Open Access Highly Accessed Research article

Quality of life is associated with physical activity and fitness in cystic fibrosis

Helge Hebestreit18*, Kerstin Schmid1, Stephanie Kieser1, Sibylle Junge2, Manfred Ballmann3, Kristina Roth1, Alexandra Hebestreit1, Thomas Schenk4, Christian Schindler5, Hans-Georg Posselt6 and Susi Kriemler57

Author Affiliations

1 Pediatric Department, University of Würzburg, Würzburg, Germany

2 Pediatric Pulmonology and Neonatology, Hannover Medical School, Hannover, Germany

3 St Josef Hospital Pediatric Clinic, Ruhr University Bochum, Bochum, Germany

4 Department of Anaesthesiology, University of Würzburg, Würzburg, Germany

5 Swiss Tropical and Public Health Institute, University of Basel, Basel, Switzerland

6 Pediatric Department, Johann Wolfgang Goethe University, Frankfurt, Germany

7 Institute for Social and Preventive Medicine, University of Zürich, Zürich, Switzerland

8 Universitäts-Kinderklinik, Josef-Schneider-Str. 2, 97080 Würzburg, Germany

For all author emails, please log on.

BMC Pulmonary Medicine 2014, 14:26  doi:10.1186/1471-2466-14-26

Published: 27 February 2014



Health-related and disease-specific quality of life (HRQoL) has been increasingly valued as relevant clinical parameter in cystic fibrosis (CF) clinical care and clinical trials. HRQoL measures should assess – among other domains – daily functioning from a patient’s perspective. However, validation studies for the most frequently used HRQoL questionnaire in CF, the Cystic Fibrosis Questionnaire (CFQ), have not included measures of physical activity or fitness. The objective of this study was, therefore, to determine the cross-sectional and longitudinal relationships between HRQoL, physical activity and fitness in patients with CF.


Baseline (n = 76) and 6-month follow-up data (n = 70) from patients with CF (age ≥12 years, FEV1 ≥35%) were analysed. Patients participated in two multi-centre exercise intervention studies with identical assessment methodology. Outcome variables included HRQoL (German revised multi-dimensional disease-specific CFQ (CFQ-R)), body composition, pulmonary function, physical activity, short-term muscle power, and aerobic fitness by peak oxygen uptake and aerobic power.


Peak oxygen uptake was positively related to 7 of 13 HRQoL scales cross-sectionally (r = 0.30-0.46). Muscle power (r = 0.25-0.32) and peak aerobic power (r = 0.24-0.35) were positively related to 4 scales each, and reported physical activity to 1 scale (r = 0.29). Changes in HRQoL-scores were directly and significantly related to changes in reported activity (r = 0.35-0.39), peak aerobic power (r = 0.31-0.34), and peak oxygen uptake (r = 0.26-0.37) in 3 scales each. Established associates of HRQoL such as FEV1 or body mass index correlated positively with fewer scales (all 0.24 < r < 0.55).


HRQoL was associated with physical fitness, especially aerobic fitness, and to a lesser extent with reported physical activity. These findings underline the importance of physical fitness for HRQoL in CF and provide an additional rationale for exercise testing in this population.

Trial registration, NCT00231686

Exercise testing; Oxygen uptake; Longitudinal analysis; Accelerometry; Questionnaire