title: Relationship between daily physical activity and aerobic fitness in adults with cystic fibrosis.
abstract: BACKGROUND
  The best clinical practice to investigate aerobic fitness includes measurements obtained during cardiopulmonary exercise testing (CPET), however it remains an underutilised clinical measure in cystic fibrosis (CF). To investigate this further, different methods of quantifying exercise capacity in CF are required. The possibility that measuring physical activity (PA) by a portable accelerometer could be used to assess the CF aerobic state and could be added among the CPET surrogates has not been investigated. The aim of this study was to examine the relationship between PA and exercise fitness both at submaximal and maximal levels in clinically stable adults with CF.
  
  
  METHODS
  Thirty CF patients (FEV1 71 ± 19% predicted) and fifteen healthy controls undertook an incremental CPET on a cycle ergometer. CPET-related measurements included: oxygen uptake (V'O2), carbon dioxide production (V'CO2), ventilatory profile, heart rate (HR) and oxygen pulse (V'O2/HR) throughout exercise and at lactic threshold (LT) and peak. LT measures represent submaximal exercise related data. PA was assessed using the accelerometer SenseWear Pro3 Armband.
  
  
  RESULTS
  Moderate (>4.8 metabolic equivalents (METS)) and moderate + vigorous (>7.2 METS) PA was related to V'O2 (p = 0.005 and p = 0.009, respectively) and work rate (p = 0.004 and p = 0.002, respectively) at LT. Moderate PA or greater was positively related to peak V'O2 (p = 0.005 and p = 0.003, respectively). Daily PA levels were similar in CF and healthy controls. Except for peak values, V'O2 profile and the V'O2 at LT were comparable between CF and healthy controls.
  
  
  CONCLUSIONS
  In adult CF patients daily PA positively correlated with aerobic capacity. PA measurements are a valuable tool in the assessment of exercise performance in an adult CF population and could be used for interventional exercise trials to optimize exercise performance and health status. PA levels and parameters obtained at submaximal exercise are similar in CF and in healthy controls.
authors.affiliation: Department of Pediatrics and Pediatric Neurology, Cystic Fibrosis Center, Sapienza University of Rome, 00185, Rome, Italy. danielasavi1@virgilio.it.
authors.forename: Daniela
authors.initials: D
authors.lastname: Savi
authors.affiliation: Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185, Rome, Italy. marcello.dp@hotmail.com.
authors.forename: Marcello
authors.initials: M
authors.lastname: Di Paolo
authors.affiliation: Department of Cystic Fibrosis, Royal Brompton Hospital and Imperial College, SW3 6NP, London, UK. N.Simmonds@rght.nhs.uk.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Simmonds
authors.affiliation: Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185, Rome, Italy. onoratip68@gmail.com.
authors.forename: Paolo
authors.initials: P
authors.lastname: Onorati
authors.affiliation: Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185, Rome, Italy. m.internullo@virgilio.it.
authors.forename: Mattia
authors.initials: M
authors.lastname: Internullo
authors.affiliation: Department of Pediatrics and Pediatric Neurology, Cystic Fibrosis Center, Sapienza University of Rome, 00185, Rome, Italy. serena.quattrucci@uniroma1.it.
authors.forename: Serena
authors.initials: S
authors.lastname: Quattrucci
authors.affiliation: NIHR Respiratory BRU, Royal Brompton Hospital NHS Foundation Trust, SW3 6NP, London, UK. w.banya@imperial.ac.uk.
authors.forename: Banya
authors.initials: B
authors.lastname: Winston
authors.affiliation: Neurophysiologie Respiratoire Expérimentale et Clinique, Sorbonne Universités, UPMC University Paris 06, UMR_S, 1158 75005, Paris, France. pier_lav@yahoo.it.|Neurophysiologie Respiratoire Expérimentale et Clinique, INSERM, UMR_S, 1158 75005, Paris, France. pier_lav@yahoo.it.|AP-HP, Groupe Hospitalier Pitié-Salpêtrière Charles Foix, Service des Explorations Fonctionnelles de la Respiration, de l'Exercice et de la Dyspnée, 75013, Paris, France. pier_lav@yahoo.it.
authors.forename: Pierantonio
authors.initials: P
authors.lastname: Laveneziana
authors.affiliation: Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185, Rome, Italy. paolo.palange@uniroma1.it.|Eleonora Lorrillard-Spencer Cenci Foundation, Rome, Italy. paolo.palange@uniroma1.it.
authors.forename: Paolo
authors.initials: P
authors.lastname: Palange
mesh_terms: D061725:Accelerometry; D000328:Adult; D002245:Carbon Dioxide / Q000378:metabolism; D016022:Case-Control Studies; D003550:Cystic Fibrosis / Q000503:physiopathology*; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D055686:Metabolic Equivalent; D009043:Motor Activity / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology*; D010809:Physical Fitness; D012123:Pulmonary Ventilation / Q000502:physiology
chemical_list: D002245:Carbon Dioxide