title: Recommended levels and intensities of physical activity to avoid low-cardiorespiratory fitness in European adolescents: The HELENA study.
abstract: OBJECTIVE
  The purpose of this study was to determine the sex-specific physical activity (PA) intensity thresholds that best discriminate between unhealthy/healthy cardiorespiratory fitness (CRF).
  
  
  METHODS
  Participants included 1,808 adolescents (964 girls), aged 12.5-17.5 years, from the HELENA study. We measured PA by accelerometer and calculated the time spent at light, moderate, vigorous, and moderate-to-vigorous (MVPA) intensities. CRF was assessed by the 20-m shuttle-run test. Adolescents were dichotomized (unhealthy/healthy) based on sex- and age-specific FITNESSGRAM standards. Receiver operating characteristic (ROC) analysis was used to determine thresholds that best discriminate between CRF categories.
  
  
  RESULTS
  ROC analyses revealed that the PA thresholds that best discriminate between unhealthy/healthy CRF were ≥152, ≥33, ≥13, and ≥52 min/day in light, moderate, vigorous, and MVPA, respectively. In boys, the PA thresholds associated with a healthy CRF were ≥37, ≥19, and ≥56 min/day in moderate, vigorous, and MVPA, respectively, whereas in girls were ≥152, ≥34, ≥12, and ≥51 min/day in light, moderate, vigorous, and MVPA, respectively. Spending at least 60 min/day in MVPA was also associated with a healthy CRF (odds ratios: 1.75, 1.94, and 1.57, all P < 0.05, for the whole sample, boys, and girls, respectively).
  
  
  CONCLUSIONS
  This study shows sex- and intensity-specific PA thresholds to discriminate between adolescents with a healthy CRF from those with a less favorable or unhealthy CRF level.
authors: Unit for Preventive Nutrition, Department of Biosciences and Nutrition at NOVUM, Karolinska Institutet, Huddinge, Sweden.
authors: David
authors: D
authors: Martinez-Gomez
authors: Jonatan R
authors: JR
authors: Ruiz
authors: Francisco B
authors: FB
authors: Ortega
authors: Jose A
authors: JA
authors: Casajús
authors: Oscar L
authors: OL
authors: Veiga
authors: Kurt
authors: K
authors: Widhalm
authors: Yannis
authors: Y
authors: Manios
authors: Laurent
authors: L
authors: Béghin
authors: Marcela
authors: M
authors: González-Gross
authors: Anthony
authors: A
authors: Kafatos
authors: Vanesa
authors: V
authors: España-Romero
authors: Denes
authors: D
authors: Molnar
authors: Luis A
authors: LA
authors: Moreno
authors: Ascension
authors: A
authors: Marcos
authors: Manuel J
authors: MJ
authors: Castillo
authors: Michael
authors: M
authors: Sjöström
mesh_terms: D000293:Adolescent; D001837:Body Weights and Measures; D005060:Europe; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D010101:Oxygen Consumption; D010809:Physical Fitness; D012737:Sex Factors