Active Class Space Metabolic Benefits Study

Background: A range of metabolic, behavioral, mental and physical health benefits of regular
physical activity have been documented in adults and children in the long-term. Yet,
relatively little is known about how children's usual daily physical activity patterns (i.e.
small bursts throughout the day) affect acute (immediately post-activity) and short-term (72
hours post-activity) metabolic and psychosocial outcomes. Additionally, little is known how
this specific pattern of physical activity affects subsequent physical activity levels (i.e.
compensatory behavior) and subsequent dietary intake, over the short-term- information
critical to designing effective interventions involving the physical environment of the
school classroom. Overall Goal: Active Class Space (ACS) will examine the potential
influence of intermittent physical activity breaks of various intensities (control, light,
moderate, vigorous) on measures of immediate mental performance, mood, hunger and several
metabolic outcomes in children aged 7-11 years. We build upon previous work to hypothesize
that higher-intensity intermittent physical activity breaks throughout an 8-hour day will
improve immediate mental performance, mood, and post-exercise physical activity levels,
while reducing hunger and post-exercise food intake. Specific Aims: (1) To determine the
effects of intermittent physical activity breaks of varying intensities on immediate mental
performance, hunger and satiety; (2) To determine the effects of intermittent activity
breaks of varying intensities on ratings of perceived exertion (RPE), perceived exercise
enjoyment, in-task mood, post-exercise food intake and post-exercise physical activity
levels; and (3) To examine gender differences in the preceding variables in response to
low-, moderate, and high-intensity intermittent physical activity. Design: Eighteen healthy
males and twenty-one healthy females between the ages of 7-11 years completed completed four
experimental conditions in random order: (1) 8 hours of sitting interrupted with 2--minute,
light--intensity activity breaks performed at 25% of heart rate reserve (HRR) every 18
minutes; (2) 8 hours of sitting interrupted with 2--minute, moderate--intensity activity
breaks (50% HRR); (3) 8 hours of sitting interrupted with 2--minute, high--intensity
activity breaks (75% HRR); and (4) 8 hours of sitting interrupted with 2 minutes of
sedentary screen time. Standardized meals will be provided during each experimental
condition. Dietary intake and physical activity levels were monitored for the remainder of
the experimental day and over the subsequent three days for each condition. Dependent
Variables: Major outcome variables include: Energy expenditure measured by indirect
calorimetry and heart rate; dietary intake measured using a 3-day dietary record; physical
activity measured by accelerometry; immediate mental performance assessed using a 90-sec
mathematical computation test; hunger and satiety assessed using a visual analog scale; RPE
assessed using the Borg scale; perceived exercise enjoyment assessed using the physical
activity enjoyment scale (PACES); in-task mood assessed using the Feeling Scale (FS) and
Subjective Exercise Experiences Scale (SEES). Data Analysis: A linear mixed model will be
fitted for each outcome variable with effects for condition, sex, BMI, and baseline physical
activity level. A Bonferroni correction will be used to adjust for multiple comparisons in
post hoc tests following the mixed-effect model. A similar linear mixed-model for raw levels
of each outcome variable over time will also be fitted to assess temporal differences
between conditions. This model will include effects for condition, time, time-by-condition
interaction, sex, BMI, and baseline physical activity levels. Significance: ACS will shed
new light on the short-term metabolic, behavioral, mental and physical health benefits of
intermittent physical activity breaks in children. The results from this study will inform
the design of behavioral and environmental interventions to promote physical activity and
cognitive development in pediatric populations.

Inclusion Criteria:

- Children ages 7-11 years old from the greater Ann Arbor and Ypsilanti areas were
recruited to participate in this study.

Exclusion Criteria:

- Participants were excluded based on the following criteria: (1) were taking
medications or were diagnosed with diseases that could influence exercise ability or
cognitive function and (2) were previously diagnosed with any major illness/health
condition since birth.