title: The effects of time and intensity of exercise on novel and established markers of CVD in adolescent youth.
abstract: OBJECTIVE
  This article examines the effects of brief, intense exercise in comparison with traditional endurance exercise on both novel and traditional markers of cardiovascular disease (CVD) in youth.
  
  
  METHODS
  Forty seven boys and ten girls (16.4 ± 0.7 years of age) were divided into a moderate (MOD), high intensity (HIT), or a control group. The MOD group (12 boys, 4 girls) and HIT group (15 boys, 2 girls) performed three weekly exercise sessions over 7 weeks. Each session consisted of either four to six repeats of maximal sprint running within a 20 m area with 20-30 s recovery (HIT) or 20 min continuous running within a 20 m area at ∼70% maximal oxygen uptake (VO(2) max).
  
  
  RESULTS
  Total exercise time commitment over the intervention was 420 min (MOD) and 63 min (HIT). Training volume was 85% lower for the HIT group. Total estimated energy expenditure was ∼907.2 kcal (HIT) and ∼4410 kcal (MOD). Significant improvements (P ≤ 0.05) were found in systolic blood pressure, aerobic fitness, and body mass index (BMI) postintervention (HIT). In the MOD group, significant (P ≤ 0.05) improvements were noted in aerobic fitness, percentage body fat (%BF), BMI, fibrinogen (Fg), plasminogen activator inhibitor-1, and insulin concentrations.
  
  
  CONCLUSIONS
  These findings demonstrate that brief, intense exercise is a time efficient means for improving CVD risk factors in adolescents.
authors.affiliation: Health and Exercise Sciences, School of Science, University of the West of Scotland, Hamilton, United Kingdom. duncan.buchan@uws.ac.uk
authors.forename: Duncan S
authors.initials: DS
authors.lastname: Buchan
authors.forename: Stewart
authors.initials: S
authors.lastname: Ollis
authors.forename: John D
authors.initials: JD
authors.lastname: Young
authors.forename: Non E
authors.initials: NE
authors.lastname: Thomas
authors.forename: Stephen-Mark
authors.initials: SM
authors.lastname: Cooper
authors.forename: Tom K
authors.initials: TK
authors.lastname: Tong
authors.forename: Jinlei
authors.initials: J
authors.lastname: Nie
authors.forename: Robert M
authors.initials: RM
authors.lastname: Malina
authors.forename: Julien S
authors.initials: JS
authors.lastname: Baker
mesh_terms: D000273:Adipose Tissue; D000293:Adolescent; D000367:Age Factors; D000704:Analysis of Variance; D015415:Biomarkers; D001794:Blood Pressure; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000517:prevention & control*; D004734:Energy Metabolism; D015444:Exercise / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007249:Inflammation / Q000097:blood; D015850:Interleukin-6 / Q000097:blood; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology; D010809:Physical Fitness / Q000502:physiology*; D012885:Skinfold Thickness; D011795:Surveys and Questionnaires; D013997:Time Factors
chemical_list: D015415:Biomarkers; D015850:Interleukin-6