Maximal work capacity in relation to nutritional status in children with cystic fibrosis

Abstract

In children with cystic fibrosis, objective parameters of exercise tolerance are needed which are easy to measure in nonspecialized centres. We investigated maximal workload (W 'max) in children with cystic fibrosis in relation to body weight and fat-free mass, and compared this with results for maximal oxygen consumption (V 'O 2 ,max).Fourteen patients with cystic fibrosis performed an incremental maximal exercise test on a bicycle ergometer. W 'max, V 'O 2 ,max, body weight and fat-free mass were measured.W 'max and V 'O 2 ,max were significantly correlated (r=0.91; p<0.001). Using standard deviation scores in relation to reference values, W 'max and V 'O 2 ,max per kilogram body weight were significantly higher than uncorrected W 'max and V 'O 2 ,max (mean difference (95% CI) 0.63 (0.24-1.01) and 0.91 (0.32-1.49) SD units, respectively). There was no such difference after correction for fat-free mass. Standardized V 'O 2 ,max was significantly higher than standardized W 'max (mean difference (95% CI): 1.59 (1.14-2.04)), also after correction for body weight and fat-free mass.In children with mild-to-moderate cystic fibrosis, maximal workload per kilogram fat-free mass, but not per kilogram body weight, is a useful parameter to correct for diminished nutritional status. In these patients, maximal workload is consistently lower than maximal oxygen consumption. Taking into account this difference, maximal workload and maximal workload per kilogram fat-free mass can be used for follow-up of paediatric patients with cystic fibrosis in nonspecialized settings.

Skinfold measurements in children with cystic fibrosis: monitoring fat-free mass and exercise effects

“…Exercise programmes have been shown to improve exercise tolerance in adults and children with CF [1,4,20,30]. Nutritional status and exercise tolerance in CF patients are associated with prognosis and survival [6,19], and preservation of nutritional status and exercise tolerance is therefore important [12,13,25]. Longitudinal monitoring of weight and FFM evaluates the potential bene®ts (e.g.…”

Reduced exercise capacity in non-cystic fibrosis bronchiectasis

“…6,7 Patients with CF have diminished work capacity and an increased oxygen cost of exercise. 13 Muscle weakness and low fat free body mass are associated with decreased physical performance; FVC and FEV 1 were also shown to correlate with Wmax and VO 2 max in patients with moderate CF but not in children with mild CF or in healthy children. 14 In the present study, though the BMI of patients was lower than that predicted for age, it did not contribute towards the reduction in VO 2 max (r=0.03), suggesting that malnutrition was not primarily responsible for exercise limitation.…”

Limiting factors in peak oxygen uptake and the relationship with functional ambulation in ambulating children with Spina Bifida

“…Gas exchange analysis during an incremental ergometry test to the point of volitional termination due to exhaustion is considered the gold standard to measure VO 2peak (Shephard et al 1968). Earlier studies employing exercise testing in healthy children show it is possible to test VO 2peak in healthy children (Armstrong et al 1996;Eiberg et al 2005;Gulmans et al 1997;Reybrouck et al 1992;Rowland 1993). In this study, VO 2peak was measured using a treadmill test (EnMill, Enraf, Delft, The Netherlands), since all children would be able to perform this test and reference values are available for both young children and adolescents.…”