Exercise tolerance and effects of training in young patients with cystic fibrosis and mild airway obstruction

Abstract

We evaluated the effects of an 8-week aerobic training (1 hr, three times a week) on physical performance of ten patients with cystic fibrosis (CF) (median age, 12.5 yr; range 11.1-15.3 yr), with mild airway obstruction (FEV1 = 77 +/- 22% pred.), and ten healthy age-matched children (CONTR) (median age, 12.7 yr; range 12.2-15.2 yr). Physical performance was tested with maximal incremental (MAX) and submaximal (SMAX) (fixed workload of 1.7 W/kg during 6 min) exercise tests on a cycle ergometer. These and standard spirometric and anthropometric measurements were performed at the beginning and end of a period with usual daily activity and one with the training program. The kinetics of ventilatory parameters at the onset and end of SMAX were displayed by fitting data on oxygen uptake and minute ventilation by monoexponential curves (least-squares method). At the start and the end of the training period, all children were timed for endurance run to voluntary exhaustion and for sprinting through an obstacle course. A pattern of relative hyperventilation during SMAX and of poor performance in endurance and obstacle runs were evident at the start of the training period in patients with CF. The effects of training on MAX and SMAX were small and partial; the improvement in field test performances was significant only for CF and could be attributed to improvement of skill and motivation.

Cystic fibrosis and physiological responses to exercise

“…In the first study to address this topic, Braggion and colleagues [69] reported no differences in the VO 2 kinetic response between CF patients (FEV 1 77 ± 22% predicted, age 11.1-15.3 years) and agematched controls (age 12.2-15.2 years) during 6 min of submaximal exercise equivalent to 1.7 W/kg of body mass. However, it should be noted that in this study, only a single exercise transition was employed to quantify the VO 2 response, and the modeling procedure employed did not isolate the Phase II kinetic response, which is crucial to reflect muscle O 2 consumption [62].…”

The anaerobic threshold in cystic fibrosis: Comparison of V‐slope method, lactate turn points, and Conconi test

“…3 Standardized exercise protocols of running or swimming have been shown to have beneficial effects on sputum clearance, lung function, muscle strength, aerobic endurance, and psychosocial behavior. [4][5][6][7][8] It has also been demonstrated that physical exercise is as effective in mobilizing bronchial secretions as chest physiotherapy. 9 In CF patients exercise tolerance is dependent on a variety of factors including the severity of the disease, nutritional status, the degree of airway obstruction, and hypoxemia.…”

“…[10][11][12] For this reason there is a wide range of exercise tolerance: Patients with more severe disease are hardly able to perform any exercise, while patients with mild disease might not be limited in their exercise tolerance at all. 8,12 Therefore, training protocols for CF patients must be adjusted for each individual. To be able to set up such an individual training program, it is advisable to know the anaerobic threshold (AT), which has been defined as the level of oxygen uptake during exercise above which aerobic energy production is supplemented by anaerobic mechanisms; it is reflected by an increase in lactate and lactate/pyruvate ratio in muscle and arterial blood.…”

Exercise Training in Children and Adolescents with Cystic Fibrosis: Theory into Practice

“…Longitudinal and controlled studies are required to verify training effects in association with disease progression in CF and decline in pulmonary function and peak $\dot{\text{V}}{\text{O}}_2$. Studies, documenting less or no effects after exercise training on CPF, are most likely due to a low number of study subjects, lack of a control group or lack of training supervision, and poor compliance [25, 44]. Further research is warranted to assess the effects of different training methods longitudinally (aerobic versus anaerobic training versus a combination of both training regimes).…”