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.

Acute Effect of Intermittent Exercise and Action-Based Video Game Breaks on Math Performance in Preadolescent Children.

PURPOSE: The purpose of this study was to compare the acute effects of video game breaks and intermittent exercise breaks, performed at varying intensities, on math performance in preadolescent children. METHODS: A total of 39 children (18 males and 21 females; aged 7-11 y) completed 4 experimental conditions in random order: 8 hours of sitting interrupted with 20 two-minute low-, moderate-, or high-intensity exercise breaks or 20 two-minute sedentary computer game breaks. The intensity of exercise breaks for the low-, moderate-, and high-intensity conditions corresponded with 25%, 50%, and 75% of heart rate reserve, respectively. Math performance was assessed 3 times throughout each condition day using a 90-second math test consisting of 40 single-digit addition and subtraction questions. RESULTS: There were no significant differences in percent change in math scores (correct answers out of attempted) by condition [low: -1.3 (0.8), moderate: 0.1 (1.3), high: -1.8 (0.7), and computer: -2.5 (0.8); P > .05]. There were significant differences in percent change in math scores over the course of the condition days with lower math scores reported at end-of-day test compared with midday test [-2.4 (0.5) vs -0.4 (0.3); P = .01]. There were no significant condition × time, time × age, condition × age, or condition × time × age interactions (all Ps > .05). CONCLUSION: Action-based video game and exercise breaks elicit the same level of math performance in children; however, time of day may impact this relationship. These findings may have important implications for instructional time in elementary classrooms.

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.

Affective Responses to Intermittent Physical Activity in Healthy Weight and Overweight/Obese Elementary School-Age Children.

BACKGROUND: The purpose of this study was to examine the acute effects of intermittent physical activity (2-min bouts of varying intensities) on psychological mood and enjoyment in elementary school-age children and to examine the effect of weight status on these psychological outcomes. METHODS: A total of 39 children (healthy weight, n = 26; overweight/obese, n = 13) completed 4 experimental conditions in random order, which consisted of 8 hours of sitting interrupted with 20 two-minute low--, moderate-, or high-intensity activity breaks or 20 two-minute screen-time breaks. Mood was assessed using the Feeling Scale immediately following each break. Enjoyment was assessed using the Physical Activity Enjoyment Scale immediately following 10 and 20 breaks. RESULTS: Mood was significantly higher during the sedentary versus active conditions (P < .01). Overweight/obese children reported lower mood scores compared with healthy weight children at the initiation of the low- (P < .05) and high-intensity conditions (P < .001) but experienced improvements in mood throughout the day in all 3 active conditions (P = .02). Enjoyment was significantly higher after completing the active versus sedentary conditions (P = .02). CONCLUSION: These findings suggest that both healthy weight and overweight/obese children felt better immediately after engaging in screen-time breaks but subsequently rated the activity breaks as more enjoyable compared with screen-time breaks.