Abstract
Introduction: Exercise intolerance in cystic fibrosis (CF) is due to multiple compromised mechanisms, including dynamic hyperinflation (DH). To date, although the impact of DH on exercise is recognized, little specific information about its repercussions on daily physical activity (PA) is available.
Aims and objectives: The objective of the study was to investigate the relationship between DH and PA.
Methods: Thirty-four stable adults with CF (23 males, 11 females, mean age 33.1±8.4SD yrs; 6 homozygous for delta F508; FEV1 69±19 % predicted, BMI 22.6±2.6) were studied. All patients undertook incremental cardiopulmonary exercise testing (CPET). CPET-related measurements included: minute ventilation (VE), oxygen uptake (V’O2), carbon dioxide production (V’CO2), inspiratory capacity (IC), end-expiratory lung volume (EELV) and oxygen saturation (SpO2) throughout exercise and peak. Daily PA was assessed using the SenseWear (SW) Pro3 Armband accelerometer.
Results: Patients with DH had higher levels of daily total energy expenditure (TEE), p = 0.006. We found a significant relationship between change in EELV from rest to peak exercise (Δ EELV) and both TEE (R = 0.48, p = 0.004) and activities requiring vigorous intensity (R = 0.45, p = 0.008). Oxygen saturation at peak exercise, Δ SpO2 and breathing reserve were inversely related to moderate-vigorous PA (R = - 0.47, p = 0.005; R = - 0.59, p < 0.001; R = - 0.43, p = 0.01 respectively).
Conclusions: DH is significantly related to daily PA performed by patients with mild to moderate CF. The occurrence of DH during CPET did not impact the level of daily PA and can only inform the clinicians whether exercise tolerance is limited by ventilatory mechanisms.
- Copyright ©the authors 2017