Flávia Meyer

Childhood obesity: towards effectiveness

OBJECTIVEnTo review therapeutic approaches to childhood obesity and also its diagnosis and prevention.nnnSOURCES OF DATAnSearches were performed of scientific papers held on the MEDLINE, Ovid, Highwire and Scielo databases. Keywords utilized were: childhood, obesity and a variety of combinations of this term with treatment, prevention and consequence. The search returned papers including review articles, observational studies, clinical trials and consensus statements. Bibliographical references in these articles were also investigated if it was perceived that they were relevant. Data was collected from 1998 to 2003.nnnSUMMARY OF THE FINDINGSnWhile a number of different Brazilian prevalence studies were found, few gave details of the results of educational programs in our country.nnnCONCLUSIONSnChildhood obesity must be prevented through prescriptive diets from birth throughout childhood. Educational programs that might be applicable to primary health care or schools should receive further study.

Nutrition for the young athlete

Abstract Athletics is a popular sport among young people. To maintain health and optimize growth and athletic performance, young athletes need to consume an appropriate diet. Unfortunately, the dietary intake of many young athletes follows population trends rather than public health or sports nutrition recommendations. To optimize performance in some disciplines, young athletes may strive to achieve a lower body weight or body fat content and this may increase their risk for delayed growth and maturation, amenorrhoea, reduced bone density, and eating disorders. Although many of the sports nutrition principles identified for adults are similar to those for young athletes, there are some important differences. These include a higher metabolic cost of locomotion and preferential fat oxidation in young athletes during exercise. Young athletes, particularity children, are at a thermoregulatory disadvantage due to a higher surface area to weight ratio, a slower acclimatization, and lower sweating rate. An appropriate dietary intake rather than use of supplements (except when clinically indicated) is recommended to ensure young athletes participate fully and safely in athletics.

Atendimento ambulatorial individualizado versus programa de educação em grupo: qual oferece mais mudança de hábitos alimentares e de atividade física em crianças obesas?

OBJECTIVE: To compare two strategies for childhood obesity management: ambulatory assistance (individual) and educational program (in group). METHOD: Children and adolescents from 7 to 13 years of age were selected at random. They were divided into two groups: individually assisted or assisted in groups. An educational program about childhood obesity was created, with monthly meetings that consisted of lectures with parents participation and group work. Simultaneously, children and teenagers of the other group received individual ambulatory assistance. The program took place for six months. Body complexion, eating habits and physical activities were assessed before and after interventions. RESULTS: The sample comprised 38 children and adolescents whose mean age was 9.9 years old. The program was more effective in increasing physical activity (P=0,003), specially walking (p = 0.003), as well as in reducing total cholesterol (p = 0.038). Reduction of body mass index, obesity index and caloric intake was similar in both groups. As for food habits, ambulatory assistance increased the intake of fruits (p = 0.033) and vegetables (p = 0.002) and reduced the amount of French fries and crisps (p = 0.041), while children participating in the program reduced the intake of soft drinks (p = 0.022), sandwiches, pizza and fast food (p = 0.006). CONCLUSIONS: Both strategies for handling childhood obesity were favorable to changes in food and physical activity habits. Group assistance was as effective as the individual assistance, consolidating as an alternative for the obesity treatment.

Responses of Obese and Lean Girls Exercising under Heat and Thermoneutral Conditions

OBJECTIVEnTo compare thermoregulatory and perceptual responses between lean and obese girls during and after exercise under heat (HC) and thermoneutral (TC) conditions.nnnSTUDY DESIGNnIn a randomized order, 27 girls (14 lean [16.6 ± 6.7% fat and 9.1 ± 1.3 years] and 13 obese [41.3 ± 6.7% fat and 9.4 ± 1.1 years]) cycled 30 minutes at ~55% peak oxygen uptake in 2 sessions, which only differed in the thermal conditions (35 °C and 40% relative humidity vs 24 °C and 50% relative humidity).nnnRESULTSnInitial rectal temperature (T(re)) was higher in obese versus lean during HC (37.5 ± 0.3 °C vs 37.3 ± 0.3 °C, P = .03) and TC (37.6 ± 0.3 °C vs 37.3 ± 0.2 °C; P = .03) sessions. During cycling, Tre remained higher in the obese, but the rate of increase was greater in the lean. This change occurred mainly in the HC, when final Tre of the lean surpassed that of the obese (37.8 ± 0.2 vs 38.0 ± 0.2 °C, P = .04). Sweat volume (in mL · m(-2)) was similar between lean and obese in the HC (167 ± 119 and 120 ± 145) and TC (200 ± 196 vs 72 ± 20). Heart rate, rate of perceived exertion, and thermal sensation were similar between groups, independent of the thermal condition. Cycling in HC produced decreased thermal comfort (P = .009) and increased irritation (P = .02) within the lean girls.nnnCONCLUSIONnThermoregulatory and perceptual responses of prepubescent obese girls during 30 minutes of cycling at a similar relative intensity do not seem to be impaired when comparing with a lean group either in TC or HC.

Força muscular de atletas de voleibol de 9 a 18 anos através da dinamometria computadorizada

El objetivo de este estudio fue describir y comparar las fuerzas musculares isometrica e isocinetica en diferentes grados maduracionales de ninos y ninas atletas de voleibol. Participo del estudio un total de 66 ninos y adolescentes, en tratamiento deportivo competitivo. De los 37 ninos, 10 eran pre-puberes (PP), 15 puberes (PU) y 12 post-puberes (PO). De las 29 ninas, 11 eran PP, 13 PU e 5 PO. Fue utilizado un dinamometro computarizado (Cybex Norm) para medir la fuerza isocinetica de flexion de codo (FC) y extension de rodilla (EJ) en las velocidades de 60 y 90o.s-1. La fuerza isometrica fue medida en los mismos ejercicios en los angulos de 60 y 90o (FC), y 45 y 60o (EJ). Se utilizo la ANOVA para comparaciones entre los generos y grados maduracionales y el test post hoc de Tuckey. El nivel de significancia considerado fue de p < 0,05. Entre los grados maduracionales los grupos mas viejos fueron siempre mas fuertes que los de los mas jovenes tanto para el genero masculino como para el femenino. Entre los sexos, los ninos fueron mas fuertes que las ninas apenas en el grupo PO en los dos angulos de los tests isometricos de FC y en el test isocinetico en 90os-1. En los tests isometricos de EJ los valores no fueron significativamente diferentes para ninos y ninas independientemente do grado de maturacion. En los test isocineticos, los ninos fueron mas fuertes que las ninas en los grupos PP e PO, en 60 e 90o.s-1. Esos resultados sugieren que el grado maturacional es un mayor determinante de la fuerza muscular en jovenes atletas de voleibol que el sexo.

Run performance of middle-aged and young adult runners in the heat.

The aging process may impair exercise tolerance in the heat. It is not clear whether this impairment is partly due to a reduction in aerobic capacity. To compare the exercise performance and thermoregulatory responses of middle-aged and young adults with similar aerobic capacities and training statuses, 7 middle-aged (54±2 years; 58±4 ml·kgu2009-u20091·minu2009-u20091) and 7 young (28±1 years; 61±5u2009ml·kgu2009-u20091·minu2009-u20091) male competitive endurance runners underwent 2 10-km self-paced and 2 fixed-workload (90% of race speed) runs until fatigue on a treadmill in hot (40°C) and moderate (20°C) environments on separate days. The runners total time, average speed, rectal temperature, heat storage rate, physiological strain index, sweat rate, sweat sensitivity, number of heat-activated sweat glands and sweat rate per sweat gland were measured or calculated. Body fat, body surface area, body surface area per body mass, training volume and VO2max were similar between the 2 groups. No differences were observed in total time (59±3; 49±3; 27±2; 54±5 min in the middle-aged and 60±2; 49±3; 27±2; 51±4 min in the young group), average speed, rectal temperature, heat storage rate, physiological strain index, sweat rate (17±7; 15±3; 23±7; 13±2 g.mu2009-u20092.minu2009-u20091 in the middle-aged and 20±5; 14±4; 22±5; 15±4 g.mu2009-u20092.minu2009-u20091 in the young group) or sweat sensitivity between age groups (p>0.05) in any trial. The number of heat-activated sweat glands (88±14; 80±18; 90±16; 66±14 cmu2009-u20092 in the middle-aged and 43±10; 32±10; 37±11; 31±11 cmu2009-u20092 in the young group) was higher, and the sweat rate per sweat gland was smaller, in the middle-aged than the young group (p<0.05) in all of the trials. We conclude that running performance and body thermoregulation are similar between young and middle-aged runners with similar aerobic capacities and training statuses under hot and moderate conditions in self-paced and fixed-intensity runs. The decrease observed in the sweat rate per sweat gland in middle-aged men was compensated for by a higher number of heat-activated sweat glands.

Fluid Balance and Dehydration in the Young Athlete Assessment Considerations and Effects on Health and Performance

Many young athletes train and compete under conditions that put their body fluid balance at risk, and hypohydration is usually the major concern. Another less frequent condition is hyperhydration that—if accompanied by other risk factors—may cause hyponatremia. Water and electrolyte losses during physical activities occur primarily from sweat. Such losses have been identified mostly in active (but nonathletic) young populations under laboratory settings. Studies have been trying to estimate fluid losses in the athletic population under field conditions, taking into account the sport modality and environmental conditions. Besides these external conditions, young athletes adopt different drinking attitudes, which may depend on knowledge, education, and the opportunities to drink during the break periods as well as fluid availability. Focusing on the young athlete, this review will discuss water and sodium losses from sweat, the effects of hypohydration on performance, and fluid intake attitudes within and during practices and competitions. Some considerations related to the methods of identifying hydration status and guidelines are also given, with the understanding that they should be individually adapted for the athlete and activity. The young athlete, parents, coaches, and athletic/health professionals should be aware of such information to prevent fluid imbalances and the consequent hazardous effects on performance and health.

Avaliação antropométrica e da força muscular em nadadores pré-púberes e púberes

Anthropometric and muscle strength evaluation in prepubescent and pubescent swimmers and muscle strength and body compo- sition are important for a better sporting performance. The objec- tive of this study was to describe and to compare anthropometri- cal and muscle strength aspects of prepubescent and pubescent swimmer boys and girls. Forty-eight healthy competitive swimmers participated in this study. Among them, 11 boys were prepubes- cent (PP) and 16 were pubescent (PU) and 8 girls were PP and 13 PU. The anthropometrical data studied were body weight, stature, skinfolds and circumferences. A computerized dynamometer (Cy- bex Norm) was used to isokinetic (60 and 90o.s-1) and isometric strength measurements (45 and 60o) of knee extension (KE) and isokinetic (60 and 90o.s-1) and isometric (60 and 90o) strength of elbow flexion (EF). There were no differences between PP boys and girls in muscle strength. In PU group, the boys were stronger than girls in all KE and EF tests. This difference was shown in al- most all tests when adjusted by body weight (except in KE isomet- ric tests, where values were similar between boys and girls). PU boys and girls were stronger than PP in all tests and this difference was shown in almost all tests, when adjusted by body weight (ex- cept in KE isometric tests, where PU and PP girls were not differ- ent). These results show the anthropometrical and muscle strength pattern in swimmer children and adolescents.

Responses of obese and non-obese boys cycling in the heat.

This study compared rectal temperature (Tre), heat sensation and sweating between obese and non-obese boys during cycling in the heat. Participants (aged 12-15 years) were 17 obese and 16 non-obese (BMI=29.4±4.3 and 16.8±1.7 kg · m⁻², respectively) boys. They cycled for 30-min (50-55% VO(2peak)) in a climatic chamber (35°C, 45% RH) and Tre, heat sensation and sweat volume were monitored. From the start to the end of cycling, Tre was similar between the obese (37.4±0.3-37.8±0.3°C) and non-obese (37.3±0.2-37.9±0.2°C) groups. Heat sensation was higher in the obese group from the start (3.6±2.7 vs. 1.3±1.4 cm; P=0.008) to the end (7.6±2 vs. 5.2±2.2 cm; P=0.003) of cycling. Sweat volume corrected by body surface area was similar between the obese (200±123 mL · m⁻²) and non-obese (212±80 mL · m⁻²) groups. Initial and final HR were similar in both groups, and RPE was higher in the obese group at 25th (P=0.040) and 30th (P=0.019) min. In conclusion, the obese pubescent participants presented similar Tre and sweating volume, but higher heat sensation while cycling in the heat.

Dinamometria computadorizada como metodologia de avaliação da força muscular de meninos e meninas em diferentes estágios de maturidade

O objetivo deste estudo foi descrever e comparar a forca muscular isometrica e isocinetica em meninos e meninas de diferentes graus maturacionais. Participaram do estudo um total de 57 criancas e adolescentes saudaveis, caucasianos e nao-atletas. Dos 28 meninos, 11 eram pre-puberes (PP), sete puberes (PU) e dez pos-puberes (PO). Das 29 meninas, 10 eram (PP), nove PU e 10 PO. Foi utilizado um dinamometro computadorizado (Cybex Norm) para medir a forca isometrica de flexao do cotovelo (FC) nos ângulos de 60 e 90 graus de extensao do joelho (EJ) em 45 e 60 graus. A forca isocinetica foi medida nos mesmos exercicios nas velocidades de 60 e 90 graus. Utilizou-se a analise de variância (ANOVA), usando dois fatores (genero e maturacao) para comparacoes, considerando-se p