We analyzed heart rate (HR), systolic and diastolic blood pressure (SBP, DBP), oxygen consumption, and carbon dioxide production in 17 male adolescents during a racing simulation video game (VG) and compared to resting state (RS) and exercise testing (ET) measures. We were able to demonstrate a significant (p<.005) increase from RS to VG concerning HR (+13.1 bpm), SBP (+20.8 mmHg), and DBP (+12.1 mmHg) with SBP and DBP elevations exceeding 2 SD in all children and 14/17 children, respectively. The energy consumption during VG (max 1.71 kcal/min) was unaltered compared to RS and significantly lower compared to ET even at the starting strain of 25 W (1.94 kcal/min). Hemodynamic parameters tested demonstrated lower HR, unchanged SBP, and higher DBP during the VG compared with ET. Comparing all measured parameters it can be said that the relation of blood pressure and energy consumption during VG might not be favorable. Copyright \copyright2007 Society for Psychophysiological Research. Read more...

Purpose. To examine sedentary behaviours (including television viewing, playing computer games and computer use), diet, exercise and fitness in relation to overweight/obesity in Australian adolescents. Methods. Questionnaires elicited food frequency data, time spent in TV viewing, using computers, other sedentary occupations and physical activity recall. Weight, height and fitness (laps completed in the Leger test) were measured. Results. Among 281 boys and 321 girls, mean age 12 years (SD 0.9), 56 boys (20.0%) and 70 girls (23.3%) were overweight/obese. Greater fitness was associated with decreased risk of overweight/obesity in boys (Odds ratio [OR] 0.74; 95% CI 0.55, 0.99) and girls (OR 0.93; 95% CI 0.91, 0.99). TV-viewing predicted increased risk in boys (OR 1.04; 95'% CI 1.01, 1.06) and decreased risk in girls (OR 0.99; 95% CI 0.96, 0.99). Computer use, video games, and other sedentary behaviours were not significantly related to risk of overweight/obesity. Vegetable intake was associated with lower risk in boys (OR 0.98; 95% CI 0.97, 0.99); greater risk was associated with lower fat intake in boys and girls, lower consumption of energy-dense snacks in boys (OR 0.74; 95% CI 0.62, 0.88) and greater intake of vegetables in girls (OR 1.02; 95% CI 1.00, 1.03), suggesting dieting or knowledge of favourable dietary choices in overweight/obese children. Conclusions. Among these adolescents, fitness was negatively related to risk for overweight/obesity in boys and girls. TV-viewing was a positive predictor in boys and a negative predictor in girls but the effect size was small; other sedentary behaviours did not predict risk. Read more...

OBJECTIVE. We examined the effect of activity-enhancing screen devices on children's energy expenditure compared with performing the same activities while seated. Our hypothesis was that energy expenditure would be significantly greater when children played activity-promoting video games, compared with sedentary video games.METHODS. Energy expenditure was measured for 25 children aged 8 to 12 years, 15 of whom were lean, while they were watching television seated, playing a traditional video game seated, watching television while walking on a treadmill at 1.5 miles per hour, and playing activity-promoting video games.RESULTS. Watching television and playing video games while seated increased energy expenditure by 20 +/- 13% and 22 +/- 12% above resting values, respectively. When subjects were walking on the treadmill and watching television, energy expenditure increased by 138 +/- 40% over resting values. For the activity-promoting video games, energy expenditure increased by 108 +/- 40% with the EyeToy (Sony Computer Entertainment) and by 172 +/- 68% with Dance Dance Revolution Ultramix 2 (Konami Digital Entertainment).CONCLUSIONS. Energy expenditure more than doubles when sedentary screen time is converted to active screen time. Such interventions might be considered for obesity prevention and treatment. Read more...

Objective: To assess developmental trends in physical activity and sedentary behaviour in British adolescents in relation to sex, ethnicity and socioeconomic status (SES).Design: A 5-year longitudinal study of a diverse cohort of students aged 11 - 12 years at baseline in 1999.Setting: 36 London schools sampled using a stratified random sampling procedure.Participants: A total of 5863 students categorised as white, black or Asian, and stratified for SES using the Townsend Index.Main outcome measures: Number of days per week of vigorous activity leading to sweating and breathing hard. Hours of sedentary behaviour, including watching television and playing video games. Data were analysed using multilevel, linear, mixed models.Results: Marked reductions in physical activity and increases in sedentary behaviour were noticed between ages 11 - 12 and 15 - 16 years. Boys were more active than girls, and the decline in physical activity was greater in girls (46% reduction) than in boys (23%). Asian students were less active than whites, and this was also true of black girls but not boys. Black students were more sedentary than white students. Levels of sedentary behaviour were greater in respondents from lower SES. Most differences between ethnic and SES groups were present at age 11 years, and did not evolve over the teenage years.Conclusions: Physical activity declines and sedentary behaviour becomes more common during adolescence. Ethnic and SES differences are observed in physical activity and sedentary behaviour in British youth that anticipate adult variations in adiposity and cardiovascular disease risk. These are largely established by age 11 - 12 years, so reversing these patterns requires earlier intervention. Read more...

Associations between demographic characteristics, school schedules, activity choices, family functioning, and sleep behaviors were estimated using, nationally representative time-diary data from 2,454 children (ages 5.5 to 11.9 years) and adolescents (ages 12.0 to 19.1 years). For weekdays, African American adolescents, Asian children, and those with earlier school start times and longer travel times to school reported fewer sleep hours. More time spent watching television (for children), doing homework (for adolescents), and engaging in religious activities predicted fewer hours, whereas a longer time spent on meals predicted greater hours of weekday sleep. For younger children, greater parental warmth predicted more hours of weekday sleep, whereas for adolescents, stricter household rules were protective. On weekends, African American adolescents and Hispanic children slept less, and there were strong effects of activity choices including time spent on television, computer and video-games, sports, religious activities, socializing, and employment. In accounting for age-related decreases in sleep hours from childhood to adolescence, earlier school start times, greater hours of homework, greater paid employment, less time spent on meals, and fewer household rules were all significant mediators. Read more...

The purpose of this systematic review was to (i) estimate the prevalence and dose of television (TV) viewing, video game playing and computer use, and (ii) assess age-related and (iii) secular trends in TV viewing among youth (<= 18 yr). Ninety studies published in English language journals between 1949 and 2004 were included, presenting data from 539 independent samples (the unit of analysis). Results suggest contemporary youth watch on average 1.8-2.8 h of TV per day, depending on age and gender. Most (66%) are 'low users' (< 2 h day(-1)) of TV but 28% watch more than 4 h day(-1). Boys and girls with access to video games spend approximately 60 and 23 min day(-1), respectively, using this technology. Computer use accounts for an additional 30 min day(-1). Age-specific data suggest TV viewing decreases during adolescence, but those considered 'high users' at young ages are likely to remain high users when older. For children with access to a television set, the number of hours spent viewing does not appear to have increased over the past 50 years. Read more...

Purpose: To describe longitudinal changes in leisure-time sedentary behavior among girls, during early to mid-adolescence. Methods: A 2.5-year prospective cohort study, comprising 5 data collections, 6 months apart, between 2000 and 2002. Girls aged 12-15 years (n = 200) from 8 high schools located in Sydney, Australia, self-reported the usual time spent each week in a comprehensive range of sedentary behaviors. Results: Retention rate for the study was 82%. Girls aged 12.8 years spent approximately 45% of their discretionary time in sedentary behavior, which increased to 63% at age 14.9 years. Watching TV, videos, and playing video games (small screen recreation; SSR) was the most popular sedentary pastime, accounting for 33% of time spent in sedentariness, followed by homework and reading (25%). Sedentary behavior increased 1.4 and 3.3 hours on week and weekend days, respectively. On weekdays, increased time was spent on hobbies (27 min/day) and on weekend days, increased time was spent sitting around talking with friends (60 min/day), computer use (37 min/day), and television viewing (34 min/day). Conclusions: Among girls, the transition between early and mid-adolescence was accompanied by a significant increase in leisure-time sedentary behavior. Interventions to reduce sedentariness among adolescent girls are best to focus on weekend behaviors. Studies seeking to examine the association between inactivity and the development of chronic health problems need to examine a diverse range of activities that comprehensively measure sedentariness. This information will provide a better understanding of inactivity patterns among adolescent girls. Read more...

Objectives: Regular physical activity (PA) in young needs to be promoted to prevent obesity and subsequent diabetes. Influences of parental PA on adolescents' activity level have been studied with discordant results and the effect of socioeconomic status (SES) on these relationships is not clarified. Methods: Cross-sectional population-based survey of about 3000 12-year old French students and their parents. Familial associations were assessed with logistic regression models taking into account SES and children's and parents' corpulence. Sport involvement and sedentary behaviors were assessed by standardized questionnaires filled out separately by children and parents, the latter also reporting their educational data and family income tax. Results: Participation in structured PA outside school was higher for boys (74%) than for girls (58%, p<10(-5)) and a high sedentary behavior (watching television, playing computer/video games and reading greater than or equal to2h/day) was observed in one-third of the sample, both in boys and in girls. Children were more likely to participate in structured PA outside school when both parents practiced sport as compared to neither parent practicing it, with an odd ratio OR (95%Cl) of 1.97 (1.4-2.8) for boys and 1.56 (1.2-2.1) for girls. Familial associations of inactivity were significant for boys only. A greater percentage of adolescents had a high level of sedentary behavior when both parents versus no parents watched television >2h/day (OR 1.95 (1.5-2.6)). Parent-child physical activity relationships were not modified by the family SES or the children's or parents' weight status. Conclusion: Parental involvement in sport is an important correlate of a young adolescent's participation in structured PA outside school, whatever the family SES or corpulence of the family members. Read more...

Objective: To examine patterns of inactivity and snacking and their relationship with overweight status in Chinese children. Research Methods and Procedures: The study population was drawn from the 1997 China Health National Survey (1385 children, ages 6 to 11 years), conducted with a representative sample from nine provinces. The 2000 Centers for Disease Control and Prevention BMI charts were used to calculate "at risk of overweight" as those above the 85th percentile. Three days of 24-hour recall dietary data and detailed questions on physical activity and inactivity for the previous 7 days were used. Results: 9.4% of the children were classified as overweight. Weekly mean and range of hours spent watching television/ videos, playing video games, studying, and in inactive transport were 5.1 (0 to 35), 0.3 (0 to 10), 4.7 (0 to 60), and 0.14 (0 to 4.2), respectively. Television/video viewing and studying did not differ in any meaningful manner between overweight and normal weight children. Snacking is inconsequential in China, comprising only 0.9% of energy intake. Discussion: Chinese children are less overweight, less inactive, and less likely to ingest calories as snacks than children in the U.S. The absence of impact of these measures of inactivity, which are below an hour per day for the average Chinese child, indicate the possible value of limiting television viewing and other types of inactivity in other countries. Modern Western-style television programming and advertising started to come to China after 1997; therefore, extensive changes in television viewing patterns are expected to emerge. Read more...

Objectives: Obesity prevention among children and adolescents is a public health priority; however, limited school-based intervention trials targeting obesity have been conducted. This article provides an overview of the study design and baseline preliminary findings of our ongoing school-based intervention study. Design: Randomized intervention trial to test a school-based, environmental obesity prevention program in urban low socioeconomic status (SES) African-American adolescents. The intervention program was developed based on several behavioral theories and was guided by preliminary findings based on focus group discussion and baseline data. Setting: Four Chicago public schools in the US. Subjects: Over 450 5 - 7th graders and their families and schools were involved. Results: Our baseline data indicate a high prevalence of overweight (43% in boys and 41% in girls) and a number of problems in these children's physical activity and eating patterns. Only 26% reported spending >= 20 min engaged in vigorous-moderate exercise in >= 5 days over the past 7 days; 29% reported spending >= 5 h each day watching TV, playing video games, or using computer. They also consumed too many fried foods and soft drinks. On average, 55% consumed fried foods >= 2 times/day over the past 7 days; regarding soft drinks, 70% reported consuming >= 2 times/day. Conclusion: School-based obesity prevention programs are urgently needed in the target US urban, low SES, minority communities. These data can be used to inform intervention activities. Read more...