title: The correlates of body composition with heart rate recovery after step test: an exploratory study of Malaysian adolescents.
abstract: BACKGROUND
  In adults, heart rate recovery is a predictor of mortality, while in adolescents it is associated with cardio-metabolic risk factors. The aim of this study was to examine the relationship between body composition measures and heart rate recovery (HRR) after step test in Malaysian secondary school students.
  
  
  METHODS
  In the Malaysian Health and Adolescents Longitudinal Research Team (MyHEART) study, 1071 healthy secondary school students, aged 13 years old, participated in the step test. Parameters for body composition measures were body mass index z-score, body fat percentage, waist circumference, and waist height ratio. The step test was conducted by using a modified Harvard step test. Heart rate recovery of 1 minute (HRR1min) and heart rate recovery of 2 minutes (HRR2min) were calculated by the difference between the peak pulse rate during exercise and the resting pulse rate at 1 and 2 minutes, respectively. Analysis was done separately based on gender. Pearson correlation analysis was used to determine the association between the HRR parameters with body composition measures, while multiple regression analysis was used to determine which body composition measures was the strongest predictor for HRR.
  
  
  RESULTS
  For both gender groups, all body composition measures were inversely correlated with HRR1min. In girls, all body composition measures were inversely correlated with HRR2min, while in boys all body composition measures, except BMI z-score, were associated with HRR2min. In multiple regression, only waist circumference was inversely associated with HRR2min (p=0.024) in boys, while in girls it was body fat percentage for HRR2min (p=0.008).
  
  
  CONCLUSIONS
  There was an inverse association between body composition measurements and HRR among apparently healthy adolescents. Therefore, it is important to identify cardio-metabolic risk factors in adolescent as an early prevention of consequent adulthood morbidity. This reiterates the importance of healthy living which should start from young.
authors.affiliation: Sports Medicine Unit, Faculty of Medicine, University Malaya, Kuala Lumpur, Malaysia.
authors.forename: Redzal
authors.initials: R
authors.lastname: Abu Hanifah
authors.affiliation: Sports Medicine Unit, Faculty of Medicine, University Malaya, Kuala Lumpur, Malaysia.
authors.forename: Mohd Nahar Azmi
authors.initials: MN
authors.lastname: Mohamed
authors.affiliation: Sports Medicine Unit, Faculty of Medicine, University Malaya, Kuala Lumpur, Malaysia.
authors.forename: Zulkarnain
authors.initials: Z
authors.lastname: Jaafar
authors.affiliation: Centre for Population Health (CePH), Department of Social and Preventive Medicine, Faculty of Medicine, University Malaya, Kuala Lumpur, Malaysia.
authors.forename: Nabilla Al-Sadat Abdul
authors.initials: NA
authors.lastname: Mohsein
authors.affiliation: Department of Paediatrics, Faculty of Medicine, University Malaya, Kuala Lumpur, Malaysia.
authors.forename: Muhammad Yazid
authors.initials: MY
authors.lastname: Jalaludin
authors.affiliation: Centre for Population Health (CePH), Department of Social and Preventive Medicine, Faculty of Medicine, University Malaya, Kuala Lumpur, Malaysia.
authors.forename: Hazreen Abdul
authors.initials: HA
authors.lastname: Majid
authors.affiliation: Centre for Public Health, School of Medicine, Dentistry and Biomedical Science, Queen's University, Belfast, Northern Ireland.
authors.forename: Liam
authors.initials: L
authors.lastname: Murray
authors.affiliation: Centre for Public Health, School of Medicine, Dentistry and Biomedical Science, Queen's University, Belfast, Northern Ireland.
authors.forename: Marie
authors.initials: M
authors.lastname: Cantwell
authors.affiliation: Centre for Population Health (CePH), Department of Social and Preventive Medicine, Faculty of Medicine, University Malaya, Kuala Lumpur, Malaysia.
authors.forename: Tin Tin
authors.initials: TT
authors.lastname: Su
mesh_terms: D000293:Adolescent; D000328:Adult; D001823:Body Composition / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008296:Malaysia; D008297:Male; D012737:Sex Factors; D013997:Time Factors