title: Exercise training improves breathing strategy and performance during the six-minute walk test in obese adolescents.
abstract: OBJECTIVE
  We aimed to examine ventilatory responses during the six-minute walk test in healthy-weight and obese adolescents before and after exercise training.
  
  
  METHODS
  Twenty obese adolescents (OB) (age: 14.5±1.7 years; BMI: 34.0±4.7kg·m(-2)) and 20 age and gender-matched healthy-weight adolescents (HW) (age: 15.5±1.5 years; BMI: 19.9±1.4kg·m(-2)) completed six-minute walk test during which breath-by-breath gas analysis and expiratory flow limitation (expFL) were measured. OB participated in a 12-week exercise-training program.
  
  
  RESULTS
  Comparison between HW and OB participants showed lower distance achieved during the 6MWT in OB (-111.0m, 95%CI: -160.1 to 62.0, p<0.05) and exertional breathlessness was greater (+0.78 a.u., 95%CI: 0.091-3.27, p=0.039) when compared with HW. Obese adolescents breathed at lower lung volumes, as evidenced by lower end expiratory and end inspiratory lung volumes during exercise (p<0.05). Prevalence of expFL (8 OB vs 2 HW, p=0.028) and mean expFL (14.9±21.9 vs 5.32±14.6% VT, p=0.043, in OB and HW) were greater in OB. After exercise training, mean increase in the distance achieved during the 6MWT was 64.5 meters (95%CI: 28.1-100.9, p=0.014) and mean decrease in exertional breathlessness was 1.62 (95%CI: 0.47-2.71, p=0.05). Obese adolescents breathed at higher lung volumes, as evidenced by the increase in end inspiratory lung volume from rest to 6-min exercise (9.9±13.4 vs 20.0±13.6%TLC, p<0.05). Improved performance was associated with improved change in end inspiratory lung volume from rest to 6-min exercise (r=0.65, p=0.025).
  
  
  CONCLUSIONS
  Our results suggest that exercise training can improve breathing strategy during submaximal exercise in obese adolescents and that this increase is associated with greater exercise performance.
authors.affiliation: Uni. Grenoble Alpes, HP2, F-38000 Grenoble, France; INSERM, HP2, F-38000 Grenoble, France; CHU de Grenoble, HP2, F-38000 Grenoble, France. Electronic address: moniquemendelson1@gmail.com.
authors.forename: Monique
authors.initials: M
authors.lastname: Mendelson
authors.affiliation: Uni. Grenoble Alpes, HP2, F-38000 Grenoble, France; INSERM, HP2, F-38000 Grenoble, France; CHU de Grenoble, HP2, F-38000 Grenoble, France.
authors.forename: Anne-Sophie
authors.initials: AS
authors.lastname: Michallet
authors.affiliation: Grenoble University Hospital, Pediatrics Department, F-38000 Grenoble, France.
authors.forename: Claudine
authors.initials: C
authors.lastname: Perrin
authors.affiliation: Uni. Grenoble Alpes, HP2, F-38000 Grenoble, France; INSERM, HP2, F-38000 Grenoble, France; CHU de Grenoble, HP2, F-38000 Grenoble, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Levy
authors.affiliation: Uni. Grenoble Alpes, HP2, F-38000 Grenoble, France; INSERM, HP2, F-38000 Grenoble, France; CHU de Grenoble, HP2, F-38000 Grenoble, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Wuyam
authors.affiliation: Uni. Grenoble Alpes, HP2, F-38000 Grenoble, France; INSERM, HP2, F-38000 Grenoble, France; CHU de Grenoble, HP2, F-38000 Grenoble, France.
authors.forename: Patrice
authors.initials: P
authors.lastname: Flore
mesh_terms: D000293:Adolescent; D001944:Breath Tests; D004417:Dyspnea / Q000503:physiopathology / Q000534:rehabilitation; D005080:Exercise Test; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008176:Lung Volume Measurements; D008297:Male; D009765:Obesity / Q000503:physiopathology* / Q000534:rehabilitation*; D010101:Oxygen Consumption / Q000502:physiology; D005082:Physical Exertion / Q000502:physiology; D012123:Pulmonary Ventilation / Q000502:physiology; D012119:Respiration; D013990:Tidal Volume / Q000502:physiology; D016896:Treatment Outcome; D016138:Walking / Q000502:physiology*
keywords: Adolescent; Breathing strategy; Exercise training; Obesity; Six-minute walk test