Heart Rate During an Exercise Test and Acute High-intensity Interval Training in Type 2 Diabetes.

To describe and compare the acute heart rate changes during an incremental exercise test and high-intensity interval training (HIIT) in subjects of different glucose control. Seventy-five adults were allocated into three groups: Normoglycaemic (NG, n=32), Pre- (PreT2D, n=30) and Type 2 diabetic (T2D, n=13) subjects. Subjects performed an incremental cycling test to determine cardiorespiratory fitness (VO2max), maximum heart rate (HRmax) and HR recovery post maximal effort, as well as a HIIT cycling session. HR variations are reported as HR pre (HR-preINT), and post interval (HR-postINT), percentage of maximum HR (%HRmax), delta of HR increased (∆HRINT), and delta HR recovery after each interval (∆HRR). By groups, there was a significant difference for the %HRmax in 1st and 2nd, but not in intervals 3rd to 10th between Pre-T2D and T2D groups. There were significant differences for the %HRmax in 1st to 2nd intervals between Pre-T2D and T2D groups. Significant (P<0.05) differences at some intervals were found for ΔHRINT, and ΔHRR. These findings suggest that the HR during an incremental exercise test, and from a typical 10-intervals based HIIT protocol could be used as an intensity marker for individuals independent of their glycaemic control.

[Combating tumor cells through SIRT3 activation and exercise]. / Combatiendo el metabolismo de las células cancerosas mediante la activación de SIRT3 y el ejercicio físico.

One of the main features of cancer is the high rate of cell proliferation and growth. To do this, cancer cells need to redirect their metabolism mainly towards anaerobic glycolysis and an increased mitochondrial glutamine energy metabolism. Sirtuins are cellular proteins with regulatory functions on metabolic pathways, genomic stability, apoptosis, longevity, inflammation, energy metabolism and oxidative stress. Sirtuins have emerged recently as a potential therapeutic option to treat several chronic diseases including cancer. This review summarizes the tumor suppressor function of Sirtuin 3 (SIRT3), highlighting its repressor effect on glycolytic metabolism, promoting mitochondrial metabolism and oxidative stress reduction. SIRT3 activation by exercise is particularly described since it may represent a potent tool for several types of cancer treatment.

[Effects of high intensity interval training on blood pressure in hypertensive subjects]. / Entrenamiento interválico de alta intensidad contribuye a la normalización de la hipertensión arterial.

BACKGROUND: Exercise training may reduce blood pressure. AIM: To determine the effects of a high intensity interval training (HIIT) exercise protocol on systolic and diastolic blood pressure in hypertensive subjects. MATERIAL AND METHODS: Eleven men and 27 women aged 46.4 ± 9.8 years were divided in two groups according to their blood pressure. Sixteen were classified as normotensive and 22 as hypertensive. All attended an exercise program with 3 sessions per week for a total of 24 sessions. Each session consisted of one minute of intense exercise performed on a stationary bike, followed by an inactive pause lasting two minutes. This cycle was repeated 10 times and it was thus called 1 * 2 * 10. Blood pressure, weight (kg) and body fat were assessed. RESULTS: In the hypertensive group, there was a significant reduction in systolic blood pressure from 145.4 ± 9.0 to 118.3 ± 15.6 mm Hg (p < 0.05). No significant change was observed in diastolic blood pressure (84.9 ± 3.9 and 85.8 ± 17.6 mmHg. Thus, there was a mean reduction in systolic pressure of 27. 7 ± 18.9 mmHg. Therefore, 73% of patients achieved systolic pressures within normal range, without medication. CONCLUSIONS: The 1 * 2 * 10 exercise method is effective to improve and restore normal blood pressure in persons with hypertension in a period of two months and 24 sessions.

[Effects of 12 sessions of high intensity intermittent training and nutrition counseling on body fat in obese and overweight participants]. / Disminución de la grasa corporal mediante ejercicio físico intermitente de alta intensidad y consejería nutricional en sujetos con sobrepeso u obesidad.

BACKGROUND: The search of efficient exercise alternatives to treat obesity is worthwhile. AIM: To demonstrate the effect of high intensity intermittent exercise on body fat reduction in overweight and obese subjects. MATERIAL AND METHODS: A group of 65 overweight and obese adult subjects (25 men), aged 18-65 years, participated during 12 sessions in a high intensity physical exercise program, 3 days/week. Weight, height and body fat was measured before and after the intervention by bioimpedance. Each session consisted of 1 min stationary cycling exercise at high intensity, followed by 2 min inactive rest. This cycle was repeated 10 times, thus the method is called 1*2*10. RESULTS: There was a significant reduction of body fat of -1.88 ± 2.8 and -3.44 ± 2.7 kg, in women and men, respectively (p < 0.05). CONCLUSIONS: The 1*2*10 training protocol lasting 12 weeks in association with nutrition counseling is effective in reducing body fat in overweight persons.

[Resistance exercise improves serum lipids in adult women]. / Reducción del riesgo cardiovascular en mujeres adultas mediante ejercicio físico de sobrecarga.

BACKGROUND: Sedentariness is one of the main cardiovascular risk factors. Aerobic exercise can reduce the risk; however, resistance training seems to be more effective in reducing cardiovascular risk. AIM: To determine the metabolic effects of a 12 weeks resistance training program of high intensity and low volume in two groups of sedentary adult women. MATERIAL AND METHODS: Forty women aged between 30 and 60 years were randomly assigned to an experimental group and a control group. Four kinds of strength exercises, using their own body weight were chosen. Plasma lipid profile and body composition were measured at baseline and at the end of the intervention. RESULTS: A reduction in total cholesterol and triacylglycerol and an increase in HDL cholesterol was observed in the experimental group after the training program. CONCLUSIONS: The high intensity and low volume training improved plasma lipid profile in this group of women.

[Second Consensus of the Chilean Society of Endocrinology and Diabetes about insulin resistance]. / II Consenso de la Sociedad Chilena de Endocrinología y Diabetes sobre resistencia a la insulina.

Insulin resistance is a prevalent condition commonly associated with unhealthy lifestyles. It affects several metabolic pathways, increasing risk of abnormalities at different organ levels. Thus, diverse medical specialties should be involved in its diagnosis and treatment. With the purpose of unifying criteria about this condition, a scientific-based consensus was elaborated. A questionnaire including the most important topics such as cardio-metabolic risk, non-alcoholic fatty liver disease and polycystic ovary syndrome, was designed and sent to national experts. When no agreement among them was achieved, the Delphi methodology was applied. The main conclusions reached are that clinical findings are critical for the diagnosis of insulin resistance, not being necessary blood testing. Acquisition of a healthy lifestyle is the most important therapeutic tool. Insulin-sensitizing drugs should be prescribed to individuals at high risk of disease according to clinically validated outcomes. There are specific recommendations for pregnant women, children, adolescents and older people.

[High intensity interval training improves glycemic control and aerobic capacity in glucose intolerant patients]. / Ejercicio físico interválico de alta intensidad mejora el control glicémico y la capacidad aeróbica en pacientes con intolerancia a la glucosa.

BACKGROUND: Proper exercise training modifies intra miocellular energy utilization, glucose transport and mitochondrial biogenesis. AIM: To determine the therapeutic effects of a high intensity intermittent training (HIIT) program on glucose homeostasis, physical fitness and body fat in glucose intolerant patients. PATIENTS AND METHODS: Eighteen patients with overweight or obesity and glucose intolerance were invited to participate in an exercise program consisting in three sessions per week for 3 months. Ten participants aged 35 ± 13 years who attended > 26 of the planned 36 sessions, were considered as adherent to exercise. The other eight participants aged 37 ± 17 years, who attended to a mean of 13 sessions, were considered as non-adherent. Both groups had similar body weight, body mass index, body fat, plasma glucose 2 h after an oral glucose load and maximal oxygen uptake. All these variables were measured at the end of exercise intervention. Each session consisted of 1 min exercise of cycling at maximal intensity until muscle fatigue followed by 2 min rest, repeated 10 times. RESULTS: Among adherent participants, twelve weeks of HIIT improved significantly maximal oxygen uptake (6.1 + 3.6 mL/kg/min or 24.6%), reduced 2 h post load blood glucose (-33.7 + 47.9 mg/dL or -12.5%) and body fat (-4.3 + 5.6 kg). No significant changes were observed in the non-adherent group. CONCLUSIONS: HIIT exercise reduces blood glucose after an oral load in glucose intolerant patients.

Emerging and multifaceted potential contributions of polyphenols in the management of type 2 diabetes mellitus.

Type 2 diabetes mellitus (T2DM) is recognized as a serious public health concern with a considerable impact on human life, long-term health expenditures, and substantial health losses. In this context, the use of dietary polyphenols to prevent and manage T2DM is widely documented. These dietary compounds exert their beneficial effects through several actions, including the protection of pancreatic islet ß-cell, the antioxidant capacities of these molecules, their effects on insulin secretion and actions, the regulation of intestinal microbiota, and their contribution to ameliorate diabetic complications, particularly those of vascular origin. In the present review, we intend to highlight these multifaceted actions and the molecular mechanisms by which these plant-derived secondary metabolites exert their beneficial effects on type 2 diabetes patients.

Relationship of adiposity and insulin resistance mediated by inflammation in a group of overweight and obese Chilean adolescents.

The mild chronic inflammatory state associated with obesity may be an important link between adiposity and insulin resistance (IR). In a sample of 137 overweight and obese Chilean adolescents, we assessed associations between high-sensitivity C-reactive protein (hs-CRP), IR and adiposity; explored sex differences; and evaluated whether hs-CRP mediated the relationship between adiposity and IR. Positive relationships between hs-CRP, IR and 2 measures of adiposity were found. Hs-CRP was associated with waist circumference (WC) in boys and fat mass index (FMI) in girls. Using path analysis, we found that hs-CRP mediated the relationship between adiposity (WC and FMI) and the homeostatic model assessment of insulin resistance (HOMA-IR) (p < 0.05) in both sexes. Our novel finding is that inflammation statistically mediated the well described link between increased adiposity and IR.

Increase of plasma fatty acids without changes in n-6/n-3-PUFA ratio in asymptomatic obese subjects.

Obesity is associated with a low grade inflammation which contributes to the development of insulin resistance and diabetes. The aim of this study was to assess the total saturated (SFAs), monounsaturated (MUFAs) and polyunsaturated fatty acids (PUFAs) in plasma from asymptomatic obese subjects and to determine the arachidonic/eicosapentanoic acid ratio [ARA/EPA] as a marker of inflammation, and its eventual association with ultrasensitive CRP. Fourteen obese (34.4 +/- 11.1y.; BMI: 36.0 +/- 4,5 kg/m2) and 12 normal-weight (30.6 +/- 7.8y.; BMI: 23,6 +/- 2,4 kg/m2) subjects were recruited and their plasma fatty acids were determined by gas chromatography. usCRP was higher in the obese subjects (p = 0.01) and correlates with their body fat content. The percentages of SFAs, MUFAs, PUFAs were not affected in the obese subjects but their concentrations were increased, compared with the control group. However, no differences in the long chain PUFAs (DHA and EPA) concentrations or in the plasmatic ARA/EPA ratio were observed in these subjects. These observations do not support a relation between the ARA/EPA ratio and the presence of low grade inflammation evaluated by plasma usCRP in this group of asymptomatic obese subjects.

Effects of Four Lipid Metabolism-Related Polymorphisms on Body Composition Improvements After 12 Weeks of High-Intensity Interval Training and Dietary Energy Restriction in Overweight/Obese Adult Women: A Pilot Study.

Background: Polymorphisms in lipid metabolism-related genes have been associated with obesity and body composition, but these have been scarcely described concerning the magnitude of the response to exercise interventions in the overweight/obese population. Objective: To evaluate the association of perilipin 1 (PLIN1; rs1052700 and rs2304795), lipoprotein lipase (rs283), and adrenoceptor beta 3 (rs4994) polymorphisms with high and low responders (LoRes) to fat mass reduction after 12 weeks of high-intensity interval training (HIIT) and dietary energy restriction in overweight/obese adult women. In addition, we examined the effect of these genetic variants on body composition changes. Methods: Forty-three unrelated overweight/obese adult women were incorporated and genotyped, of which 30 women (age = 27.4 ± 7.9 years; BMI = 29.9 ± 3.3 kg/m2) successfully completed the 12-week supervised HIIT program plus an individually prescribed home hypocaloric diet. Results: An association was observed between the PLIN1 rs1052700 polymorphism with high and LoRes (χ 2 = 8.138; 2 df; p = 0.01). Moreover, after the intervention, the carriers of TT genotype of PLIN1 rs1052700 as compared to AA and AT showed a greater reduction in absolute fat mass (Δ: -5.1 ± 1.8 vs. - 1.8 ± 1.4 vs. - 2.1 ± 2.3 kg; p = 0.04). The effect size of this fat mass reduction between TT and AT genotypes was a mean difference of -3.01 kg [95%IC - 4.88- - 1.1], and between TT and AA genotypes was -3.29 kg [95%IC - 4.86- - 1.65]. No differences were observed for other polymorphisms investigated. Conclusion: These results suggest that the rs1052700 (14995A>T) polymorphism of the PLIN1 gene is associated with a differential response to fat mass reduction after a 12-week intervention in overweight/obese adult women. In addition, women with the TT genotype of this genetic variant showed greater changes in fat mass than AA and AT genotypes. However, further studies are needed to confirm these findings.

Physiological Effects and Inter-Individual Variability to 12 Weeks of High Intensity-Interval Training and Dietary Energy Restriction in Overweight/Obese Adult Women.

Background: Human adaptive response to exercise interventions is often described as group average and SD to represent the typical response for most individuals, but studies reporting individual responses to exercise show a wide range of responses. Objective: To characterize the physiological effects and inter-individual variability on fat mass and other health-related and physical performance outcomes after 12 weeks of high-intensity interval training (HIIT) and dietary energy restriction in overweight/obese adult women. Methods: Thirty untrained adult overweight and obese women (age = 27.4 ± 7.9 years; BMI = 29.9 ± 3.3 kg/m2) successfully completed a 12-week supervised HIIT program and an individually prescribed home hypocaloric diet (75% of daily energy requirements) throughout the whole intervention. High and low responders to the intervention were those individuals who were able to lose ≥ 10 and < 10% of initial absolute fat mass (i.e., kilograms), respectively. Results: The prevalence for high and low responders was 33% (n = 11) and 66% (n = 19), respectively. At the whole group level, the intervention was effective to reduce the absolute fat mass (30.9 ± 7.2 vs. 28.5 ± 7.2 kg; p < 0.0001), body fat percentage (39.8 ± 4.3 vs. 37.8 ± 4.9%; p < 0.0001), and total body mass (76.7 ± 10.1 vs. 74.4 ± 9.9 kg; p < 0.0001). In addition, there were improvements in systolic blood pressure (SBP; Δ% = -5.1%), diastolic blood pressure (DBP; Δ% = -6.4%), absolute VO2peak (Δ% = +14.0%), relative VO2peak (Δ% = +13.8%), peak power output (PPO; Δ% = +19.8%), anaerobic threshold (AT; Δ% = +16.7%), maximal ventilation (VE; Δ% = +14.1%), and peak oxygen pulse (O2 pulse; Δ% = +10.4%). However, at the individual level, a wide range of effects were appreciated on all variables, and the magnitude of the fat mass changes did not correlate with baseline body mass or fat mass. Conclusion: A 12-week supervised HIIT program added to a slight dietary energy restriction effectively improved fat mass, body mass, blood pressure, and cardiorespiratory fitness (CRF). However, a wide range of inter-individual variability was observed in the adaptative response to the intervention. Furthermore, subjects classified as low responders for fat mass reduction could be high responders (HiRes) in many other health-related and physical performance outcomes. Thus, the beneficial effects of exercise in obese and overweight women go further beyond the adaptive response to a single outcome variable such as fat mass or total body mass reduction.

Anesthesiology Handoff Simulation Case: A Handoff From Intensive Care Unit to Operating Room for Anesthesiology Learners.

Introduction: Handoffs have been shown to be a potential cause of communication failures, leading to possible inefficiencies and patient harm. We noticed that our CA-1 residents were struggling with patient handoffs and designed this simulation to improve their handoff skills. Methods: This anesthesiology-specific simulation introduced learners to the perioperative handoff process. We designed it for anesthesiology learners, including junior residents, medical students, and student nurse anesthetists. The simulation centered upon an anesthesiology resident taking care of an ICU patient and handing that patient off to another anesthesiology provider, who took the patient to the OR. We charged learners with reviewing the patient's history and hospital course and giving a complete handoff. We evaluated learners on the completeness and quality of the handoff, as well as on their performance during the session. Results: Twenty-seven learners participated in this handoff simulation. The participants reported that the simulation improved their understanding of the anesthetic implications of medical conditions and gave them a better understanding of the essential elements of a handoff. Learners also indicated that the debriefing portion of the simulation was effective in filling some of their medical knowledge gaps and improving their handoff skills. Discussion: This simulation was found to be an effective educational experience for our CA-1 and CA-3 residents, medical students, and student nurse anesthetists. Feedback was positive from all learners. As a result, this simulation will be implemented in the early learning curriculum for all of our CA-1 residents.

Effect of the dietary fat quality on insulin sensitivity.

Recent evidence shows that specific fatty acids affect cell metabolism, modifying the balance between fatty acid oxidation and lipogenesis. These effects may have important implications in addressing the present epidemic of nutrition-related chronic disease. Intake of dietary saturated and n-6 PUFA have increased while n-3 fatty acid intake has decreased. Obesity, type 2 diabetes and insulin resistance are highly prevalent, and both are strongly related to disorders of lipid metabolism characterized by an increased plasma and intracellular fatty acid availability. Thus, it has been hypothesized that change in the quality of dietary fat supply is able to modify the degree of insulin sensitivity. Animal studies provide support for this notion. However, there is limited human data either from normal or diabetic subjects. This review aims to analyse human studies that address this question. To this purpose, the experimental design, dietary compliance, insulin-sensitivity method used and confounding variables are discussed in order to identify the role of dietary fat quality as a risk factor for insulin resistance. Most studies (twelve of fifteen) found no effect relating to fat quality on insulin sensitivity. However, multiple study design flaws limit the validity of this conclusion. In contrast, one of the better designed studies found that consumption of a high-saturated-fat diet decreased insulin sensitivity in comparison to a high-monounsaturated-fat diet. We conclude that the role of dietary fat quality on insulin sensitivity in human subjects should be further studied, using experimental designs that address the limitations of existing data sets.

Plasma arachidonic acid influences insulin-stimulated glucose uptake in healthy adult women.

BACKGROUND: Fatty acids can modulate lipid metabolism, this is related to insulin resistance (IR). This study evaluated the relationship of plasma fatty acid profile with IR, fuel oxidative metabolism and plasma lipid concentration in 'healthy' women. METHODS: Sixteen 'healthy', sedentary and non-obese women were evaluated under fasting conditions for fuel oxidation, plasma fatty acid profile, free fatty acids, triglycerides, glucose and insulin concentrations. IR, fuel oxidation and plasma lipids were measured under insulin-stimulated conditions. Using the Spearman test the correlation between relevant variables was assessed. Stepwise multiple regression analysis was done to identify the main clinical/metabolic and fatty acid determinants of IR. RESULTS: Plasma arachidonic acid content (%) determined IR, and in combination with insulin-stimulated plasma triglyceride concentration explained 45% of the IR variance. IR was inversely related to physical fitness (rs = -0.48, p = 0.01). The latter was inversely associated to plasma saturated fatty acid content (%) (rs = -0.48, p < 0.01), but directly associated to plasma docosahexaenoic acid content (%) (rs = 0.40, p = 0.04). CONCLUSIONS: Support for the hypothesis that specific fatty acids influence IR is provided. Plasma arachidonic acid was associated to IR, independent on clinical/metabolic study variables. Docosahexaenoic and saturated fatty acids could potentially affect insulin action through modulating mitochondrial oxidative function.

[Physical fitness and insulin sensitivity in a group of obese children from 8 to 13 years of age by puberal state]. / Condición física y sensibilidad insulínica en un grupo de escolares obesos de 8 a 13 años según estado puberal.

INTRODUCTION: Insulin resistance is the most common metabolic disorder associated with obesity and highest cardiometabolic risk in children. If the inadequate physical condition is added, they have a high risk of developing cardiometabolic complications at an early age. OBJECTIVE: To evaluate physical fitness and insulin sensitivity in obese school children of 8-13 years of age from three public schools in the Metropolitan Region of Santiago. METHODS: the study was carried out in 61 obese school children (25 Tanner I-II y 36 Tanner III-V). Anthropometric measures, Tanner stages, body composition (using 4-compartment model), physical fitness with the six-minute test and laboratory indicators, glucose, insulin and HOMA-IR, were measured. Metabolic syndrome was diagnosed according to the criteria of Cook. RESULTS: Obese prepubertal and pubertal children and adolescents showed inadequate physical fitness, refl ected in the distance and heart rate during and after the six-minute test. In turn, the sample has a high prevalence of insulin resistance in conjunction with metabolic syndrome. CONCLUSIONS: Regardless of the pubertal status, obese schoolchildren have a poor physical fitness and decreased insulin sensitivity reflected in a compensatory hyperinsulinemia.

INTRODUCCIÓN: la resistencia a la insulina es la alteración metabólica más común relacionada con la obesidad y se asocia a un mayor riesgo cardiovascular en la edad pediátrica. Si a esto se suma una inadecuada condición física, existe un alto riesgo de desarrollar complicaciones cardiometabólicas tempranamente. OBJETIVO: evaluar la condición física y la resistencia insulínica en escolares obesos de 8 a 13 años de edad, seleccionados en tres establecimientos públicos de la Región Metropolitana de Santiago. MÉTODOS: el estudio se llevó a cabo en 61 escolares obesos (25 Tanner I-II y 36 Tanner III-V). Se realizaron mediciones antropométricas, etapas de Tanner, composición corporal con el modelo de cuatro compartimentos, condición física con el test de seis minutos (TM6min) e indicadores de laboratorio, glicemia, insulinemia y HOMA-IR. Se diagnosticó síndrome metabólico según criterio de Cook.RESULTADOS: los escolares y adolescentes obesos prepúberes y púberes presentan una inadecuada condición física, reflejada en la distancia recorrida y en la frecuencia cardiaca durante y posterior al TM6min. A su vez, la muestra presenta una alta prevalencia de resistencia a insulina en conjunto con síndrome metabólico. CONCLUSIONES: independientemente del estado puberal, los escolares obesos presentan una baja condición física y una disminución de la sensibilidad a la insulina, que se refleja en un hiperinsulinismo compensatorio.

Acute effect of meal glycemic index and glycemic load on blood glucose and insulin responses in humans.

OBJECTIVE: Foods with contrasting glycemic index when incorporated into a meal, are able to differentially modify glycemia and insulinemia. However, little is known about whether this is dependent on the size of the meal. The purposes of this study were: i) to determine if the differential impact on blood glucose and insulin responses induced by contrasting GI foods is similar when provided in meals of different sizes, and; ii) to determine the relationship between the total meal glycemic load and the observed serum glucose and insulin responses. METHODS: Twelve obese women (BMI 33.7 +/- 2.4 kg/m2) were recruited. Subjects received 4 different meals in random order. Two meals had a low glycemic index (40-43%) and two had a high-glycemic index (86-91%). Both meal types were given as two meal sizes with energy supply corresponding to 23% and 49% of predicted basal metabolic rate. Thus, meals with three different glycemic loads (95, 45-48 and 22 g) were administered. Blood samples were taken before and after each meal to determine glucose, free-fatty acids, insulin and glucagon concentrations over a 5-h period. RESULTS: An almost 2-fold higher serum glucose and insulin incremental area under the curve (AUC) over 2 h for the high- versus low-glycemic index same sized meals was observed (p < 0.05), however, for the serum glucose response in small meals this was not significant (p = 0.38). Calculated meal glycemic load was associated with 2 and 5 h serum glucose (r = 0.58, p < 0.01) and insulin (r = 0.54, p < 0.01) incremental and total AUC. In fact, when comparing the two meals with similar glycemic load but differing carbohydrate amount and type, very similar serum glucose and insulin responses were found. No differences were observed for serum free-fatty acids and glucagon profile in response to meal glycemic index. CONCLUSION: This study showed that foods of contrasting glycemic index induced a proportionally comparable difference in serum insulin response when provided in both small and large meals. The same was true for the serum glucose response but only in large meals. Glycemic load was useful in predicting the acute impact on blood glucose and insulin responses within the context of mixed meals.

Comparison of body fat calculations by sex and puberty status in obese schoolchildren using two and four compartment body composition models.

INTRODUCTION: Determine body composition changes in adiposity can assess an individual. OBJECTIVE: The objective of this study was to evaluate total body fat percentage based on two and four compartment models in obese Chilean school children, adjusting for differences in sex and puberty status. METHODS: Sixty-one obese school children (33 boys and 28 girls) between 8 and 13 years of age were evaluated. Two compartment measurements of body fat percentage considered isotope dilution, plethysmography, radiographic absorptiometry and bioelectrical impedance; using the four compartment model as a benchmark. RESULTS: Each method explained between 43-87% of the variance in body fat percentage in Tanner stage I and II children and between 78-96% in Tanner stage III and V children. In both groups of children methods differed significantly for stage I, with the exception of plethysmography. High R2 values were observed for girls in all Tanner stages. Each method explained between 34-92% of the variance in body fat percentage for girls in stages I and II and between 63-93% for stages III and V. In obese boys, R2 values were high for stages III and V. In girls and boys in Tanner stage III and V, the smallest differences were observed for isotopic dilution, and DXA (dual-energy X-ray absorptiometry) scan for stages I and II. CONCLUSIONS: For obese boys and girls, the two compartment model with isotopic dilution and DXA had the best precision and smallest differences in determining body fat percentage compared to the benchmark.

Energy expenditure, nutrition status, and body composition in children with cystic fibrosis.

OBJECTIVE: Undernutrition is a frequent complication in patients with cystic fibrosis (CF). Elevated energy requirements have been found to be 4% to 33% higher than in controls in some studies. Whether or not this is caused by a primary defect or energy metabolism is still a matter of controversy. To this end, we assessed energy expenditure, nutrition status, and body composition of clinically stable CF outpatients. METHODS: Fifteen clinically stable CF patients, ages 2 to 15 y, were paired with 15 healthy control children. Measurements consisted of anthropometry and body composition. Plasma tocopherol, retinol, and hair zinc content were measured. Resting energy expenditure was determined by indirect calorimetry. Physical activity and dietary intake were recorded by recall methods. RESULTS: Two children were nutritionally at risk according to the weight/height index, eight were normal, three were overweight, and two were obese. Body composition was similar in both groups. Zinc, tocopherol, and retinol levels were low in three, two, and three patients, respectively. Resting energy expenditures were 4.7 MJ/d (1127 +/- 220 kcal/d) in CF children and 4.63 MJ/d (1108 +/- 191 kcal/d) in control children (P = not significant). Physical activity level was sedentary in 86.6% of CF patients; the rest had a light physical activity pattern. Energy intake represented 141% of the estimated daily energy expenditure. CONCLUSIONS: Non-oxygen-dependent CF children, without acute respiratory infection, had resting energy expenditures comparable to those of matched controls. Total energy expenditure was similar to or slightly lower than that in healthy children. Dietary recommendations for CF patients need to be reassessed.

Body composition estimates using different measurement techniques in a sample of highland subsistence farmers in Guatemala.

This study aims at assessing the accuracy of estimates of body composition provided by bioimpedance (BIA) equations developed for U.S. populations when applied to a sample of Guatemalan farmers. If these equations were shown to have low validity, the second objective was to develop more accurate estimates of fat-free mass (FFM). One hundred males and females 19 to 45 years of age were randomly selected from four rural communities in the Western Highlands of Guatemala. Bioimpedance equations explained 59 and 33% of the variation in FFM, with a RMSE of 2.7 and 2.8 kg in males and females, respectively. Body fat (BF) predictions had a lower R2 . Using the "all possible regressions" procedure, the best subset for prediction of FFM used anthropometric and BIA variables as predictors. The best model for men and women included only anthropometric variables: 75% of the variance in FFM for men and 70% of the variance in women was explained by this model. The RMSE was 2.1 and 1.9 kg for both groups, respectively. It is concluded that FFM can be estimated from anthropometric dimensions with a high degree of accuracy and use of BIA does not provide more valid estimates.