maintenance of weight loss. The addition of resistance exercise to a weight loss intervention will increase strength and function but may not attenuate the loss of fat-free mass typically observed with reductions in total energy intake and loss of body weight. When medically indicated, pharmacotherapy may be used for weight loss, but pharmacotherapy appears to be most effective when used in combination with modifications of both eating and exercise behaviors. The American College of Sports Medicine recommends that the strategies outlined in this position paper be incorporated into interventions targeting weight loss and the prevention of weight regain for adults.

Transesophageal echocardiographic abnormalities in a case of cardiac sarcoidosis

Sarcoidosis is a granulomatous disease that may involve multiple organ systems, including the heart. Manifestations include atrial and ventricular arrhythmias, conduction abnormalities, congestive cardiac failure, pericarditis, and sudden death. Whereas cardiac involvement is a relatively common finding at autopsy, antemortem diagnosis is often missed because the clinical manifestations are nonspecific, and the sensitivity and specificity of investigations are low. We report a case of a 62-year-old woman who had clinically significant cardiac sarcoidosis associated with echocardiographic abnormalities that had not been reported previously in association with this condition.

Echocardiographic characterization of cardiomyopathy in Friedreich's ataxia with tissue Doppler echocardiographically derived myocardial velocity gradients

BACKGROUND

Conventional and tissue Doppler echocardiographically derived myocardial velocity gradients (MVGs) were used to characterize the myocardium in patients with Friedreich's ataxia (FRDA), and the relationship between MVGs and the mutation in the FRDA gene, a GAA triplet repeat expansion, was investigated.

METHODS AND RESULTS

We studied 29 patients with FRDA (10 men, mean age 31+/-9 years) who were homozygous for the GAA expansion in the FRDA gene and were without cardiac symptoms. A comparison was made with a group of 30 age-matched control subjects. In patients with FRDA, interventricular septal thickness (1.17+/-0.26 versus 0.85+/-0.13 cm, P:<0.005), posterior left ventricular wall thickness (1.00+/-0.24 versus 0.88+/-0.15 cm, P:<0.01), and left atrial diameter (3.3+/-0.5 versus 2.9+/-0.3 cm, P:=0.01) were increased compared with control subjects. MVGs were reduced in FRDA during systole (3.1+/-1.2 versus 4.5+/-0.5 s(-1), P:<0.0001) and in early diastole (4.9+/-2.7 versus 8.8+/-1.8 s(-1), P:<0.0001) but increased in late diastole (2.0+/-1. 3 versus 1.1+/-0.9 s(-1), P:<0.01). The strongest relationship was seen between age-corrected early diastolic MVGs and the GAA expansion in the smaller allele of the FRDA gene (r=-0.68, P:<0. 0001).

CONCLUSIONS

MVGs offer a means of further characterizing the myocardial abnormalities in patients with FRDA. Early diastolic MVGs appear to relate most closely to the genetic abnormality and the consequential reduction in frataxin protein.

Impact of closed versus open venous reservoirs on patient outcomes in isolated coronary artery bypass graft surgery

Data were collected retrospectively on 1,681 consecutive isolated coronary artery bypass graft patients at Millard Fillmore Hospital (Buffalo, New York, USA) undergoing coronary artery bypass. No patients were excluded. There were 616 patients in the open circuit group and 1,065 in the closed circuit group. Patients in the closed circuit group exhibited a trend towards a higher incidence of most pre-existing comorbidities, with acute myocardial infarction, pre-existing cerebrovascular disease and the incidence of extensively calcified aortas all being significantly higher. Significantly different postbypass outcomes favored the closed circuit group, with levels of sepsis of 1% for open and 0% for closed and respiratory failure of 4% for open and 1% for closed. The length of stay approached significance with a p-value of 0.057 (open 9.85 days and closed 7.53). Use of an open circuit was a significant, independent predictor for increased use of units of packed red blood cells and total units of blood products. This study provides evidence that closed venous reservoirs can favorably impact surgical outcomes and reduce resulting healthcare costs.

Differentiation between restrictive cardiomyopathy and constrictive pericarditis by early diastolic doppler myocardial velocity gradient at the posterior wall

BACKGROUND

The differential diagnosis between restrictive cardiomyopathy (RCM) and constrictive pericarditis (CP) is challenging and, despite combined information from different diagnostic tests, surgical exploration is often necessary.

METHODS AND RESULTS

A group of 55 subjects (mean age, 63+/-11 years; 36 men and 19 women) were enrolled in the study; 15 had RCM, 10 had CP, and 30 were age-matched, normal controls. The diagnosis of RCM was supported by a biopsy; in the CP group, the diagnosis was confirmed either surgically or at autopsy. All patients underwent a transthoracic echocardiogram that included the assessment of Doppler myocardial velocity gradient (MVG), as measured from the left ventricular posterior wall during the predetermined phases of the cardiac cycle. MVG was lower (P<0.01) in RCM patients compared with both CP patients and normal controls during ventricular ejection (2. 8+/-1.2 versus 4.4+/-1.0 and 4.7+/-0.8 s(-1), respectively) and rapid ventricular filling (1.9+/-0.8 versus 8.7+/-1.7 and 3.7+/-1.4 s(-1), respectively). Additionally, during isovolumic relaxation, MVG was positive in RCM patients and negative in both CP patients and normal controls (0.7+/-0.4 versus -1.0+/-0.6 and -0.4+/-0.3 s(-1), respectively; P<0.01). During atrial contraction, MVG was similarly low (P<0.01) in both RCM and CP patients compared with normal controls (1.6+/-1.7 and 1.7+/-1.8 versus 3.8+/-0.9 s(-1), respectively).

CONCLUSIONS

Doppler myocardial imaging-derived MVG, as measured from the left ventricular posterior wall in early diastole during both isovolumic relaxation and rapid ventricular filling, allows for the discrimination of RCM from CP.

The effects of 18 months of intermittent vs. continuous exercise on aerobic capacity, body weight and composition, and metabolic fitness in previously sedentary, moderately obese females

OBJECTIVES

To compare the effects of 18 months of continuous vs intermittent exercise on aerobic capacity, body weight and composition, and metabolic fitness in previously sedentary, moderately obese females.

DESIGN

Randomized, prospective, long-term cohort study. Subjects performed continuous exercise at 60-75% of maximum aerobic capacity, 3 days per week, 30 min per session, or exercised intermittently using brisk walking for two, 15 min sessions, 5 days per week.

MEASURES

Aerobic capacity, body weight, body composition, and metabolic fitness (blood pressure, lipids, glucose and insulin).

RESULTS

Significant improvements for aerobic capacity of 8% and 6% were shown for the continuous and intermittent exercise groups, respectively. Weight loss for the continuous exercise group was significant at 2.1% from baseline weight and the intermittent group was essentially unchanged. The continuous group showed a significant decrease in percentage of body fat and fat weight while the intermittent group did not. HDL cholesterol and insulin were significantly improved for both groups.

CONCLUSIONS

In previously sedentary, moderately obese females, continuous or intermittent exercise performed long-term may be effective for preventing weight gain and for improving some measures of metabolic fitness.