Physical activity is independently related to aerobic capacity in cystic fibrosis

¹ University Children's Hospital, Julius-Maximilians-Universität Würzburg, Germany
² Pediatric Department, Medizinische Hochschule Hannover, Germany
³ Pediatric Department, Johann Wolfgang Goethe Universität, Frankfurt, Germany
⁴ Exercise Physiology, Swiss Federal Institute of Technology and University of Zurich, Switzerland

^* To whom correspondence should be addressed. E-mail: hebestreit{at}mail.uni-wuerzburg.de.

	Abstract

It is unclear whether a relationship between physical activity (PA) and peak oxygen uptake (VO₂peak) exists in cystic fibrosis (CF) and, if so, whether the relationship reflects a direct effect or is mediated by the effects of confounding variables such as pulmonary or muscle function. The objective of this study was, therefore, to determine the relationship between PA and VO₂peak in CF while adjusting for possible influences of confounding factors.

We studied 36 female and 35 male patients with CF from Germany and Switzerland (12-40 yrs., FEV1 25-107%predicted). A Wingate test was employed to measure muscle power. PA was monitored for 7 days using the MTI/CSA 7164 accelerometer and expressed in two ways, average daily accelerometer count (ADAC) and time spent in moderate to vigorous PA (MVPA). VO₂peak was determined during an incremental cycle exercise test to volitional fatigue.

PA was positively related to VO₂peak. In a multiple linear regression analysis, height, gender, FEV1, muscle power, and ADAC (additionally explained variance2.5%) or time spent in MVPA (additionally explained variance 3.7%) were identified as independent predictors of VO₂peak.

In conclusion, high levels of PA in addition to good muscular and pulmonary functions are associated with a high aerobic capacity in CF.

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