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  • Author: Molly O’Sullivan x
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Emma Weston, Matthew Nagy, Tiwaloluwa A. Ajibewa, Molly O’Sullivan, Shannon Block and Rebecca E. Hasson

Purpose: To compare the acute effects of intermittent physical activity (PA) across 4 different intensities on blood pressure. Methods: Thirty children (12 males and 18 females; aged 7–11 y; 33% overweight/obese; 53% nonwhite) completed 4 experimental conditions in random order: 8 hours sitting interrupted with 20, 2-minute low-, moderate-, high-intensity PA breaks, or sedentary screen-time breaks. PA intensity corresponded with 25%, 50%, and 75% of heart rate reserve. Blood pressure was measured during each condition in the morning (0800 h), noon (1200 h), and afternoon (1600 h). Results: There were no significant differences across conditions for systolic blood pressure (SBP; all Ps > .05). There was a significant effect of time with SBP decreasing throughout the day for all conditions (average morning SBP: 106 [1] mm Hg, average noon SBP: 101 [2] mm Hg, average afternoon SBP: 103 [1] mm Hg; P = .01). There were no significant effects of condition or time on diastolic blood pressure (all Ps > .05). Conclusion: While sedentary behavior is known to be associated with hypertension in both adults and children, a single bout of prolonged sitting may be insufficient to produce hypertensive effects in otherwise healthy children. Future research should examine the appropriate dose of intermittent PA to accrue hypotensive responses in preadolescent children.

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Matthew R. Nagy, Molly P. O’Sullivan, Shannon S. Block, Trevor R. Tooley, Leah E. Robinson, Natalie Colabianchi and Rebecca E. Hasson

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.

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Molly P. O’Sullivan, Matthew R. Nagy, Shannon S. Block, Trevor R. Tooley, Leah E. Robinson, Natalie Colabianchi and Rebecca E. Hasson

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.

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Shannon S. Block, Trevor R. Tooley, Matthew R. Nagy, Molly P. O’Sullivan, Leah E. Robinson, Natalie Colabianchi and Rebecca E. Hasson

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.