Energy metabolism during anaerobic exercise in children with cystic fibrosis and asthma

The Comparison of Anaerobic Power using Two Tests in Patients with Cystic Fibrosis and Healthy Children

ABSTRACT Purpose: Cystic fibrosis (CF), a progressive and multi-systemic disease, causes reduced anaerobic performance. This study aimed to compare anaerobic power using two tests (Counter-movement Vertical Jump and Wingate Anaerobic Test) in CF patients and healthy children. Material and Methods: Eighteen CF and 18 healthy children were included in this prospective study. Knee extensor muscle strength and body composition were assessed with a digital handheld dynamometer and Tanita-BC 418, respectively. Anaerobic power was evaluated with Wingate Anaerobic Test (WAnT) and Counter-movement Vertical Jump (CMJ) using a triaxial accelerometer (G-Walk). Results: Maximum concentric power, peak speed, impact force, take-off force, and jump height were significantly worse in the CF group than in their healthy peers (p

Physical activity for children with chronic disease; a narrative review and practical applications

BACKGROUND

Physical activity (PA) is associated with a diverse range of health benefits. International guidelines suggest that children should be participating in a minimum of 60 min of moderate to vigorous intensity PA per day to achieve these benefits. However, current guidelines are intended for healthy children, and thus may not be applicable to children with a chronic disease. Specifically, the dose of PA and disease specific exercise considerations are not included in these guidelines, leaving such children with few, if any, evidence-based informed suggestions pertaining to PA. Thus, the purpose of this narrative review was to consider current literature in the area of exercise as medicine and provide practical applications for exercise in five prevalent pediatric chronic diseases: respiratory, congenital heart, metabolic, systemic inflammatory/autoimmune, and cancer.

METHODS

For each disease, we present the pathophysiology of exercise intolerance, summarize the pediatric exercise intervention research, and provide PA suggestions.

RESULTS

Overall, exercise intolerance is prevalent in pediatric chronic disease. PA is important and safe for most children with a chronic disease, however exercise prescription should involve the entire health care team to create an individualized program.

CONCLUSIONS

Future research, including a systematic review to create evidence-based guidelines, is needed to better understand the safety and efficacy of exercise among children with chronic disease.

Physiological correlates of pulmonary function in children with cystic fibrosis

RATIONALE

Although peak aerobic capacity (VO(2peak)) has been linked to outcome in patients with cystic fibrosis (CF), measuring is time consuming, and requires expensive equipment and expertise that is not readily available in all centers. Other fitness parameters such as peak anaerobic power, measures of power and strength may be simpler to deliver in the clinic. The relationship between these measures and established outcomes such as forced expiratory volume in one second (FEV(1)) and peak aerobic power (VO(2peak)) in CF remains unclear. Therefore we evaluated (a) aerobic fitness, (b) anaerobic fitness, and (c) upper and lower body muscle strength to determine their relationship to FEV(1) and VO(2peak) in children with CF.

METHODS

Eighty-two patients (7-18 years) with CF (40 female) from the CF clinic at The Hospital for Sick Children in Toronto performed a maximal incremental cycling test to exhaustion. Anaerobic power (W) for 10 and 30 sec cycling trials as well as vertical jump (VJ) and hand grip strength (HG) were compared to FEV(1) and VO(2peak).

RESULTS

Absolute VO(2peak) (R(2)  = 0.16, P < 0.001), anaerobic power (R(2)  = 0.21, P < 0.001), and hand grip strength (R(2)  = 0.10, P = 0.003) were significantly correlated to lung function whereas measures of explosive lower body strength (VJ) were not. Anaerobic power (R(2)  = 0.16, P = 0.001) and hand grip strength (R(2)  = 0.08, P = 0.01) were related to VO(2peak). Vertical jump was correlated with VO(2peak) (R(2)  = 0.29, P < 0.001) but not FEV(1).

CONCLUSIONS

Simple fitness tests such as hand grip strength and anaerobic cycle tests may be useful indicators of lung health and fitness.

Cycle ergometer tests in children with cystic fibrosis: reliability and feasibility

The aim of this study was to assess the reliability and feasibility of cycle ergometer tests in young children with cystic fibrosis (CF). Children with CF aged 6-11 years and with stable lung disease performed two cycle ergometry tests (intermittent sprint and continuous incremental) on two occasions 1 week apart. Reliability was assessed using repeated-measures ANOVA. Bias was considered to be significant at P < 0.05 level and a coefficient of variation (CV) below 10% was considered acceptable. Feasibility and acceptability data were also collected. Sixteen children with CF completed the study: (9M:7F), 8.7(1.8) years, FEV(1) %predicted: 88.1(17.4). Power measurements recorded during the intermittent sprint test demonstrated significant bias over days (P < 0.05) and CVs were between 10% and 15%. Peak work capacity recorded during the continuous incremental test was reliable (bias P < 0.05, CV < 10%), as was heart rate and SpO(2) recorded during both tests (bias P < 0.05, CV < 10%). No problems were experienced in administering the tests and all children completed both tests on two separate occasions. There was a mixed response to questions on acceptability of tests. This is the first study to provide information on the reliability of performance measures recorded during an intermittent sprint protocol (peak power) and a continuous incremental cycle ergometry (peak work capacity) in children with CF.

Impaired lung diffusing capacity for nitric oxide and alveolar-capillary membrane conductance results in oxygen desaturation during exercise in patients with cystic fibrosis

BACKGROUND

Exercise has been shown to be beneficial for patients with cystic fibrosis (CF), but for some CF patients there is a risk of desaturation, although the predicting factors are not conclusive or reliable. We sought to determine the relationship between the diffusion capacity of the lungs for nitric oxide and carbon monoxide (DLNO and DLCO) and the components of DLCO: alveolar-capillary membrane conductance (D(M)), and pulmonary capillary blood volume (V(C)) on peripheral oxygen saturation (SaO(2)) at rest and during exercise in CF.

METHODS

17 mild/moderate CF patients and 17 healthy subjects were recruited (age=26±7 vs. 23±8 years, ht=169±8 vs. 166±8 cm, wt=65±9 vs. 59±8 kg, BMI=23±3 vs. 22±3 kg/m(2), VO(2PEAK)=101±36 vs. 55±25%pred., FEV(1)=92±22 vs. 68±25%pred., for healthy and CF, respectively, mean±SD, VO(2PEAK) and FEV(1) p<0.001). Subjects performed incremental cycle ergometry to exhaustion with continuous monitoring of SaO(2) and measures of DLNO, DLCO, D(M) and V(C) at each stage.

RESULTS

CF patients had a lower SaO(2) at rest and peak exercise (rest=98±1 vs. 96±1%, peak=97±2 vs. 93±5%, for healthy and CF, respectively, p<0.01). At rest, DLNO, DLCO, D(M) were significantly lower in the CF group (p<0.01). The difference between groups was augmented with exercise (DLNO=117±4 vs. 73±3ml/min/mmHg; DLCO=34±8 vs. 23±8ml/min/mmHg; D(M)=50±1 vs. 34±1, p<0.001, for healthy and CF respectively). Peak SaO(2) was related to resting DLNO in CF patients (r=0.65, p=0.003).

CONCLUSIONS

These results suggest a limitation in exercise-mediated increases in membrane conductance in CF which may contribute to a drop in SaO(2) and that resting DLNO can account for a large portion of the variability in SaO(2).

Exercise training in children and adolescents with cystic fibrosis: theory into practice

Physical activity and exercise training play an important role in the clinical management of patients with cystic fibrosis (CF). Exercise training is more common and recognized as an essential part of rehabilitation programmes and overall CF care. Regular exercise training is associated with improved aerobic and anaerobic capacity, higher pulmonary function, and enhanced airway mucus clearance. Furthermore, patients with higher aerobic fitness have an improved survival. Aerobic and anaerobic training may have different effects, while the combination of both have been reported to be beneficial in CF. However, exercise training remains underutilised and not always incorporated into routine CF management. We provide an update on aerobic and anaerobic responses to exercise and general training recommendations in children and adolescents with CF. We propose that an active lifestyle and exercise training are an efficacious part of regular CF patient management.

High-intensity interval training in an adolescent with cystic fibrosis: a physiological perspective

Nutritional, musculoskeletal, and/or ventilatory status can lead to a decreased exercise capacity in children with cystic fibrosis (CF). Exercise training is already part of the usual care; however, the "optimal" intensity and volume of exercise training to improve exercise capacity is still unknown. Six weeks of high-intensity interval training (HIT) for a patient with CF with a ventilatory limitation was evaluated by a cardiopulmonary exercise test (CPET). Peak oxygen uptake and peak workload increased 19% and 16%, respectively, and there was a rise in peak ventilation from 50 L/min to 75 L/min, with an increase in both breathing depth and respiratory rate. A relative short period of HIT resulted in a significant increase in exercise capacity. In patients with CF, HIT might be an effective and efficient training regimen, especially in CF patients with a ventilatory limitation. Further research is necessary to investigate whether HIT is a better alternative than traditional aerobic training programs especially in ventilatory limited patients with CF.

Clinical exercise testing in children and adolescents with cystic fibrosis

PURPOSE

To review the most common field and laboratory exercise tests available for children and adolescents with cystic fibrosis (CF).

METHODS

Relevant studies for this review were identified by electronic search of Medline and PubMed databases between the years 1958 and 2008. The bibliographies of all accessed publications were also searched. Key descriptors were cystic fibrosis, exercise testing, aerobic fitness, children, and adolescents.

RESULTS

Five field tests were selected for presentation, including discussion of their strengths and weaknesses. Laboratory tests measuring aerobic and anaerobic responses to exercise in children with CF were also selected for presentation and discussed along with a summary of safety considerations for exercise testing of children with CF.

CONCLUSION

Exercise testing is regarded an important prognostic tool in CF care. However, despite its beneficial effects, clinical exercise testing seems underused. Clinicians and their staff should encourage patients with CF to be physically active and recommend exercise testing annually.

Asma induzida pelo exercício: aspectos atuais e recomendações

OBJETIVO: Descrever os mecanismos da asma induzida pelo exercício (AIE), bem como os efeitos de diferentes tipos de treinamento físico na função pulmonar e nas capacidades aeróbia e anaeróbia. Destaca-se a importância de um diagnóstico correto mediante o teste de exercício e, no manejo, o uso de drogas beta-adrenérgicas e anticolinérgicas. FONTE DOS DADOS: Os artigos foram criteriosamente escolhidos utilizando as bases de dados PubMed e Scielo pelo ano de publicação e dando preferência a ensaios clínicos randomizados, com critérios de seleção da amostra bem definidos. SÍNTESE DOS DADOS: Os mecanismos para explicar a AIE permanecem sem conclusão, mas parece haver uma interação fisiológica entre as hipóteses aqui apresentadas. O uso de medicamentos e as freqüentes crises durante o exercício aparecem como fatores limitantes para a prática de exercícios físicos, conduzindo para um estilo de vida sedentário. CONCLUSÃO: Deve-se incentivar a prática de exercícios devidamente prescritos e minimizar as restrições aos sujeitos com AIE.

Effects of Anaerobic Training in Children With Cystic Fibrosis

BACKGROUND

Children's physical activity patterns are characterized by short-term anaerobic activities. Anaerobic exercise performance in children with cystic fibrosis (CF) has received little attention compared to aerobic performance. This study investigated the effects of anaerobic training in children with CF.

DESIGN AND METHODS

Twenty patients were randomly assigned to the training group (TG) [11 patients; mean (+/- SD) age, 13.6 +/- 1.3 years; mean FEV(1), 75.2 +/- 20.7% predicted] or the control group (CG) [9 patients; mean age, 14.2 +/- 2.1 years; FEV(1), 82.1 +/- 19.1% predicted]. The TG trained 2 days per week for 12 weeks, with each session lasting 30 to 45 min. The training program consisted of anaerobic activities lasting 20 to 30 s. The control subjects were asked not to change their normal daily activities. Body composition, pulmonary function, peripheral muscle force, habitual physical activity, aerobic and anaerobic exercise performance, and quality of life were reevaluated at the end of the training program, and again after a 12-week follow-up period.

RESULTS

Patients in the TG significantly improved their anaerobic performance, aerobic performance, and quality of life. No significant changes were seen in other parameters, and no improvements were found in CG. After the follow-up period, only anaerobic performance and quality of life in TG were significantly higher compared to pretraining values.

CONCLUSIONS

Anaerobic training has measurable effects on aerobic performance (although not sustained), anaerobic performance, and health-related quality of life in children with CF. Therefore, anaerobic training could be an important component of therapeutic programs for CF patients.

Growth hormone and exercise tolerance in patients with cystic fibrosis

Cystic fibrosis (CF) is a life-limiting inherited disorder characterised by pulmonary disease, pancreatic dysfunction and symptoms of malnutrition that are all interrelated with low exercise capacity and poor survival rate. Therapy with growth hormone (GH) may improve the reduced dimensional and functional capacity associated with poor nutritional status and catabolism and therefore improve exercise tolerance, quality of life and survival rate in patients with CF. The literature about GH treatment and its effect on exercise tolerance are rather limited, not always consistent and methodological concerns restrict further analysis. GH treatment may have beneficial effects on both growth and exercise tolerance without serious complications in prepubertal children with CF. The observed dimensional changes of the muscular, cardiovascular and pulmonary system seem to improve aerobic exercise capacity and respiratory and peripheral muscle strength. The physiological background of the observed changes is not yet fully understood, therefore, larger-scale studies with an optimised design are required.

Anaerobic exercise in pediatric cystic fibrosis

Anaerobic fitness is important for daily functioning of children with cystic fibrosis (CF). The aim of this study was to assess the determinants of anaerobic performance in CF. Anaerobic performance was measured in 39 children with CF (mean age, 13.2 +/- 1.8 (SD) years, forced expired volume in 1 sec (FEV(1)) 81.6 +/- 22.1% predicted), using a Wingate anaerobic test. Significant associations were found for peak power (PP) and mean power (MP) with fat-free mass (FFM) body weight, body mass index, maximal isometric muscle force, and aerobic capacity. Pulmonary function was correlated with anaerobic indices when controlled for FFM. Multiple regression analysis indicated that FFM and FEV(1) accounted for 82% and 86% of the variability in PP and MP, respectively. Patients with moderate CF (FEV(1) < 80%), as compared to mild CF (FEV(1) >/= 80%), had higher PP (difference = 85 W, 95% CI = 27-144 W) and MP (difference = 53 W, 95% CI = 42-63 W) at equivalent FFM. Our results indicate that FFM and pulmonary function are important determinants of anaerobic exercise performance in children with CF. With progression of pulmonary disease, anaerobic performance may be enhanced.

Training of aerobic and anaerobic fitness in children with asthma

OBJECTIVE

To assess the effect of a training protocol on aerobic and anaerobic fitness in children with asthma.

STUDY DESIGN

Sixteen boys (mean age: 13 years; range: 10-16 years) with mild-to-moderate asthma participated in a rehabilitation program that included 6 weeks of individualized training on a cycle ergometer. Two groups were randomly formed: the control group (CG, n = 7) and the training group (TG, n = 9), which exercised at an intensity set at the heart rate corresponding to the ventilatory threshold, with 1-minute sprints against the maximal aerobic power (MAP) every 4 minutes. Session duration was 45 minutes, 3 sessions per week. Changes in maximal oxygen uptake (VO(2)max), MAP, short-term peak power (PP), and pulmonary function were assessed.

RESULTS

Two patients of the training group did not complete the study. Pulmonary function remained unchanged in both groups. Improvement in both aerobic and anaerobic fitness was significant only in the training group (TG vs CG): VO(2)max +18% +/- 2.1% versus +9% +/- 4.5% (P <.05), MAP +32% +/- 5% versus 12% +/- 7% (P <.05), PP +21% +/- 5.7% versus +8.8% +/- 10% (P <.01).

CONCLUSION

Exercise training with high-intensity bouts is well tolerated in children with mild-to-moderate asthma. When included in a global rehabilitation program, this type of training improves both aerobic and anaerobic fitness. Anaerobic activities should be considered in sports rehabilitation programs for children with asthma.