Children and youth do not compensate for an imposed bout of prolonged sitting by reducing subsequent food intake or increasing physical activity levels: a randomised cross-over study

The effects of acute exercise on food intake and appetite in adolescents with and without obesity: A systematic review and meta-analysis

This systematic review and meta-analysis synthesized evidence pertaining to consummatory and appetitive responses to acute exercise in children and adolescents with and without obesity (5-18 years). Articles reporting on supervised, controlled trials of any modality, duration, or intensity with laboratory-measured food intake were found using MEDLINE, EMBASE, and Cochrane up to July 2023. Differences between conditions in laboratory energy and macronutrient intake, appetite sensations, and food reward were quantitatively synthesized using random-effects meta-analyses. Thirty-five studies were eligible for the systematic review of energy intake, consisting of 60 distinct intervention arms with lean (n = 374) and overweight/obesity participants (n = 325; k = 51 eligible for meta-analysis). Study quality as indicated by the Effective Public Healthy Practice Project tool was rated as low and moderate risk of bias for 80% and 20% of studies, respectively. Acute exercise had no significant effect on energy intake during an ad libitum test meal (mean difference [MD] = -4.52 [-30.58, 21.54] kcal, p = .729). Whilst absolute carbohydrate intake was lower after exercise (23 arms; MD = -6.08 [-11.26, -0.91] g, p = .023), the proportion of carbohydrate was not (30 arms; MD = -0.62 [-3.36, 2.12] %, p = .647). A small elevation in hunger (27 arms; MD = 4.56 [0.75, 8.37] mm, p = .021) and prospective food consumption (27 arms; PFC; MD = 5.71 [1.62, 9.80] mm, p = .008) was observed post-exercise, but not immediately prior to the test meal (Interval: Mdn = 30 min, Range = 0-180). Conversely, a modest decrease in explicit wanting for high-fat foods was evident after exercise (10 arms; MD = -2.22 [-3.96, -0.47] mm, p = .019). Exercise intensity (p = .033) and duration (p = .013) moderated food intake only in youth with overweight/obesity, indicating lower intake at high intensity and short duration. Overall, acute exercise does not lead to compensation of energy intake or a meaningful elevation of appetite or food reward and might have a modest benefit in youth with overweight/obesity if sufficiently intense. However, conclusions are limited by substantial methodological heterogeneity and the small number of trials employing high-intensity exercise, especially in youth with overweight/obesity.

Evening regular activity breaks extend subsequent free-living sleep time in healthy adults: a randomised crossover trial

Objective

To determine if performing regular 3-min bouts of resistance exercise spread over 4 hours in an evening will impact subsequent sleep quantity and quality, sedentary time and physical activity compared with prolonged uninterrupted sitting.

Methods

In this randomised crossover trial, participants each completed two 4-hour interventions commencing at approximately 17:00 hours: (1) prolonged sitting and (2) sitting interrupted with 3 min of bodyweight resistance exercise activity breaks every 30 min. On completion, participants returned to a free-living setting. This paper reports secondary outcomes relating to sleep quality and quantity, physical activity and sedentary time which were assessed using wrist-worn ActiGraph GT3+ accelerometers paired with a sleep and wear time diary.

Results

A total of 28 participants (women, n=20), age 25.6±5.6 years, body mass index 29.5±6.7 kg/m2 (mean±SD) provided data for this analysis. Compared with prolonged sitting, regular activity breaks increased mean sleep period time and time spent asleep by 29.3 min (95% CI: 1.3 to 57.2, p=0.040) and 27.7 min (95% CI: 2.3 to 52.4, p=0.033), respectively, on the night of the intervention. There was no significant effect on mean sleep efficiency (mean: 0.2%, 95% CI: -2.0 to 2.4, p=0.857), wake after sleep onset (1.0 min, 95% CI: -9.6 to 11.7, p=0.849) and number of awakenings (0.8, 95% CI: -1.8 to 3.3, p=0.550). Subsequent 24-hour and 48-hour physical activity patterns were not significantly different.

Conclusions

Performing bodyweight resistance exercise activity breaks in the evening has the potential to improve sleep period and total sleep time and does not disrupt other aspects of sleep quality or subsequent 24-hour physical activity. Future research should explore the longer-term impact of evening activity breaks on sleep.

Trial registration number

Australian New Zealand Clinical Trials Registry (ACTRN12621000250831).

Impact of physical activity on caloric and macronutrient intake in children and adolescents: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Physical activity is widely promoted to maintain and improve health across all ages. Investigating how physical activity affects subsequent food intake provides insight into the factors that contribute to maintaining energy balance and effective weight management.

OBJECTIVE

This systematic review and meta-analysis summarizes the evidence on the effect of acute physical activity on subsequent food intake in children and adolescents.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (PRISMA) were applied. Randomized controlled trials (RCTs) objectively measuring post-exercise energy intake in children and adolescents aged 5 to 18 years were included. Studies with self-reported food intake were excluded. The databases PubMed, Web of Science and Cochrane Library were searched for RCTs, and the data were summarized at a qualitative and quantitative level. Version 2 of the Cochrane risk-of-bias tool for randomized trials was used to assess risk of bias. Changes in energy intake were examined with random effects meta-analysis. (PROSPERO: CRD42022324259).

RESULTS

Out of 9582 studies, 22 RCTs with cross-over design remained eligible for meta-analysis. The primary outcome was post-intervention energy intake up to the next 24 h. Heterogeneity of studies was moderate, with an I2 of 57%. The median (interquartile range, IQR) energy expended while exercising was 240 (158) kcal. Meta-analysis of 41 study arms (exercise n = 780 and control n = 478) showed no differences in total energy intake between the exercise and control group with a mean difference MD = 23.31 [-27.54, 74.15] kcal. No subgroup differences were found. Macronutrient intake and appetite sensations where not substantially affected.

CONCLUSION

Engaging in exercise is a suitable means of raising activity-induced energy expenditure, without causing any noticeable changes in food intake or hunger within a single day.

Exploring Children's Self-Reported Activity Compensation: The REACT Study

PURPOSE

Previous research has focused on device-based measures of activity compensation, with little understanding of how children perceive potential compensatory responses to activity or inactivity, or whether these change after periods of activity or inactivity. The aim of this study was (a) to explore the alignment between children's self-reported usual compensation and compensation recall after experimental conditions and (b) to examine sex differences.

METHODS

In total, 360 children (47% boys) participated in at least one of three experimental conditions over 6 wk: (a) restricted physical activity (PA; indoor play), (b) imposed moderate- to vigorous-intensity PA (MVPA; sports class), and (c) imposed light-intensity PA (LPA; standing lesson). Before the first condition, children reported their "usual compensation" behavior to examples of restricted/imposed PA, and 2-3 d after each experimental condition, they completed a recall measure of their compensation after the condition. Multilevel regression models were conducted to determine whether children's perceptions of "usual compensation" score were associated with recalled compensation score after imposed or restricted PA. Additional models were fitted for sex-specific associations.

RESULTS

Overall and among girls, the usual compensation score was positively associated with the compensatory recall score for the additional MVPA and LPA conditions ( P < 0.0005; e.g., they thought they would usually compensate for additional MVPA and then perceived that they compensated after additional MVPA). A negative association was seen in the restricted activity condition among girls ( P = 0.03). All associations in the boys' analyses were statistically nonsignificant.

CONCLUSIONS

These findings suggest some alignment between children's self-reported usual compensation and compensation recall after imposed changes to routine activity. Future research should consider device-measured comparisons and identify characteristics of children at risk of activity compensation in future interventions.

Exploring activity compensation amongst youth and adults: a systematic review

BACKGROUND

Globally, significant efforts have focused on increasing physical activity and reducing sedentary behaviour in youth and adults across a range of settings (e.g., schools, workplaces, community, and home). Despite this, interventions have had varied efficacy and typically have failed to sustain changes in behaviours over time. One explanation that has been put forth to explain the mixed success of interventions is activity compensation. However, little is known about activity compensation, including whether compensation occurs, and perceptions and potential mechanisms of activity compensation. Understanding activity compensation would assist in tailoring and targeting of potential intervention strategies. The primary aim of this review was to synthesise research that has investigated activity compensation in youth and adults. The secondary aim was to identify potential reasons for and/or awareness of compensatory changes that may have occurred.

METHODS

An electronic search of the EBSCOhost (via Academic Search Complete, CINAHL Complete, Education Source, Health Source: Nursing/Academic Edition, PsycINFO, SPORTdiscus with Full Text), MEDLINE Complete, Global Health, EMBASE, Scopus and Web of Science databases up to May 2021 was conducted. Quality assessment of included quantitative studies used a modified compensation-specific McMaster Quality Assessment Tool.

RESULTS

A total of 44 studies met the inclusion criteria (22 = adult populations; 22 = youth populations) and were classified as (1) quantitative (n = 31); (2) combination of quantitative and behavioural (n = 11); (3) behavioural only (n = 1); and (4) qualitative (n = 1). Of the 42 studies that included a quantitative component, 11 (26%) reported compensation occurred. Within the 13 studies examining specific behaviours, 35 behaviours were assessed, and evidence of compensation was inconsistent. Compensation mechanisms included fatigue, time constraints, lack of motivation, drive to be inactive, fear of overexertion, and autonomous motivation.

CONCLUSION

Little evidence of compensation was reported in the included quantitative studies; however, inconsistencies between studies makes comparisons difficult. There was considerable variability in the types of behaviours assessed in quantitative studies, and few studies examined potential compensatory mechanisms. Future research, using compensation specific study designs, methods, and analytic techniques, within different population sub-groups, should address these evidence gaps.

Acute after-school screen time in children decreases impulse control and activation toward high-calorie food stimuli in brain regions related to reward and attention

The purpose of this study was to examine the effects of after-school sedentary screen time on children's brain activation in reward and cognitive control regions in response to pictures of high- and low-calorie foods. Thirty-two children participated in a randomized crossover study with counterbalanced treatment conditions. Conditions took place on separate days after school and included three hours of active or sedentary play. After each condition, neural activation was assessed using functional magnetic resonance imaging (fMRI) while participants completed a go/no-go task involving pictures of high- and low-calorie foods. General response inhibition was also measured using the Stroop task. Hunger was measured upon arrival to the testing facility and just prior to fMRI scans. Mixed effects models were used to evaluate main effects and interactions. Significant stimulus by condition interactions were found in the right superior parietal cortex, and left anterior cingulate cortex (Ps ≤ 0.05). High-calorie pictures elicited significantly more activation bilaterally in the orbitofrontal cortex compared to low-calorie pictures (Ps ≤ 0.05). Stroop task performance diminished significantly following the sedentary condition compared to the active (P ≤ 0.05). Subjective feelings of hunger were not different between conditions at any point. Sedentary screen time was associated with significantly decreased response inhibition and a reversed brain activation pattern to pictures of high- and low-calorie foods compared to active play, in areas of the brain important to the modulation of food intake. Decreased attention, and impulse control following sedentary screen time may contribute to disinhibited eating that can lead to overweight and obesity.

The Acute Effects of a "Reduced Sitting Preschool Day" on Executive Function and Musculoskeletal Health in Preschoolers: A Randomized Cross-Over Study

PURPOSE

To examine the acute effects of a reduced sitting day on executive function (EF) and musculoskeletal health in preschoolers.

METHODS

A sample of 29 children (54% boys; 4-5 y) participated in a randomized cross-over trial. Each child completed 2 protocols, which simulate a day at childcare in random order for 2.5 hours; a typical preschool day (50% sitting) and a reduced preschool day (25% sitting) where most sitting activities were replaced with standing activities. Sitting, standing, and stepping time were objectively assessed using an activPAL accelerometer. EF was evaluated using tablet-based EF assessments (inhibition, working memory, and task shifting). Musculoskeletal health was assessed using a handheld dynamometer and goniometer.

RESULTS

Compared with the typical preschool day, the reduced sitting day showed no significant differences for EF scores. Effect sizes for inhibition (d = 0.04), working memory (d = 0.02), and shifting (d = 0.11) were all small. For musculoskeletal health, no significant differences were reported after the reduced preschool day. The effect sizes for the hip extension force, hamstring flexibility, gastrocnemius length, and balancing on 1 leg were all small (d = 0.21, d = 0.25, d = 0.28, and d = 0.28).

CONCLUSIONS

This study suggests that reducing sitting time is unlikely to result in acute changes in EF and musculoskeletal health among preschoolers.

Acute Compensatory Responses to Interrupting Prolonged Sitting With Intermittent Activity in Preadolescent Children

PURPOSE

The purpose of this study was to compare the effects of intermittent activity performed at varying intensities and of prolonged sitting on physical activity compensation.

METHODS

A total of 33 children (14 boys and 19 girls; age 7-11 y; 24% overweight/obese; 61% nonwhite) completed 4 experimental conditions in random order: 8 hours of sitting interrupted with 20 two-minute low-, moderate-, or high-intensity activity breaks or 20 two-minute sedentary computer game breaks. Physical activity energy expenditure (PAEE) was assessed via accelerometry to establish baseline PAEE and throughout each condition day (8-h in-lab PAEE, out-of-lab PAEE, and 3-d postcondition).

RESULTS

Compared with baseline PAEE, total daily PAEE was significantly higher during the high-intensity condition day (153 ± 43 kcal, P = .03), unchanged during the low-intensity (-40 ± 23 kcal, P > .05) and moderate-intensity condition days (-11 ± 18 kcal, P > .05), and decreased in response to prolonged sitting (-79 ± 22 kcal, P = .03). There were no significant differences in PAEE 3-day postcondition across conditions (P > .05).

CONCLUSION

Despite the varying levels of PAEE accumulated during the 8-hour laboratory conditions, out-of-lab PAEE during each condition day and 3-day postcondition did not change from the baseline. These findings provide preliminary evidence that spontaneous physical activity in children does not change in response to intermittent activity or prolonged sitting.

The effects of interrupting prolonged sitting with intermittent activity on appetite sensations and subsequent food intake in preadolescent children

Background

Short-term and long-term exposure to prolonged sitting is associated with excess food intake and weight gain in children. Interrupting prolonged sitting with low-intensity activity has been shown to not alter hunger, satiety, or food consumption in children, however it is unclear whether interrupting sitting with high-intensity activity will alter appetite regulation in children.

Purpose

The purpose of this study was to examine the acute effects of interrupting prolonged sitting with intermittent activity performed at varying intensities on hunger, satiety, prospective food consumption (PFC), and food intake in preadolescent children.

Methods

Thirty-nine children (ages 7–11 years, 54% female, 33% overweight/obese) completed four experimental conditions in random order: 8 hours of sitting interrupted with 20, 2-minute low-, moderate-, or high-intensity activity breaks or 20, 2-minute sedentary screen time breaks. Exercise intensity corresponded with 25%, 50% and 75% of heart rate reserve, respectively. Hunger, satiety, and PFC were assessed using the Visual Analog Scale, at five time points (pre- and post-breakfast, pre- and post-lunch, and pre-dinner) during each experimental condition. Dietary compensation was assessed as total caloric intake during a post-condition dinner standardized to provide 70% of estimated daily energy requirements.

Results

There was a significant effect of time on hunger, satiety, and PFC throughout each condition day (p< 0.001). There were no differences across conditions for hunger (sedentary: 4.9±0.3 cm, low: 5.0±0.3 cm, moderate: 5.1±0.3 cm, high: 5.1±0.3 cm, p>0.05), satiety (sedentary: 4.7±0.3 cm, low: 4.4±0.3 cm, moderate: 4.6±0.3 cm, high: 4.2±0.3 cm, p>0.05), and PFC (sedentary: 4.9±0.3 cm, low: 4.7±0.3 cm, moderate: 4.9±0.3 cm, high: 5.0±0.3 cm, p>0.05). There were no significant differences in post-activity food intake across conditions (sedentary: 1071.9±53.6 kcals; low: 1092.6±43.4kcals; moderate: 996.2±54.6kcals; high: 1138.7±62.8kcals, p>0.05). However, there was a significant effect of condition on energy balance (sedentary: +61.4±65.9 kcals, low: +74.9±57.6 kcals, moderate: -58.3±62.8 kcals, high: -391.2±77.9 kcals; p<0.001). There were no significant effects of weight status on hunger, satiety, PFC, post-activity food intake, and mean energy balance across conditions (all p’s>0.05).

Conclusions

Interrupting prolonged sitting with physical activity of any intensity does not alter appetite sensations and subsequent food consumption in children. These data suggest that interventions targeting prolonged sitting with high-intensity intermittent activity may be an effective strategy to increase physical activity energy expenditure without increasing food intake, allowing for a short-term energy deficit in both healthy weight and overweight/obese children. Future studies should examine the long-term effects of interrupting prolonged sitting with activity on food consumption and weight status in preadolescent children.

Acute effects of reducing sitting time in adolescents: a randomized cross-over study

BACKGROUND

Levels of sitting among adolescents are high, especially during the school day. The acute cognitive and health consequences associated with prolonged sitting are poorly understood in adolescents. This randomized crossover design study examined the acute effects of a simulated school day with reduced sitting or usual sitting on adolescents' cognitive function and cardiometabolic biomarkers.

METHODS

Eighteen healthy school aged adolescents were recruited from the community to the study (11 males; 7 females; mean age [SD] = 13.5 ± 0.9 years). Two protocols were developed to simulate an adolescent school day, the amount of time spent sitting was manipulated reflecting: a 'typical' day (65% of the time spent sitting with two sitting bouts sitting >20 min) and a 'reduced sitting' day (adolescents sat for 50% less time with no bouts of sitting >20 mins). The order that participants were exposed to each condition was randomized (via random number generator). Participants were not fully blinded as they could observe the difference between conditions. Energy intake and moderate to vigorous physical activity (MVPA) were standardized for both conditions and monitored for 48 h post-condition for compensatory effects. Cognitive (working memory) and cardiometabolic outcomes (lipids, glucose, insulin, IL-6, apo-A1, apo-B, blood pressure,) were assessed pre and post for both conditions, BMI and body fat were assessed on the morning of the intervention. Data were analyzed using linear mixed models. Standardised effect sizes were calculated.

RESULTS

Compared with the typical school day, the reduced sitting day demonstrated significant positive effects for apoB/apoA-1 ratio (adjusted difference ± SD) -0.02 ± 0.03; P = 0.03; effect size [Cohen's d] = -0.67. Findings for total cholesterol -0.19 ± 0.27; P = 0.28; d = -0.71; HDL cholesterol -0.23 ± 0.50; P = 0.12 d = -0.66; and total cholesterol/HDL ratio 0.25 ± 0.53; P = 0.25; d = 0.51 and for cognition 0.64 ± 0.15; P = 0.15; d = 0.54 were non-significant. There were no compensatory changes in participant energy expenditure or energy intake for 48 h post intervention.

CONCLUSION

Reducing school day sitting time in adolescents' resulted in significant improvements in apoB/apoA-1 ratio with medium effect sizes for total cholesterol, HDL cholesterol and total cholesterol/HDL ratio. Cognitive function results showed the equivalent of a 6 month improvement in effective mental-attentional capacity.

TRIAL REGISTRATION

The trial was registered as a clinical trial with the Australian and New Zealand Clinical Trials Registry ( ACTRN12614001064695 ) on the 3rd of October 2014 - registered retrospectively.

Screen Time and Health Indicators Among Children and Youth: Current Evidence, Limitations and Future Directions

Despite accumulating evidence linking screen-based sedentary behaviours (i.e. screen time) with poorer health outcomes among children and youth <18 years of age, the prevalence of these behaviours continues to increase, with roughly half of children and youth exceeding the public health screen time recommendation of 2 h per day or less. The purpose of this article is to provide an overview of key research initiatives aimed at understanding the associations between screen time and health indicators including physical health, quality of life and psychosocial health. Available evidence suggests that screen time is deleteriously associated with numerous health indicators in child and youth populations, including adiposity, aerobic fitness, quality of life, self-esteem, pro-social behaviour, academic achievement, depression and anxiety. However, few longitudinal or intervention studies have been conducted, with most of these studies focusing on physical health indicators. While most studies have used self-reported assessments of screen time, the availability of more objective assessment methods presents important opportunities (e.g. more accurate and precise assessment of sedentary time and screen time) and challenges (e.g. privacy and participant burden). Novel statistical approaches such as isotemporal substitution modelling and compositional analysis, as well as studies using longitudinal and experimental methodologies, are needed to better understand the health impact of excessive screen time, and to develop strategies to minimise or reverse the negative impacts of these behaviours. The evidence to date suggests a clear need for policy aimed at minimising the hazardous health consequences associated with screen time among children and youth.

Objectively measured sedentary behaviour and moderate and vigorous physical activity in different school subjects: a cross-sectional study

BACKGROUND

Evidence shows the positive influence of moderate and vigorous physical activity (MVPA) and negative influence of sedentary time on health and academic achievement. Although schools can significantly contribute to overall physical activity, little is known about MVPA and sedentary behaviour in different school subjects in different grades.

METHODS

Physical activity of 646 students from 18 schools (94 classes) and from three school stages (grades 1-9, aged 7-16) was measured with accelerometry for 5 school days. Time and proportion of MVPA and sedentary time, also average sedentary bout length was calculated for native language (Estonian), mathematics, science, foreign language, music and crafts lessons.

RESULTS

A total of 6363 lessons were measured, with lesson duration of 45 min. The average lesson time MVPA remained below 2.2 min in all school stages and in all subjects. Students in grades 4-6 had greatest decline in the proportion of lesson time MVPA in science (β = -1.9, 95%CI -3.1- -0.6) and music (-1.2, -2.1- -0.4) and in grades 7-9 in music (-1.7, -3.1- -0.3) lessons compared to grades 1-3. In grades 1-3 students spent on average 76% of lesson time (34.0 ± 7.0 min) as sedentary, whereas in grades 7-9 the average proportion of sedentary time was 87% (38.9 ± 5.7 min). An average sedentary bout length increased from 13 min in grades 1-3 to 20 min in grades 7-9. An increase in sedentary bout length from grades 1-3 compared to grades 7-9 was present in most subjects, except crafts, with smallest increase in foreign language (6 min, 3.5-8.9) and greatest in music lessons (16.6 min, 11.9-21.3). Lessons with prolonged sedentary bouts formed a maximum 36% of all lessons in grades 1-3 and 73% in grades 7-9.

CONCLUSION

The long sedentary time, bout length and low MVPA in most subjects were unfavourable in respect of both health and academic achievement. Significantly increasing sedentary time and sedentary bout length in older school stages highlights the need for interventions in all subjects and especially in older grades in order to combat the inactivity of children.

Testing the activitystat hypothesis: a randomised controlled trial

BACKGROUND

It has been hypothesised that an 'activitystat' may biologically regulate energy expenditure or physical activity levels, thereby limiting the effectiveness of physical activity interventions. Using a randomised controlled trial design, the aim of this study was to investigate the effect of a six-week exercise stimulus on energy expenditure and physical activity, in order to empirically test this hypothesis.

METHODS

Previously inactive adults (n = 129) [age (mean ± SD) 41 ± 11 year; body mass index 26.1 ± 5.2 kg/m(2)] were randomly allocated to a Control group (n = 43) or a 6-week Moderate (150 min/week) (n = 43) or Extensive (300 min/week) (n = 43) exercise intervention group. Energy expenditure and physical activity were measured using a combination of accelerometry (total counts, minutes spent in moderate to vigorous physical activity) and detailed time use recalls using the Multimedia Activity Recall for Children and Adults (total daily energy expenditure, minutes spent in moderate to vigorous physical activity) at baseline, mid- and end-intervention and 3- and 6-month follow up. Resting metabolic rate was measured at baseline and end-intervention using indirect calorimetry. Analysis was conducted using random effects mixed modeling.

RESULTS

At end-intervention, there were statistically significant increases in all energy expenditure and physical activity variables according to both accelerometry and time use recalls (p < 0.001) in the Moderate and Extensive groups, relative to Controls. There was no significant change in resting metabolic rate (p = 0.78).

CONCLUSION

Taken together, these results show no evidence of an "activitystat" effect. In the current study, imposed exercise stimuli of 150-300 min/week resulted in commensurate increases in overall energy expenditure and physical activity, with no sign of compensation in either of these constructs.

TRIAL REGISTRATION NUMBER

ACTRN12610000248066  (registered prospectively 24 March 2010).

In-school versus out-of-school sedentary behavior patterns in U.S. children

Background

This study contributes to the literature by using accelerometers to describe sedentary behavior (SB) patterns in US children. The purpose of this study was to examine SB patterns in fifth-graders by specifically focusing on in-school versus out-of-school SB patterns to identify when (during the school day or outside of the school day) interventions should take place in order to decrease SB in children.

Methods

Data were collected from 206 fifth-graders (9–11 years old) in the Cherry Creek School District in metro Denver, Colorado (USA) during the spring of the 2010–2011 school year and fall of the 2011–2012 school year. Children wore Actical accelerometers continuously over an eight-day period. Data were analyzed using Wilcoxon rank tests, paired samples t-tests, and independent samples t-tests. Awake time was 6 AM–11 PM. We compared the percent of time spent in SB before school, during school, at recess/lunch and after school, as well as differences between boys and girls, and between children from low and high socioeconomic status schools. Children were classified as ‘non-sedentary’ or ‘sedentary’ if they participated in <360 min or ≥360 min per day of SB, respectively and were classified as ‘inactive’ or ‘active’ if they participated in <60 min or ≥ 60 min per day of MVPA, respectively.

Cross-tabs were used (and Fisher’s exact test) to identify the proportion of children in the following categories: 1) non-sedentary/inactive; 2) sedentary/inactive; 3) non-sedentary/active; and 4) sedentary/active. Statistical significance was set at p < 0.05.

Results

All children (boys and girls and children from low and high socioeconomic status schools) participated in significantly more SB outside of school hours versus during school hours and on weekend days compared to weekdays (p < 0.001). Girls participated in significantly more SB than boys during weekdays (p = 0.015). The majority of children (65.3 %) were classified as sedentary/active.

Conclusions

Given that children appear to be more sedentary during the weekend, where more opportunities to be physically active with the whole family can easily be implemented, future interventions should focus on time periods outside of school hours in order to decrease sedentary behavior and increase light physical activity in particular.

Active Video Games in Schools and Effects on Physical Activity and Health: A Systematic Review

OBJECTIVE

To assess the quality of evidence for the effects of school active video game (AVG) use on physical activity and health outcomes.

STUDY DESIGN

Online databases (ERIC, PsycINFO, PubMed, SPORTDiscus, and Web of Science) and gray literature were searched. Inclusion criteria were the use of AVGs in school settings as an intervention; assessment of at least 1 health or physical activity outcome; and comparison of outcomes with either a control group or comparison phase. Studies featuring AVGs within complex interventions were excluded. Study quality was assessed using the Effective Public Health Practice Project tool.

RESULTS

Twenty-two reports were identified: 11 assessed physical activity outcomes only, 5 assessed motor skill outcomes only, and 6 assessed both physical activity and health outcomes. Nine out of 14 studies found greater physical activity in AVG sessions compared with controls; mostly assessed by objective measures in school time only. Motor skills were found to improve with AVGs vs controls in all studies but not compared with other motor skill interventions. Effects of AVGs on body composition were mixed. Study quality was low in 16 studies and moderate in the remaining 6, with insufficient detail given on blinding, participation rates, and confounding variables.

CONCLUSIONS

There is currently insufficient evidence to recommend AVGs as efficacious health interventions within schools. Higher quality AVG research utilizing randomized controlled trial designs, larger sample sizes, and validated activity measurements beyond the school day is needed.

Food intake response to exercise and active video gaming in adolescents: effect of weight status

Although a few data are available regarding the impact of video games on energy intake (EI) in lean adolescents, there is no evidence on the effect of passive and active video gaming on food intake in both lean and obese youth. It is also unknown whether isoenergetic active video games and exercise differently affect food consumption in youth. In all, twelve lean and twelve obese adolescent boys (12-15 years old) had to complete four 1-h sessions in a cross-over design study: control (CON; sitting), passive video game (PVG; boxing game on Xbox 360), active video game (AVG; boxing game on Xbox Kinect 360) and exercise (EX; cycling). The exercise and active video game activities were designed to generate the same energy expenditure (EE). EE was measured using a K4b2 portable indirect calorimeter. Ad libitum food intake and appetite sensations were assessed following the sessions. AVG and EX-EE were significantly higher in obese participants and significantly higher compared with PVG and CON in both groups. Obese participants significantly ate more than lean ones in all four conditions (P<0·001). EI did not differ between conditions in obese participants (CON: 4935 (SD 1490) kJ; PVG: 4902 (SD 1307) kJ; AVG: 4728 (SD 1358) kJ; EX: 4643 (SD 1335) kJ), and was significantly lower in lean participants after EX (2847 (SD 577) kJ) compared with PVG (3580 (SD 863) kJ) and AVG (3485 (SD 643) kJ) (P<0·05). Macronutrient intake was not significantly different between the groups or conditions. Hunger was significantly higher and satiety was lower in obese participants but no condition effect was observed. Overall, moderate-intensity exercise provides better effect on energy balance than an isoenergetic hour of active video gaming in lean adolescent boys by dually affecting EE and EI.

Effects of Interrupting Children's Sedentary Behaviors With Activity on Metabolic Function: A Randomized Trial

CONTEXT

Limited data suggest that interrupting sedentary behaviors with activity improves metabolic parameters in adults.

OBJECTIVE

We tested whether interrupting sitting with short, moderate-intensity walking bouts improved glucose tolerance in children.

DESIGN

Participants underwent two experimental conditions in random order on different days: continuous sitting for 3 hours or sitting interrupted by walking (3 min of moderate-intensity walking every 30 min). Insulin, C-peptide, glucose, and free fatty acids were measured every 30 minutes for 3 hours during an oral glucose tolerance test. Area under the curve (AUC) was calculated from hormone and substrate measurements. Children were given a buffet meal after each condition.

SETTING

The study was conducted at the National Institutes of Health Hatfield Clinical Research Center.

PARTICIPANTS

Twenty-eight normal-weight 7-11 year olds participated.

MAIN OUTCOMES

Patterns of substrate/hormone secretion and AUC, as well as energy intake, were examined by experimental condition.

RESULTS

Interrupting sitting resulted in a 32% lower insulin AUC (P < .001), 17% lower C-peptide AUC (P < .001), and 7% lower glucose AUC (P = .018) vs continuous sitting. Mixed model results indicated that insulin (P = .036) and free fatty acid concentrations (P = .009) were significantly lower in the interrupted vs the continuous sitting condition. Lunchtime buffet meal energy intake did not significantly differ between the conditions (975 ± 387 vs 963 ± 309 kcal; P = .85).

CONCLUSIONS

Interrupting sedentary time with brief moderate-intensity walking improved short-term metabolic function in non-overweight children without increasing subsequent energy intake. These findings suggest that interrupting sedentary behavior may be a promising prevention strategy for reducing cardiometabolic risk in children.

Within- and between-day associations between children's sitting and physical activity time

Background

The objective of this study was to examine whether increased levels of sitting time and physical activity in one period (within-day) or on one day (between-day) were predictive of lower levels in these behaviours in the following period or day among children.

Methods

Children aged 8–11 years from 8 primary schools located in Melbourne, Australia, wore an activPAL for 7 consecutive days (n = 235; 53 % boys). Sitting, standing and stepping time were derived for each day and for specific periods on weekdays and weekend days. Multilevel analyses were conducted using generalised linear latent and mixed models to estimate associations between temporally adjacent values (i.e. pairs of days; pairs of periods within-days) between the outcome variables.

Results

Significant associations were observed between temporally adjacent days and periods of the day. On any given day, an additional 10 min of stepping was associated with fewer minutes of stepping (~9 min; 95 % CI: −11.5 to −6.2 min) and standing (15 min; 95 % CI: −18.8 to −11.1 min) the following day. Greater time spent sitting during one period, regardless of being a weekday or weekend day, was associated with less time sitting and more time standing and stepping in the following period.

Conclusions

The direction of the results suggest that children appeared to compensate for increased sitting, standing, and stepping time both within- and between-days. The implications of such associations for the design and delivery of interventions require consideration.

Virtual field trips as physically active lessons for children: a pilot study

Background

The modern classroom is an inherently sedentary environment. Virtual Field Trips (VFTs) using interactive whiteboards to explore virtual scenes are a potential method of converting sedentary class-time into physically active teaching. This pilot aimed to assess the effects of a developed VFT on physical activity and learning in primary-school children.

Methods

Participants (n = 85) were randomly assigned to a) a 30-minute physically active London 2012 Olympics-themed VFT, or b) a 30-minute sedentary version of the same VFT. Activity was measured using GT1M Actigraphs, content recall was assessed with a quiz and user evaluations were gained from teacher and pupil questionnaires.

Results

Pupils in the active VFT displayed significantly less sedentary time (p < 0.001), and significantly more light (p < 0.001), moderate (p = 0.01) and vigorous physical activity (p < 0.001) than sedentary VFT pupils. No differences in content recall were found between intervention groups: suggesting that adding physical activity into classroom teaching may not compromise attainment. High acceptability was found in teachers and active VFT students rated their session significantly higher than sedentary pupils (p < 0.002).

Conclusions

This one-day pilot provides early evidence of the ability of VFTs to convert sedentary academic time into active time. Longitudinal research is needed to assess prolonged effects of active VFTs in reducing sedentary time.

Sedentary behaviour as an emerging risk factor for cardiometabolic diseases in children and youth

Sedentary behaviour (e.g. TV viewing, seated video game playing, prolonged sitting) has recently emerged as a distinct risk factor for cardiometabolic diseases in children and youth. This narrative review provides an overview of recent evidence in this area and highlights research gaps. Current evidence suggests that North American children and youth spend between 40% and 60% of their waking hours engaging in sedentary pursuits. Although data are lacking concerning temporal trends of objectively measured sedentary time, self-reported sedentary behaviours have increased over the past half century, with a rapid increase since the late 1990s. Excessive sedentary behaviour has been found to have independent and deleterious associations with markers of adiposity and cardiometabolic disease risk. These associations are especially consistent for screen-based sedentary behaviours (TV viewing, computer games, etc), with more conflicting findings observed for overall sedentary time. The above associations are possibly mediated by the influence of screen-based sedentary behaviours on energy intake. Although excessive sitting has been reported to have adverse acute and chronic metabolic impacts in adults, research on children is lacking. Research is particularly needed to investigate the impact of characteristics of sedentary behaviour (i.e. type/context, sedentary bout length, breaks in sedentary time, etc), as well as interventions that examine the health and behavioural impacts of sitting per se.

Associations of sedentary behavior, sedentary bouts and breaks in sedentary time with cardiometabolic risk in children with a family history of obesity

BACKGROUND

Although reports in adults suggest that breaks in sedentary time are associated with reduced cardiometabolic risk, these findings have yet to be replicated in children.

PURPOSE

To investigate whether objectively measured sedentary behavior, sedentary bouts or breaks in sedentary time are independently associated with cardiometabolic risk in a cohort of Canadian children aged 8-11 years with a family history of obesity.

METHODS

Data from 286 boys and 236 girls living in Quebec, Canada, with at least one biological parent with obesity (QUALITY cohort) were collected from 2005-2008, and analyzed in 2013. Sedentary behavior, light and moderate-to-vigorous physical activity were measured over 7 days using accelerometry. Leisure time computer/video game use and TV viewing over the past 7 days were self-reported. Outcomes included waist circumference, body mass index Z-score, fasting insulin, fasting glucose, triglycerides, HDL-cholesterol, C-reactive protein and a continuous cardiometabolic risk score.

RESULTS

After adjustment for confounders, breaks in sedentary time and the number of sedentary bouts lasting 1-4 minutes were associated with reduced cardiometabolic risk score and lower BMI Z-score in both sexes (all p<0.05). The number of sedentary bouts lasting 5-9 minutes was negatively associated with waist circumference in girls only, while the number of bouts lasting 10-14 minutes was positively associated with fasting glucose in girls, and with BMI Z-score in boys (all p<0.05). Leisure time computer/video game use was associated with increased cardiometabolic risk score and waist circumference in boys, while TV viewing was associated with increased cardiometabolic risk, waist circumference, and BMI Z-score in girls (all p<0.05).

CONCLUSIONS

These results suggest that frequent interruptions in sedentary time are associated with a favourable cardiometabolic risk profile and highlight the deleterious relationship between screen time and cardiometabolic risk among children with a family history of obesity.