1 FIT Kids: Time in target heart zone and cognitive performance 2 Darla M. Castelli a, ⁎, Charles H. Hillman b , Jennifer Hirsch b , Alayna Hirsch b , Eric Drollette b 3 a Q1 Department of Kinesiology and Health Education, The University of Texas at Austin, USA 4 b Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, USA 5 6 abstract article info 7 8 Available online xxxx 9 10 11 12 Keywords: 13 Physical activity 14 Physical fitness 15 Target heart rate 16 Stroop 17 Trails 18 Executive function 19 This present study examined time spent in the target heart zone (THZ) and its relationship to tasks requiring 20 variable amounts of executive control function in prepubescent children participating in a 9-month ran- 21 domized controlled physical activity program. A sample of 59 participants performed the Stroop Color-Word 22 Test and the Comprehensive Trail Making Test cognitive assessments. Heart rate data were collected during 23 participation in the physical activity program using E600 heart rate monitors (Polar, Finland). Analysis of 24 these data revealed that time above the THZ, representing vigorous physical activity, was a predictor of 25 performance in some of the cognitive tasks and task conditions. These results suggest that heart rate, as a 26 measure of physical activity intensity, should be closely monitored during research that is intended to make 27 inferences about its effects on cognitive performance as participation in vigorous activities may have specific 28 benefits over lower intensities among prepubescent children. 29 © 2011 Published by Elsevier Inc. Q2 30 31 32 33 34 Physical activity has many known benefits for children such as 35 improved physical fitness and reduced risk of disease (Strong et al., 36 2005), yet at least one-third of children do not meet the national 37 guidelines of 60 min of moderate to vigorous activity each day 38 (Centers for Disease Control and Prevention [CDC], 2008). Schools are 39 an ideal place to provide interventions since 98% of children spend 40 approximately six hours each day in attendance (U.S. Census Bureau, 41 2006). Further, physical activity (Hillman et al., 2009a,b; Q4 Donnelly 42 et al., 2009) and physical fitness (Hillman et al., 2005) are associated 43 with success in schools through better attendance (Welk et al., 2010), 44 attention (Mahar, 2006), and academic achievement (Castelli et al., 45 2007). Study of the relationship between physical activity and cogni- 46 tive performance has been around for decades with early research 47 focusing on adult physical fitness and reaction time. The first in-school 48 physical activity study, examined the effects of exertion during physi- 49 cal education class on mathematical computations in second grade 50 students (Gabbard and Barton, 1979). Initial studies such as these 51 were either atheoretical or grounded in the speed hypothesis, which 52 posits that physically active humans would respond faster to simple 53 cognitive tasks than healthy, but inactive humans. Although these 54 studies are considered seminal research, the generalizability is limited 55 because the speed hypothesis did not necessarily account for the 56 complexity of tasks required for achievement in school. 57 Executive control has been evidenced in children as young as 58 12 months old, with age 3.5 generally being the time when behavioral 59 response becomes observable, yet executive function continues to 60 develop until the early twenties (Wiebe et al., 2010). Recently, the 61 executive function hypothesis has been applied to children when 62 comparing processing speed and accuracy to adults (Hillman et al., 63 2005), investigating inhibitory control tasks (Buck et al., 2008), and 64 examining brain function ( Q5 Pontifex et al., in press) and structure 65 (Chaddock et al., 2010a,b). Further, the relationship between physical 66 activity and executive function has been examined from both the 67 acute ( Q6 Hillman et al., 2009a,b) and chronic perspectives (Davis et al., 68 2007) suggesting that a dose–response relationship may exit. Higher 69 doses (40 min of physical activity for 15 weeks) resulted in signifi- 70 cantly better performance in planning tasks over low doses (no phy- 71 sical activity). While Q7 Hillman et al. (2009a,b) found a single bout of 72 light to moderate, treadmill walking can transiently improve execu- 73 tive function beyond that associated with sedentary behaviors. Evi- 74 dence of a dose–response relationship between physical activity and 75 executive function suggests that the intensity of engagement should 76 be closely monitored during the intervention. Given its linear rela- 77 tionship with oxygen uptake (VO 2 ), heart rate telemetry can be used 78 to accurately track physical activity engagement in children (Bassett, 79 2000; Q8 Freedson et al., 2000; Laukkanen and Virtanen, 1998). 80 Technological advances allow heart rate monitors to measure exercise 81 intensity, time in the target heart zone, and energy expenditure 82 during participation in school physical activity programming. 83 Although, the dose–response research is promising it is difficult to 84 transfer these findings directly into instructional practice. Educational 85 reform should address student health issues through the creation of 86 policy, inclusion of physical activity across the curriculum, and best 87 practice (Castelli and Beighle, 2007); however, before this can 88 happen, we need to know what frequency, intensity, time, and type Preventive Medicine xxx (2011) xxx–xxx ⁎ Corresponding author at: Department of Kinesiology & Health Education, Anna Hiss Gym 103, A2000, The University of Texas at Austin, Austin, TX 78712, USA. Fax: +1 512 471 5574. E-mail address: dcastelli@mail.utexas.edu (D.M. Castelli). YPMED-02995; No. of pages: 5; 4C: Q3 0091-7435/$ – see front matter © 2011 Published by Elsevier Inc. doi:10.1016/j.ypmed.2011.01.019 Contents lists available at ScienceDirect Preventive Medicine journal homepage: www.elsevier.com/locate/ypmed Please cite this article as: Castelli, D.M., et al., FIT Kids: Time in target heart zone and cognitive performance, Prev. Med. (2011), doi:10.1016/ j.ypmed.2011.01.019