title: Optimal level of physical activity in children with chronic lung diseases.
abstract: OBJECTIVE
  To determine the optimal level of physical activity and its relationship with disease severity in children with chronic lung diseases (CLD).
  
  
  METHODS
  Pulmonary function and exercise tests were compared between 18 CLD children (aged 13.5 +/- 2.4 years, 33% male) and 18 healthy controls without any history of lung diseases (age and sex matched).
  
  
  RESULTS
  CLD children had lower forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV)(1), forced expiratory flow rate between 25% and 75% of vital capacity (FEF)(25-75%) and total lung capacity (TLC) and higher residual volume (RV)/TLC ratio than controls (77.3 +/- 22.6 vs. 97.9 +/- 12.5%pred; p = 0.002, 74.3 +/- 17.6 vs. 104.0 +/- 12.6%pred; p < 0.001, 49.9 +/- 23.1 vs. 75.6 +/- 18.6%pred; p < 0.001, 82.8 +/- 18.6 vs. 95.6 +/- 9.8%pred; p = 0.04, 30.8 +/- 10.2 vs. 24.4 +/- 5.9%; p = 0.04, respectively). Oxygen consumption at anaerobic threshold (AT) and optimal level of physical activity (metabolic equivalents [METs] at AT) were not different between the two groups and between mild and moderate to severe CLD. However, when the exercise was continued beyond the AT, CLD children demonstrated poorer exercise performance than normal controls.
  
  
  CONCLUSIONS
  Children with CLD demonstrated the same level of optimal physical activity as normal children despite their lower lung function. The optimal level of physical activity was not related to disease severity. The exercise test and exercise should not be performed beyond the AT by the CLD children. Proper exercise test should be done to determine their optimal exercise activity.
authors.affiliation: Division of Pulmonology and Critical Care, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand. suchadacu@hotmail.com
authors.forename: Suchada
authors.initials: S
authors.lastname: Sritippayawan
authors.forename: Chanthana
authors.initials: C
authors.lastname: Harnruthakorn
authors.forename: Jitladda
authors.initials: J
authors.lastname: Deerojanawong
authors.forename: Rujipat
authors.initials: R
authors.lastname: Samransamruajkit
authors.forename: Nuanchan
authors.initials: N
authors.lastname: Prapphal
mesh_terms: D000293:Adolescent; D016022:Case-Control Studies; D002648:Child; D002908:Chronic Disease; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006801:Humans; D008171:Lung Diseases / Q000503:physiopathology*; D008297:Male; D012129:Respiratory Function Tests