title: Breakfast glycaemic index and exercise: combined effects on adolescents' cognition.
abstract: The aim of the present study was to examine the combined effects of breakfast glycaemic index (GI) and a mid-morning bout of exercise on adolescents' cognitive function. Participants were randomly allocated to a high or low GI breakfast group in a mixed research design, where each participant completed two experimental trials (exercise and resting). Forty-two adolescents (12.4±0.5 years old), undertook a bout of exercise (ten repeats of level one of the multi-stage fitness test; exercise trial) or continued to rest (resting trial) following consumption of either a high or low GI breakfast. A battery of cognitive function tests (visual search test, Stroop test and Sternberg paradigm) was completed 30 min before and 45 min following the exercise. Average heart rate during exercise was 170±15 beats·min(-1). On the complex level of the Stroop test, response times improved across the morning following the low GI breakfast on both the exercise and resting trials, though the improvement was greatest on the exercise trial. However, response times only improved on the resting trial following the high GI breakfast (p=0.012). On the 5 letter level of the Sternberg paradigm, response times improved across the morning following the low GI breakfast (regardless of exercise) and only on the exercise trial following the high GI breakfast (p=0.019). The findings of the present study suggest that the combined effects of breakfast GI and exercise in adolescents depend upon the component of cognitive function examined. A low GI breakfast and mid-morning bout of exercise were individually beneficial for response times on the Sternberg paradigm, whereas they conferred additional benefits for response times on the Stroop test.
authors.affiliation: Sport, Health & Performance Enhancement (SHAPE) Research Group, Sport Science Department, School of Science and Technology, Nottingham Trent University, Nottingham, NG11 8NS, United Kingdom. Electronic address: Simon.Cooper@ntu.ac.uk.
authors.forename: Simon B
authors.initials: SB
authors.lastname: Cooper
authors.affiliation: Institute of Youth Sport, School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire, LE11 3TU, United Kingdom. Electronic address: S.Bandelow@lboro.ac.uk.
authors.forename: Stephan
authors.initials: S
authors.lastname: Bandelow
authors.affiliation: Institute of Youth Sport, School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire, LE11 3TU, United Kingdom. Electronic address: M.L.Nute@lboro.ac.uk.
authors.forename: Maria L
authors.initials: ML
authors.lastname: Nute
authors.affiliation: Sport, Health & Performance Enhancement (SHAPE) Research Group, Sport Science Department, School of Science and Technology, Nottingham Trent University, Nottingham, NG11 8NS, United Kingdom. Electronic address: John.Morris@ntu.ac.uk.
authors.forename: John G
authors.initials: JG
authors.lastname: Morris
authors.affiliation: Sport, Health & Performance Enhancement (SHAPE) Research Group, Sport Science Department, School of Science and Technology, Nottingham Trent University, Nottingham, NG11 8NS, United Kingdom. Electronic address: Mary.Nevill@ntu.ac.uk.
authors.forename: Mary E
authors.initials: ME
authors.lastname: Nevill
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D001786:Blood Glucose; D062408:Breakfast; D003071:Cognition / Q000187:drug effects* / Q000502:physiology*; D004040:Dietary Carbohydrates / Q000378:metabolism / Q000494:pharmacology*; D004644:Emotions / Q000187:drug effects; D015444:Exercise / Q000502:physiology*; D005260:Female; D038321:Glycemic Index; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D011930:Reaction Time / Q000187:drug effects; D011795:Surveys and Questionnaires
chemical_list: D001786:Blood Glucose; D004040:Dietary Carbohydrates
keywords: Acute exercise; Attention; Breakfast glycaemic index; Visual search; Working memory; Youth