Fit or Unfit: Are overweight and obese children and adolescents really unfit or are we using the wrong assessment tools?

  • Miss Astrid De Souza, Division of Cardiology, Department of Pediatrics, British Columbia Children's Hospital and The University of British Columbia, Canada
  • Dr Kristin Houghton, Division of Rheumatology, Department of Pediatrics, British Columbia Children's Hospital and The University of British Columbia, Canada
  • Dr Mary Hinchliffe, Shapedown Program at the Centre for Healthy Weights, British Columbia Children's Hospital, Canada
  • Dr Shubhayan Sanatani, Division of Cardiology, Department of Pediatrics, British Columbia Children's Hospital and The University of British Columbia, Canada
  • Dr Walter Duncan, Division of Cardiology, Department of Pediatrics, British Columbia Children's Hospital and The University of British Columbia, Canada
  • Dr Derek Human, Division of Cardiology, Department of Pediatrics, British Columbia Children's Hospital and The University of British Columbia, Canada
  • Dr George Sandor, Division of Cardiology, Department of Pediatrics, British Columbia Children's Hospital and The University of British Columbia, Canada
  • Dr James Potts, Division of Cardiology, Department of Pediatrics, British Columbia Children's Hospital and The University of British Columbia, Canada

    • BACKGROUND: Assessment of physical fitness is important in the management of overweight and obese children to modify long-term cardiovascular risk. Fitness has been shown to be lower in these children; however, the degree of impairment is unclear. VO2peak is obtained from a maximal cardiopulmonary exercise test (CPX), but this method is expensive and requires technical expertise. The six minute walk test (6MWT), a submaximal test, can be used to predict VO2peak, is easy to conduct, and requires minimal equipment. There are no data for the 6MWT in this population. OBJECTIVE: To determine the fitness of a cohort of overweight and obese children using a CPX and a 6MWT. METHODS: We studied 81 patients (46 male) between the ages of 9-17 years. All patients completed a treadmill CPX test. The 6MWT was completed by 49 patients. Results were compared to published normals. RESULTS: All males and 97% of females had a median z-score within (± 2 SD) or above the normal range for absolute VO2peak (males=1.0; females=1.4). Median relative VO2peak z-score was -1.8 for both males and females, with 63% and 60% within the normal range. Using the 6MWT, 65% of males and 86% of females had a walking distance below the normal range. CONCLUSION: The CPX test suggests that a large proportion of overweight and obese children have normal fitness levels, while the submaximal 6MWT suggests that a large percentage are unfit. Depending on how fitness is assessed, these children may appear above, within, or below the normal range.