Effects of exercise and lifestyle modification on fitness, insulin resistance, skeletal muscle oxidative phosphorylation and intramyocellular lipid content in obese children and adolescents.

BACKGROUND: Obesity is associated with poor fitness and adverse metabolic consequences in children. OBJECTIVE: To investigate how exercise and lifestyle modification may improve fitness and insulin sensitivity in this population. DESIGN AND SUBJECTS: Randomized controlled trial, 21 obese (body mass index ≥ 95% percentile) subjects, ages 10 to 17 years. METHODS: Subjects were given standardized healthful lifestyle advice for 8 weeks. In addition, they were randomized to an in-home supervised exercise intervention (n = 10) or control group (n = 11). MEASUREMENTS: Fasting laboratory studies (insulin, glucose, lipid profile) and assessments of fitness, body composition, skeletal muscle oxidative phosphorylation and intramyocellular lipid content (IMCL), were performed at baseline and study completion. RESULTS: Subjects were 13.0 ± 1.9 (standard deviation) years old, 72% female and 44% non-white. Exercise improved fitness (P = 0.03) and power (P = 0.01), and increased IMCL (P = 0.02). HOMA-IR decreased among all subjects in response to lifestyle modification advice (P = 0.01), regardless of exercise training assignment. In univariate analysis in all subjects, change in cardiovascular fitness was associated with change in HOMA-IR. In exploratory analyses, increased IMCL was associated with greater resting energy expenditure (r = 0.78, P = 0.005) and a decrease in fasting respiratory quotient (r = -0.70, P = 0.02) (n = 11). CONCLUSIONS: Change in fitness was found to be related to change in insulin resistance in response to lifestyle modification and exercise in obese children. IMCL increased with exercise in these obese children, which may reflect greater muscle lipid oxidative capacity.

Physician involvement in the management of obesity as a primary medical condition.

As the obesity epidemic escalates, increasing numbers of patients present with serious comorbidities related to excess body weight. Obesity should be recognized and treated as a primary medical condition that is progressive, chronic, and relapsing. Effective treatment of obesity has been shown to reduce cardiovascular risk factors and comorbid conditions. Physician involvement is necessary for medical assessment, management, counseling, and coordination of multidisciplinary obesity treatment. Obese patients who receive counseling and weight management from physicians are significantly more likely to undertake weight management programs than those who do not. Obesity treatment guidelines and materials are available from various health organizations. A comprehensive weight management program must include dietary adjustments, increased physical activity, and behavioral modification. Nutritional modifications should take into account the diet's energy content, composition, and suitability for the individual patient. The physical activity component should be safe and practical, including aerobic activity, strength training, and increased daily lifestyle activities. Various behavioral strategies enable the patient to make lifestyle changes that will promote weight loss and management. Adjunct therapies may serve to support lifestyle modifications in severe or resistant cases of obesity. Models for multidisciplinary care vary depending on whether they are designed for an individual medical practice or as part of the health care services of a larger facility. Lifestyle changes for healthy weight management must be permanently incorporated into a patient's daily lifestyle to reduce obesity and its associated health risks. Such intervention is necessary if the growing epidemic of obesity is to be slowed and reversed.

Low compliance with national standards for cardiovascular emergency preparedness at health clubs.

There is heightened concern that older adults and individuals with occult or known heart disease are exercising at fitness facilities that do not provide adequate cardiovascular screening and emergency procedures, as outlined in contemporary recommendations. To evaluate adherence to these standards, we surveyed 122 randomly chosen fitness clubs in Ohio (53% response rate; n = 65) that included > 110,000 total members. Special programs for older adults, cardiac patients, or both, were offered at 52% of these clubs. More than one fourth of the clubs (28%) failed to employ pre-entry screening to identify members with signs, symptoms, or history of cardiovascular disease, even though 17% reported one or more cardiovascular emergencies (ie, acute myocardial infarction, sudden cardiac death, or both) in their facility during the past 5 years. Moreover, a majority of the clubs (53%) had no written emergency response plan and 92% failed to conduct emergency response drills as described in published national standards. Only 3% of the centers reported having automated external defibrillators. These findings indicate that staff at public fitness facilities must work to identify members with signs, symptoms, or history of cardiovascular disease and prepare for prompt and appropriate responses to cardiovascular emergencies as described in contemporary national recommendations. Such risk management procedures may reduce exercise-related cardiovascular events among the escalating number of moderate-to-high-risk adults who are being mainstreamed into health and fitness facilities.

Obesity and cardiovascular disease risk: research update.

The obesity epidemic has reached unprecedented proportions in Western society. Evidence continues to accumulate that obesity is associated with significant morbidity and mortality and in particular that it is an independent risk factor for cardiovascular disease (CVD). The association of obesity with CVD and its risk factors, including hypertension, dyslipidemia, glucose intolerance, and impaired hemostasis is becoming more clearly understood. An increasing body of data indicates that risk factors tend to cluster in obese individuals and may act synergistically to increase these people's risk for CVD. Individuals with disproportionate visceral adiposity are at significantly greater risk for CVD. Adult weight gain also underlies the development of many risk factors and augments the risk of CVD. Physicians can play a vital and active role in the prevention and treatment of obesity and overweight and thereby reduce patients' CVD risk.

Exercise and obesity.

The prevalence of obesity has increased dramatically during the past decade in the USA. This is despite an estimated 50 million Americans who try to lose weight each year. The increasing prevalence of obesity is particularly alarming due to the numerous health implications associated with this condition, including coronary artery disease, hypertension, diabetes, hyperlipidemia, cancer, and various musculoskeletal conditions. The economic impact of treating illnesses associated with obesity has been estimated to be US$40 billion in the USA. Dieting is largely ineffective in maintaining initial weight loss as numerous studies suggest the majority of dieters regain all lost weight with 3-5 years. On, the other hand, regular exercise has been shown to be one of the best predictors of successful weight maintenance. Moreover, studies indicate that improved fitness through regular physical activity reduces cardiovascular morbidity and mortality for overweight individuals even if they remain overweight. Providing advice about exercise to overweight or obese individuals requires explicit information about the frequency, intensity, duration, and type of physical activity that should be performed. The ultimate goal for the exercising obese patient is to make a life-long commitment to achieving reasonable energy expenditure through routine physical activity.

Accuracy of a pretest questionnaire in exercise test protocol selection.

Proper exercise test protocol selection is essential to allow adequate time for observation of subjective and physiologic responses to exercise, as well as provider-patient interaction and patient comfort. This study evaluates the accuracy of a pretest questionnaire in predicting exercise capacity for exercise test protocol selection and compares the accuracy of this questionnaire when ramp versus step protocols are used.

Effect of body composition on oxygen uptake during treadmill exercise: body builders versus weight-matched men.

Oxygen uptake (VO2) during treadmill exercise is directly related to the speed and grade, as well as the participant's body weight. To determine whether body composition also affects VO2 (ml.kg-1.min-1) during exercise, we studied 14 male body builders (M weight = 99 kg, SD = 7; M height = 180 cm, SD = 8; M body fat = 8%, SD = 3; M fat free mass = 91 kg, SD = 7) and 14 weight-matched men (M weight = 99 kg, SD = 9; M height = 179 cm, SD = 5; M body fat = 24%, SD = 5; M fat free mass = 73 kg, SD = 9). Percentage of body fat, t(13) = 8.185, p < .0001, and fat free mass, t(13) = 5.723, p < .0001, were significantly different between groups. VO2 was measured by respiratory gas analysis at rest and during three different submaximal workrates while walking on the treadmill without using the handrails for support. VO2 was significantly greater for the lean, highly muscular men at rest: 5.6 +/- 1 vs. 4.0 +/- 1 ml.kg-1.min-1, F(1, 26) = 21.185, p < .001; Stage 1: 1.7 mph/10%, 18.5 +/- 2 vs. 16.1 +/- 2 ml.kg-1.min-1, F(1, 26) = 6.002, p < .05; Stage 2: 2.5 mph/12%, 26.6 +/- 3 vs. 23.1 +/- 2 ml.kg-1.min-1, F(1, 26) = 7.991, p < .01; and Stage 3:3.4 mph/14%, 39.3 +/- 5 vs. 33.5 +/- 5 ml.kg-1.min-1, F(1, 26) = 7.682, p < .01, body builders versus weight-matched men, respectively. However, net VO2 (i.e., exercise VO2 - rest VO2) was not significantly different between the two groups at any of the matched exercise stages. The findings from this study indicate that VO2 during weight-bearing exercise performed at the same submaximal workrate is higher for male body builders compared to that measured in weight-matched men and that which is predicted by standard equations. These observed differences in exercise VO2 appear to be due to the higher resting VO2 in highly muscular participants.

Comparison of cardiopulmonary responses in obese women using ramp versus step treadmill protocols.

The purpose of this study was to evaluate whether individual ramp protocol treadmill testing is superior to frequently used step protocols in eliciting peak cardiopulmonary responses in obese women. The main findings indicate that protocol selection based on predicted pretest individual exercise capacity is more important than whether a ramp or step protocol is used.

Cardiovascular screening and emergency procedures at health clubs and fitness centers.

A survey of 110 fitness centers in Massachusetts reveals that many do not follow generally accepted guidelines for administering preparticipation cardiovascular screening, obtain physician consent for individuals with known cardiovascular disease, and prepare for emergency situations should they occur. Thus, the promotion of physical activity to the general public now underway in the United States must also coincide with better screening at all fitness centers to maximize the potential for safe exercise participation at fitness centers.

Prediction of oxygen uptake and energy expenditure during exercise in obese women.

PURPOSE: For patients concerned with weight loss, monitoring the energy balance between daily dietary intake and exercise expenditure can be useful. Formulas commonly used to estimate the energy costs of exercise were previously derived from healthy men of normal body weight. The purpose of this study was to determine the relationship between measured and predicted exercise energy expenditure for obese women. METHODS: Oxygen uptake (VO2) was measured using respiratory gas analysis in 45 obese (92 +/- 16 kg; 40 +/- 7% fat) and 10 normal weight (control) (58 +/- 5 kg; 21 +/- 6% fat) women during progressive exercise on a motorized treadmill. VO2 was also calculated at matched workrates using a regression equation published by the American College of Sports Medicine. The relationship between predicted versus measured VO2 was determined using least squares regression analysis. RESULTS: The slope of the regression line for measured versus predicted VO2 for controls (y = 0.98x +/- 0.56; P < .001) was different than that of obese women (y = 0.75x +/- 3.06; P < .001). The slope of the regression line for controls was in close approximation to the line of identity, whereas the slope for obese was below it. Using VO2 to calculate kcal, measured energy expenditure, was significantly lower than predicted energy expenditure for obese subjects, but not for controls at several matched workrates: Stage III (213 +/- 40 versus 225 +/- 38 kcal per 30 minutes, P < .001); stage 4 (292 +/- 55 versus 340 +/- 58 kcal per 30 minutes, P < .001); and stage 5 (330 +/- 55 versus 412 +/- 70 kcal per 30 minutes, P < .001) obese measured versus obese predicted, respectively. CONCLUSIONS: The authors conclude that the standard prediction equation gives a better estimation of VO2 for women who have average body weight and body fat than for obese women. This may, in part, be due to the differences in weight and/or fat mass between these subjects and those used to derive this equation. These findings should be considered when estimates of VO2 and energy expenditure are used rather than direct measures for obese women.

Implementing hospital library automation: the GaIN project. Georgia Interactive Network for Medical Information.

The GaIN (Georgia Interactive Network for Medical Information) Hospital Libraries' Local Automation Project was a one-year, grant-funded initiative to implement an integrated library system in three Georgia hospitals. The purpose of the project was to install the library systems, describe the steps in hospital library automation, and identify issues and barriers related to automation in small libraries. The participating hospitals included a small, a medium, and a large institution. The steps and time required for project implementation were documented in order to develop a decision checklist. Although library automation proved a desirable approach for improving collection accessibility, simplifying daily routines, and improving the library's image in the hospital, planners must be sure to consider equipment as well as software support, staffing for the conversion, and training of the library staff and end users.

Hypnotic underestimation of time: the busy beaver hypothesis.

Two experiments tested the hypothesis that the hypnotic underestimation of time is mediated by attentional processing. In Experiment 1, variations in the demands placed on attentional resources produced substantial differences in the subjective estimates of identical length intervals occurring within a hypnotic context. In Experiment 2, attentional manipulation was assessed in both hypnotic and waking contexts. Time judgments were again found to vary with attentional demands but not with hypnotic context. The results are consistent with a busy beaver hypothesis, which holds that hypnotic, as well as nonhypnotic, time estimates are a by-product of the attentional processing demands of the task.

Comparison of submaximal exercise responses using the Bruce vs modified Bruce protocols.

The purpose of this study was to determine whether the parameters commonly used to evaluate a training effect can be compared when serial tests are performed using different protocols. Thirty-two patients with stable coronary artery disease performed both the standard and modified Bruce protocols in a random order, 1 h apart. Physiologic variables at matched exercise stage I including heart rate (99 +/- 12 vs 101 +/- 14 bpm), rate-pressure product (15 +/- 3 vs 15 +/- 3 bpm x mmHg x 10(3)), and VO2 (13.5 +/- 2.1 vs 13.0 +/- 3.0 ml.kg-1 x min-1) were not significantly different for exercise tests performed using the standard vs modified Bruce protocols respectively. Similarly, these parameters were also nearly identical at matched exercise stage II. However, peak VO2 was significantly higher using the standard vs modified Bruce protocol, although the difference was small. Therefore, these data indicate that a difference in the heart rate response at matched submaximal workrates on tests using these two protocols before and after a training program is most likely due to a training effect. Conversely, improvements in peak VO2 using the standard vs modified Bruce are at least in part due to inherent differences in responses between these two protocols.

Comparison of ischemic and physiologic responses during exercise tests in men using the standard and modified Bruce protocols.

The importance of low-level (warm-up) exercise for reducing exercise-induced myocardial ischemic symptoms in patients with coronary artery disease is well-recognized by clinicians. Whether altering the abruptness of exercise, such as that which occurs during different frequently used testing protocols, affects myocardial ischemic variables and maximal exercise capacity has not been resolved. This study seeks to determine the effects of altering the increment of work-rate change per exercise stage on both the ischemic threshold and maximal exercise capacity using 2 frequently used exercise testing protocols. Thirty-two patients with documented coronary artery disease and previously positive exercise tests (ischemic ST depression greater than or equal to 1.0 mm) performed symptom-limited exercise tests using both the standard and modified Bruce protocols in random order, 1 hour apart. Exercise electrocardiograms were analyzed to determine the ischemic threshold, defined as heart rate at onset of greater than or equal to 1.0 mm ischemic ST depression. Patients achieved a higher peak heart rate (124 +/- 19 vs 117 +/- 21 beats/min; p less than 0.0001), rate-pressure product (21.4 +/- 3.9 vs 19.8 +/- 4.1 beats/min x mm Hg x 10(3); p less than or equal to 0.0001) and oxygen consumption (VO2) (18.5 +/- 3.7 vs 16.5 +/- 4.4 ml/kg/min; p less than or equal to 0.001) with the standard than with the modified Bruce protocol. At matched submaximal exercise stages there were no differences in VO2, heart rate or oxygen pulse between protocols. Time to ischemic threshold was significantly reduced with the standard compared with the modified Bruce protocol (312 +/- 107 vs 607 +/- 221 seconds; p less than 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Ethnic-sensitive work with Hmong refugee children.

This article examines three distinguishing characteristics of Hmong culture, and gives examples of the problems these differences can create in serving Hmong children and their families.

PIP: Background information is provided to help facilitate the assimilation of the Hmong refugees from Laos into American society. The 100,000 involuntary refugees live primarily in Texas, California, Wisconsin, Minnesota, and Rhode Island, and 66% receive Refugee Cash Assistance or Aid to Families with Dependent Children. Topics covered are 1 the nature and importance of the clan, 2) the centrality of the family and childbearing and discipline, and 3) beliefs about physical and mental illness. The clan, or extended family group, is the basic social and political unit among the Hmong. There are 18 family clans, and all are represented in the US. There is a clan leader who is authorized to represent the clan in working with other clans in the best interests of Hmong society and who has tremendous decision-making power within the group. The clan provides a sense of belonging and helps in group decisions making and problem solving within families. Families are patrilineal, and men are the sole providers while women raise the children and care for the home. Divorce is rare, and if it occurs, the woman must give up her children to the children's fathers clan. Children were considered an economic asset in their rural agrarian life, however, in America, there is the realization that large families are expensive to support. Contraception is resisted. The discipline of children is strict but not abusive by American Standards. Adolescence is a difficult times even for the Hmong and a culture which requires parental presence on a date and views kissing and holding hands in public as inappropriate is in conflict with American culture. The Hmong have coped with the extent of poverty within their ranks. They also value education. The risk factors for assimilation are cultural dissonance and social isolation. Other conflicts with American culture arise in the treatment of disease and the psychological effects of being a minority culture and having lived through a particularly violent time.