Intensity of daily activity may affect exercise capacity and peripheral muscle function in adults with cystic fibrosis

ABSTRACT Introduction. Data obtained in young cystic fibrosis (CF) patients suggest that daily physical activity (PA) may have a positive impact on exercise tolerance, on nutritional status and on the rate of decline of FEV1. There is also evidence that in CF patients improving physical activity increases sputum clearance, improves respiratory muscle strength and ultimately leads to better quality of life. To date, less is known in adult patients about the role that physical activity intensity play to the patients’ functional status. Methods. Twenty stable CF patients (mean age 33±8SD yrs; FEV1 2.6±0.6 l; FEV1 68±16 % predicted, BMI 22±2) were studied at rest and during symptom-limited incremental exercise test (CPET). We measured hand-grip strength using a hydraulic hand dynamometer and we assessed daily physical activity using SenseWear (SW) accelerometer that subjects wore for 5 consecutive days from waking until going to bed. Results. We found a good relationship between SW a

ABSTRACT Introduction. Data obtained in young cystic fibrosis (CF) patients suggest that daily physical activity (PA) may have a positive impact on exercise tolerance, on nutritional status and on the rate of decline of FEV1. There is also evidence that in CF patients improving physical activity increases sputum clearance, improves respiratory muscle strength and ultimately leads to better quality of life. To date, less is known in adult patients about the role that physical activity intensity play to the patients’ functional status. Methods. Twenty stable CF patients (mean age 33±8SD yrs; FEV1 2.6±0.6 l; FEV1 68±16 % predicted, BMI 22±2) were studied at rest and during symptom-limited incremental exercise test (CPET). We measured hand-grip strength using a hydraulic hand dynamometer and we assessed daily physical activity using SenseWear (SW) accelerometer that subjects wore for 5 consecutive days from waking until going to bed. Results. We found a good relationship between SW activities of moderate intensity vs V’O2peak (r=0.5; p=0.02) and vs V’E peak (r=0.436, p=0.05) measured at CPET. A close relathionship was observed between vigorous SW activities and both V’O2peak and Watt max (r=0.545; p=0.01; (r=0.547, p=0.01). There was a good relationship between hand-grip strength and SW daily physical activity of moderate (r=0.431; p=0.05) and vigorous (r=0.508; p=0.02) intensity. SW mild physical activity was not correlated to muscle and exercise variables. Conclusions: In adult CF patients with mild to moderate lung obstruction, PA levels of moderate intensity and above are strongly related to exercise capacity. Specifically, only daily life activity above moderate intensity seems to maintain physical fitness and peripheral muscle function. Encouraging exercise of moderate intensity to be a part of the therapy is important.