Sedentary Behaviors From K. Janz

16 hr waking

~ 14 hr waking

Waking Time Children (8-10 yr) Time Spent in Various Activity Intensities Using Accelerometry Pearce 2012 PlosOne

We are (probably) all trading light time for sedentary time.

Energy Expenditure (Thermogensis) Total (TEE) includes resting, thermic effect of food, thermic effect of physical activity (AEE). Kcal/d (absolute) Kcal/d average U.S. Adult 2000 to to 8 y.o 1200 to to 18 y.o to 1800

Non-Exercise Activity Thermogenesis AEE fidgeting, maintain posture, other activities of daily life usually light intensity. NEAT = AEE that is not purposeful exercise. College-age male, 75 kg, TEE = 2700 Kcal, 65% REE (1755 Kcal), 10% DEE (270 Kcal), 25% AEE (675 Kcal), Exercises daily 30 min, 6 METs (.5 hr of circuit training) 6 x 75 x.5 = 225 Kcal per day exercise Example converted from Tremblay

Non-Exercise Activity Thermogenesis AEE = 675 Kcal = 25% TEE Exercise = 225 Kcal (1/3 AEE) Most are NEAT Kcal (2/3 or 450 Kcal) Need for opportunities for increasing PA levels. AEE = Kcal/d

Conceptualization and Measurement: Small Decreases Energy Expenditure Self-selected walking speed gym shoes = 4 mi/hr (70 kcal/mi) Self-selected walking speed flip-flops = 3.6 mi/hr (55 kcal/mi) College students 5 mi/d (10,000 steps/d) 15 x 5 = 75 Theoretically 75 kcal/d from one small change in fashion Campus flip-flop season starts early—lasts long time If 3500 kcal = pound, 1 pound gained in 1.6 months

Calculating Energy Expenditure ˙ > kcal/min moderate > 7 kcal/min vigorous (threshold) Slopes and linearity of slopes differ via activity. Cross-over walking vs running. Kcal/min

Summary Sedentary a Unique Behavior with Unique Antecedents and Health Outcomes Non Exercise Activity Thermogensis Important All Less Light Activity Due to Technology No Solid Evidence Yet of Health Outcomes Effect or Effective Strategies Strategies to Reduce Sedentary Probably Focus on Increasing Light