Physical activity in relation to motor performance, exercise capacity, sports participation, parental perceptions, and overprotection in school aged children with a critical congenital heart defect.

OBJECTIVE: To depict objectively measured moderate-to-vigorous physical activity (MVPA), motor performance (MP), cardiorespiratory fitness (CRF), organized sports participation, parental perceptions of vulnerability and parenting style in children with a Critical Congenital Heart Disease (CCHD), and to explore whether these factors are associated with MVPA. STUDY DESIGN: A prospective observational cohort study in 62 7-10 years old children with a CCHD. RESULTS: On average, children with CCHD spent 64 min on MVPA per day (accelerometry), 61 % met the international WHO physical activity guideline. Only 12 % had >60 min of MVPA daily. Eighteen percent had a motor delay (movement-assessment-battery-for children-II) and 38 % showed a below average CRF (cardiopulmonary exercise test using the Godfrey ramp protocol). Seventy-seven percent participated in organized sports activities at least once a week. Twenty-one percent of the parents are classified as overprotective (parent protection scale) and 7.3 % consider their child as being vulnerable (child vulnerability scale). A significant positive association was found between MVPA and MP (rs = 0.359), CRF(V̇O2peak/ml/kg: rs = 0.472 and Wpeak/kg: rs = 0.396) and sports participation (rs = 0.286). Children who were perceived as vulnerable by their parents showed a significantly lower MVPA (rs = -0.302). No significant associations were found between mean MVPA and parental overprotection. CONCLUSION: Even though the majority of school aged children with a CCHD is sufficiently active, counseling parents regarding the importance of sufficient MVPA and sports participation, especially in parents who consider their child being vulnerable, could be useful. Since motor delays can be detected at an early age, motor development could be an important target to improve exercise capacity and sports participation to prevent inactivity in children with a CCHD.

Is Measuring Physical Literacy in School-Aged Children With Cystic Fibrosis or Congenital Heart Disease Needed?

PURPOSE: To explore the association between cardiorespiratory fitness and other physical literacy domains in children with cystic fibrosis (CF) or congenital heart disease (CHD). METHODS: In 28 children with CF (n = 10) or CHD (n = 18), aged 7 to 11 years, cardiorespiratory fitness and the following physical literacy domains were measured: ( a ) physical competence, ( b ) motivation and confidence, ( c ) knowledge and understanding, and ( d ) daily behavior (ie, self-perceived moderate-to-vigorous physical activity [MVPA]). RESULTS: Cardiorespiratory fitness was significantly associated with motivation and confidence and self-perceived MVPA. There were no other significant associations. CONCLUSIONS: Cardiorespiratory fitness is associated with self-perceived MVPA, motivation, and confidence in children with CF or CHD.

Early Determinants of Adverse Motor Outcomes in Preschool Children with a Critical Congenital Heart Defect.

Neurodevelopmental disabilities are common in infants with critical congenital heart disease (CCHD). A prospective, longitudinal cohort study was conducted to establish the prevalence and early determinants of adverse motor outcomes in infants who underwent cardiac surgery with cardiopulmonary bypass before six months of age. Motor development was assessed in 147 preschoolers using the Movement Assessment Battery for children-II. Although the majority displayed an average motor development, 22% of preschool children with CCHD deteriorated in their motor developmental score compared to their previous assessment at 18 months, especially in those with an aortic arch anomaly (AAA) (35%). Individual stability over time appeared to be moderate and the number of children with a motor delay increased, up to 20% in children with AAA. Motor development up to 42 months was best predicted by gestational age, cardio pulmonary bypass time, aortic cross clamp time, number of heart catheterizations up to 18 months and early motor outcomes. The increase in number of preschool children with a motor delay underlines the importance of longitudinal screening of motor skills in children with CCHD at risk for adverse motor outcomes. Offering early interventions may protect their current and future cardiovascular health as motor development is an independent predictor of exercise capacity, physical activity and participation in daily living.

Longitudinal Motor-Developmental Outcomes in Infants with a Critical Congenital Heart Defect.

Infants with critical congenital heart defects (CCHDs) are at increased risk for neurodevelopmental delays. The early identification of motor delays is clinically relevant to prevent or reduce long-term consequences. The current study aims to describe the motor-developmental pathways of infants with a CCHD. Motor development was assessed in 215 infants and toddlers using the Dutch version of the Bayley-III. At 3 months (n = 165), 9 months (n = 188), and 18 months (n = 171) the motor composite scores were 97, 98, and 104, respectively. A motor composite score of ≤-2 SD was only seen in 2.4%, 0%, and 2.3%, respectively, with gross motor deficits being observed more often than fine motor deficits (12% vs. 0% at 18 months). Over 90% of infants who scored average at 9 months still did so at 18 months. The majority of infants with below-average gross motor scores (≤-1) at 9 months still had a below-average or delayed motor score (≤-2 SD) at 18 months. Abnormal gross motor scores (≤-2 SD) increased with age. Infants with single-ventricle physiology performed significantly (p ≤ 0.05) worse on both fine and gross motor skills at 9 and 18 months compared to infants with other CCHDs.

Motor Developmental Delay After Cardiac Surgery in Children With a Critical Congenital Heart Defect: A Systematic Literature Review and Meta-analysis.

PURPOSE: To systematically review evidence regarding the severity and prevalence of motor development in children with a critical congenital heart defect (CCHD) without underlying genetic anomalies. SUMMARY OF KEY POINTS: Twelve percent of all included studies reported abnormal mean motor developmental scores, and 38% reported below average motor scores. Children with single-ventricle physiology, especially those with hypoplastic left heart syndrome, had the highest severity and prevalence of motor delay, particularly at 0 to 12 months. Most included studies did not differentiate between gross and fine motor development, yet gross motor development was more affected. RECOMMENDATIONS FOR CLINICAL PRACTICE: We recommend clinicians differentiate between the type of heart defect, fine and gross motor development, and the presence of genetic anomalies. Furthermore, increased knowledge about severity and prevalence will enable clinicians to tailor their interventions to prevent motor development delays in CCHD.

Severe Fatigue Is Common Among Pediatric Patients with Primary Immunodeficiency and Is Not Related to Disease Activity.

PURPOSE: Fatigue is a distressing symptom commonly reported among pediatric patients with primary immunodeficiency (PID). However, the relationship between fatigue and disease activity is currently unknown. METHODS: In this cross-sectional study, we examined the prevalence of severe fatigue, the effect of fatigue on health-related quality of life (HRQoL), and the effects of disease activity and comorbidity on fatigue severity among pediatric patients 2-18 years of age with PID. Fatigue and HRQoL were assessed using the pediatric quality of life inventory multidimensional fatigue scale (PedsQL MFS) and generic core scales (PedsQL GCS), respectively. Linear regression analyses and an analysis of covariance were used to compare the fatigue scores with the scores obtained from a healthy control group. Data were adjusted for age and sex. RESULTS: Of the 91 eligible patients, 79 were assessed (87% participation rate), with a mean age of 10.4 ± 4.4 years. Pediatric patients with PID reported significantly higher fatigue levels compared to healthy peers, with an 18.9% prevalence of severe fatigue. Moreover, higher fatigue levels were inversely associated with HRQoL in all domains and directly associated with school absences. We found that severe fatigue was comparable between common variable immunodeficiency (CVID), combined immunodeficiency (CID), and selective immunoglobulin A deficiency (SIgAD) patients, but was not reported in the X-linked agammaglobulinemia (XLA) patients studied. Finally, fatigue severity was not significantly associated with disease activity or comorbidity. CONCLUSIONS: Nearly 20% of pediatric patients with PID reported experiencing severe fatigue, and fatigue was reported among a wide range of PID subcategories. In addition, severe fatigue negatively affected the patient's quality of life and daily functioning, but was not associated with disease activity or comorbidity. Thus, targeting severe fatigue might be a promising strategy for improving the overall well-being and quality of life of pediatric patients with PID.

Motor function impairment is an early sign of CLN3 disease.

OBJECTIVE: To delineate timing of motor decline in CLN3 disease. METHODS: Motor function, assessed by the 6-Minute Walk Test (6MWT), was evaluated repeatedly in 15 patients with CLN3 disease, resulting in 65 test results and during one occasion in 2 control cohorts. One control cohort (n = 14) had isolated visual impairment; a second cohort (n = 12) exhibited visual impairment in combination with neurologic impairments. Based on 6MWT reference values in healthy sighted children, z scores of 6MWT results in patients with CLN3 disease and control cohort individuals were calculated. 6MWT results were correlated with age-including multilevel modeling analysis allowing assessment of imbalanced repeated measurements-and with Unified Batten Disease Rating Scale (UBDRS) scores. RESULTS: In CLN3 disease, 6MWT scores were already impaired from first testing near diagnosis (mean z scores of -3.6 and -4.7 at 7 and 8 years of age, respectively). Afterwards, 6MWT scores continuously declined with age (r = -0.64, p < 0.0001) and with increasing UBDRS scores (r = -0.60, p = 0.0001), confirming correlation with disease progression. The decrease was more pronounced at a later age, as shown by the nonlinear multilevel model for 6MWT results in CLN3 disease (y = 409.18 - [0.52 × age2]). In contrast, an upward trend of 6MWT scores with age was observed in the control cohort with isolated visual impairment (r = 0.56; p = 0.04) similar to healthy, sighted children. The control cohort with additional neurologic impairments displayed a slightly decreased 6MWT walking distance independent of age. CONCLUSIONS: The 6MWT unveils early onset of motor decline in CLN3 disease.

A Systematic Approach to Interpreting the Cardiopulmonary Exercise Test in Pediatrics.

The use of cardiopulmonary exercise testing in pediatrics provides critical insights into potential physiological causes of unexplained exercise-related complaints or symptoms, as well as specific pathophysiological patterns based on physiological responses or abnormalities. Clinical interpretation of the results of a cardiopulmonary exercise test in pediatrics requires specific knowledge with regard to pathophysiological responses and interpretative strategies that can be adapted to address concerns specific to the child's medical condition or disability. In this review, the authors outline the 7-step interpretative approach that they apply in their outpatient clinic for diagnostic, prognostic, and evaluative purposes. This approach allows the pediatric clinician to interpret cardiopulmonary exercise testing results in a systematic order to support their physiological reasoning and clinical decision making.

Validation of the Modified Shuttle Test to Predict Peak Oxygen Uptake in Youth Asthma Patients Under Regular Treatment.

Background: Oxygen uptake (VO2) evaluations by cardiopulmonary exercise test is expensive and time-consuming. Estimating VO2 based on a field test would be an alternative. Objective: To develop and validate an equation to predict VO2peak based on the modified shuttle test (MST). Methods: Cross sectional study, with 97 children and adolescents with asthma. Participants were divided in two groups: the equation group (EG), to construct the equation model of VO2peak, and the cross-validation group (VG). Each subject performed the MST twice using a portable gas analyzer. The peak VO2peak during MST was used in the equation model. The patients' height, weight, gender, and distance walked (DW) during MST were tested as independent variables. Results: The final model [-0.457 + (gender × 0.139) + (weight × 0.025) + (DW × 0.002)] explained 87% of VO2peak variation. The VO2peak predicted was similar to VO2peak measured by gas analyzer (1.9 ± 0.5 L/min and 2.0 ± 0.5 L/min, respectively) (p = 0.67), and presented significant ICC 0.91 (IC95% 0.77 to 0.96); p < 0.001. The Bland-Altman analysis showed low bias (-0.15 L/min) and limits of agreement (-0.65 to 0.35 L/min). There was no difference in DW between EG (760 ± 209 m) and VG (731 ± 180 m), p = 0.51. Conclusion: The developed equation adequately predicts VO2peak in pediatric patients with asthma.

Physical activity and sedentary behavior following pediatric burns - a preliminary investigation using objective activity monitoring.

BACKGROUND: Adequate levels of regular physical activity (PA) are crucial for health and well-being. Pediatric burn injuries can have major physiological consequences in both the short and long term. The question is whether these consequences affect post burn PA levels. This study therefore aimed to describe PA and sedentary behavior (SB) in children and adolescents 1-5 years after burn injury. METHODS: Daily PA and SB were monitored in 20 children and adolescents (12 boys and 8 girls, aged 6-17 years, with burns covering 10-37% of total body surface area, 1-5 years post burn) for 1 week using the ActiGraph GTX3+ accelerometer. Activity counts were categorized into SB, light PA, moderate PA, vigorous PA, moderate-to-vigorous PA (MVPA), and total PA. Outcomes were compared with non-burned reference values and PA levels recommended by the World Health Organization (WHO). RESULTS: The participants spent about 5.1 h per day on total PA and 7.4 h on SB. Most of the active time (~ 83%) was categorized as light PA. Thirty-five percent of the group, especially the young boys, spent on average ≥ 60 min on MVPA per day. The boys, although with large interindividual differences, spent more time on MVPA than the girls (p < .005). Older age was associated with less PA time, while more time was spent sedentary. No trends were found indicating an effect of burn characteristics, time post burn, or length of hospital stay, and no differences were found with non-burned peers. CONCLUSION: Duration and intensity of PA and SB in children and adolescents 1-5 years after burn injury were similar to non-burned peers. However, only 35% of the group met the WHO physical activity recommendation. Given the increased long term risk for physical conditions following pediatric burns, physical activity should be encouraged in this vulnerable population. TRIAL REGISTRATION: The study is registered in the National Academic Research and Collaborations Information System of the Netherlands (OND1348800).

Trajectories of cardiorespiratory fitness in patients with juvenile dermatomyositis.

Objectives: Previous research demonstrated decreased cardiorespiratory fitness (CRF) in patients with JDM during active disease and remission. However, longitudinal data regarding trajectories of CRF are currently lacking. The objective of this study was to determine trajectories of CRF in patients with both monocyclic and chronic JDM, and to identify potential predictors of these trajectories. Methods: Thirty-six patients with JDM [median age (interquartile range) at diagnosis: 8.3 (6.3-15.4) years] treated in our paediatric rheumatology outpatient clinic were included. All patients performed multiple cardiopulmonary exercise tests between 2003 and 2016. Relevant CRF parameters were analysed, including peak oxygen uptake, maximal workload, mechanical efficacy and oxygen uptake at ventilatory anaerobic threshold. We analysed trajectories up to 10 years after diagnosis and determined predictors of CRF outcome parameters by multilevel analyses. Results: Trajectories demonstrated significant declines in CRF during the active phase of the disease with subsequent improvement in CRF during the initial years after diagnosis. However, hereafter no further improvements, and even a decrease, in CRF were observed over time in both monocyclic and chronic subtypes of JDM. We found that a longer disease duration, younger age of onset and higher prednisone dose negatively influence CRF. Conclusion: Patients with both monocyclic and chronic JDM show decreases in long-term CRF trajectories. Longer disease duration, younger age of onset and higher prednisone dose negatively influence CRF. This study stresses the need for regular evaluation of CRF and implementation of (exercise) interventions to improve CRF in patients with JDM, even in monocyclic patients.

Perceived fatigue following pediatric burns.

PURPOSE: Fatigue is a common consequence of numerous pediatric health conditions. In adult burn survivors, fatigue was found to be a major problem. The current cross-sectional study is aimed at determining the levels of perceived fatigue in pediatric burn survivors. METHODS: Perceived fatigue was assessed in 23 children and adolescents (15 boys and 8 girls, aged 6-18 years, with burns covering 10-46% of the total body surface area, 1-5 years post burn) using both child self- and parent proxy reports of the Pediatric Quality of Life Inventory Multidimensional Fatigue Scale. Outcomes were compared with reference values of non-burned peers. RESULTS: At group level, pediatric burn survivors did not report significantly more symptoms of fatigue than their non-burned peers. Individual assessments showed, however, that four children experienced substantial symptoms of fatigue according to the child self-reports, compared to ten children according to the parent proxy reports. Furthermore, parents reported significantly more symptoms of fatigue than the children themselves. Age, gender, extent of burn, length of hospital stay, and number of surgeries could not predict the level of perceived fatigue post-burn. CONCLUSIONS: Our results suggest that fatigue is prevalent in at least part of the pediatric burn population after 1-5 years. However, the fact that parents reported significantly more symptoms of fatigue then the children themselves, hampers evident conclusions. It is essential for clinicians and therapists to consider both perspectives when evaluating pediatric fatigue after burn and to determine who needs special attention, the pediatric burn patient or its parent.

Cardiopulmonary Exercise Testing in Pediatrics.

Aerobic fitness is an important determinant of overall health. Higher aerobic fitness has been associated with many health benefits. Because myocardial ischemia is rare in children, indications for exercise testing differ in children compared with adults. Pediatric exercise testing is imperative to unravel the physiological mechanisms of reduced aerobic fitness and to evaluate intervention effects in children and adolescents with a chronic disease or disability. Cardiopulmonary exercise testing includes the measurement of respiratory gas exchange and is the gold standard for determining aerobic fitness, as well as for examining the integrated physiological responses to exercise in pediatric medicine. As the physiological responses to exercise change during growth and development, appropriate pediatric reference values are essential for an adequate interpretation of the cardiopulmonary exercise test.

Consensus-based recommendations for the management of juvenile dermatomyositis.

BACKGROUND: In 2012, a European initiative called Single Hub and Access point for pediatric Rheumatology in Europe (SHARE) was launched to optimise and disseminate diagnostic and management regimens in Europe for children and young adults with rheumatic diseases. Juvenile dermatomyositis (JDM) is a rare disease within the group of paediatric rheumatic diseases (PRDs) and can lead to significant morbidity. Evidence-based guidelines are sparse and management is mostly based on physicians' experience. Consequently, treatment regimens differ throughout Europe. OBJECTIVES: To provide recommendations for diagnosis and treatment of JDM. METHODS: Recommendations were developed by an evidence-informed consensus process using the European League Against Rheumatism standard operating procedures. A committee was constituted, consisting of 19 experienced paediatric rheumatologists and 2 experts in paediatric exercise physiology and physical therapy, mainly from Europe. Recommendations derived from a validated systematic literature review were evaluated by an online survey and subsequently discussed at two consensus meetings using nominal group technique. Recommendations were accepted if >80% agreement was reached. RESULTS: In total, 7 overarching principles, 33 recommendations on diagnosis and 19 recommendations on therapy were accepted with >80% agreement among experts. Topics covered include assessment of skin, muscle and major organ involvement and suggested treatment pathways. CONCLUSIONS: The SHARE initiative aims to identify best practices for treatment of patients suffering from PRD. Within this remit, recommendations for the diagnosis and treatment of JDM have been formulated by an evidence-informed consensus process to produce a standard of care for patients with JDM throughout Europe.

Internet Program for Physical Activity and Exercise Capacity in Children With Juvenile Idiopathic Arthritis: A Multicenter Randomized Controlled Trial.

OBJECTIVE: To determine the effects of Rheumates@Work, an internet-based program supplemented with 4 group sessions, aimed at improving physical activity, exercise capacity, health-related quality of life (HRQoL), and participation in children with juvenile idiopathic arthritis. METHODS: Patients were recruited from 3 pediatric rheumatology centers in The Netherlands for an observer-blinded, randomized controlled multicenter trial. Physical activity level, time spent in rest, light, and moderate-to-vigorous physical activity (MVPA) were recorded in a diary and with an accelerometer, before intervention, after intervention, and at followup after 3 and 12 months (intervention group only). Exercise capacity was assessed using the Bruce treadmill protocol, HRQoL was assessed with the Pediatric Quality of Life Inventory generic core scale, and participation in school and in physical education classes were assessed by questionnaire. RESULTS: The intervention group consisted of 28 children, and there were 21 children in the control group. MVPA, exercise capacity, and participating in school and physical education classes improved significantly in the intervention group. HRQoL improved in the control group. No significant differences were found between groups. The effect of Rheumates@Work on physical activity and exercise capacity lasted during the 12 months of followup. Improvements in physical activity were significantly better for the cohort starting in winter compared to the summer cohort. CONCLUSION: Rheumates@Work had a positive, albeit small, effect on physical activity, exercise capacity, and participation in school and physical education class in the intervention group. Improvements lasted for 12 months. Participants who started in winter showed the most improvement. Rheumates@Work had no effect on HRQoL.

Do activity monitors increase physical activity in adults with overweight or obesity? A systematic review and meta-analysis.

OBJECTIVE: To systematically assess contemporary knowledge regarding behavioral physical activity interventions including an activity monitor (BPAI+) in adults with overweight or obesity. METHODS: PubMed/MEDLINE, Embase, CINAHL, PsycINFO, CENTRAL, and PEDro were searched for eligible full-text articles up to 1 July 2015. Studies eligible for inclusion were (randomized) controlled trials describing physical activity outcomes in adults with overweight or obesity. Methodological quality was independently assessed employing the Cochrane Collaboration's tool for risk of bias. RESULTS: Fourteen studies (1,157 participants) were included for systematic review and 11 for meta-analysis. A positive trend in BPAI+ effects on several measures of physical activity was ascertained compared with both wait list or usual care and behavioral physical activity interventions without an activity monitor (BPAI-). No convincing evidence of BPAI+ effectiveness on weight loss was found compared with BPAI-. CONCLUSIONS: Behavioral physical activity interventions with an activity monitor increase physical activity in adults with overweight or obesity. Also, adding an activity monitor to behavioral physical activity interventions appears to increase the effect on physical activity, although current evidence has not yet provided conclusive evidence for its effectiveness.

Muscles in motion: a randomized controlled trial on the feasibility, safety and efficacy of an exercise training programme in children and adolescents with juvenile dermatomyositis.

OBJECTIVE: To study for the first time in a randomized controlled trial the feasibility, safety and efficacy of an exercise training programme in children and adolescents with JDM. METHODS: Patients were randomly assigned to the Intervention Group (IG; n = 14) or Waiting Control Group (WCG; n = 12). The intervention comprised an individually tailored 12-week home-based exercise programme of treadmill interval training and strength exercises. The efficacy of the IG over usual care (WCG) was examined with mixed linear regression (intention-to-treat). Effect sustainability during 12 weeks follow-up was also examined. RESULTS: Seventy-five percent of the participants completed the intervention. Reasons for discontinuation were motivation/fatigue, recurrent infections and increasing physical complaints. No hospitalizations occurred and immune suppressive therapy remained stable or decreased in the patients who participated in the intervention. The estimated marginal means after the intervention period were significantly in favour of the IG compared with the WCG for standing long jump distance [difference between groups (95% CI): 13 cm (2-23)], the 30-s number of push-ups [8 (3-13)] and sit-ups [4 (0.4-8)], and the parent Childhood Health Assessment Questionnaire 30 + 8 score [-0.13 (-0.24 to - 0.01)] and effects sustained at follow-up. A trend was seen for the maximal oxygen uptake divided by body mass during maximal exercise treadmill testing; the IG scored 3.0 ml/kg/min (-1.3 to 7.3) higher compared with the WCG. Other outcomes (e.g. isometric muscle strength and perception of fatigue) did not differ between IG and WCG. CONCLUSION: Exercise training is of value in the clinical management of JDM.

Brief Report: Association of Myositis Autoantibodies, Clinical Features, and Environmental Exposures at Illness Onset With Disease Course in Juvenile Myositis.

OBJECTIVE: To identify early factors associated with disease course in patients with juvenile idiopathic inflammatory myopathies (IIMs). METHODS: Univariable and multivariable multinomial logistic regression analyses were performed in a large juvenile IIM registry (n = 365) and included demographic characteristics, early clinical features, serum muscle enzyme levels, myositis autoantibodies, environmental exposures, and immunogenetic polymorphisms. RESULTS: Multivariable associations with chronic or polycyclic courses compared to a monocyclic course included myositis-specific autoantibodies (multinomial odds ratio [OR] 4.2 and 2.8, respectively), myositis-associated autoantibodies (multinomial OR 4.8 and 3.5), and a documented infection within 6 months of illness onset (multinomial OR 2.5 and 4.7). A higher overall clinical symptom score at diagnosis was associated with chronic or monocyclic courses compared to a polycyclic course. Furthermore, severe illness onset was associated with a chronic course compared to monocyclic or polycyclic courses (multinomial OR 2.1 and 2.6, respectively), while anti-p155/140 autoantibodies were associated with chronic or polycyclic courses compared to a monocyclic course (multinomial OR 3.9 and 2.3, respectively). Additional univariable associations of a chronic course compared to a monocyclic course included photosensitivity, V-sign or shawl sign rashes, and cuticular overgrowth (OR 2.2-3.2). The mean ultraviolet index and highest ultraviolet index in the month before diagnosis were associated with a chronic course compared to a polycyclic course in boys (OR 1.5 and 1.3), while residing in the Northwest was less frequently associated with a chronic course (OR 0.2). CONCLUSION: Our findings indicate that myositis autoantibodies, in particular anti-p155/140, and a number of early clinical features and environmental exposures are associated with a chronic course in patients with juvenile IIM. These findings suggest that early factors, which are associated with poorer outcomes in juvenile IIM, can be identified.

Response profiles of oxygen uptake efficiency during exercise in healthy children.

BACKGROUND: Oxygen uptake efficiency (OUE), the relation between oxygen uptake (VO2) and minute ventilation (VE), differs between healthy children and children with heart disease. This study aimed to investigate the normal response profiles of OUE during a progressive cardiopulmonary exercise test. DESIGN: Cross-sectional. METHODS: Healthy children between eight and 19 years of age (114 boys and 100 girls, mean ± SD age 12.7 ± 2.8 years) performed a maximal cardiopulmonary exercise test. Peak VO2 (VO2peak), ventilatory threshold and peak VE were determined. OUE was determined by the OUE plateau (OUEP), OUE at the ventilatory threshold (OUE@VT) and OUE slope (OUES). RESULTS: OUEP (42.4 ± 4.6) and OUE@VT (41.9 ± 4.7) were similar and less variable than OUES (2138 ± 703). OUEP correlated strongly with OUE@VT (r = 0.974); however, OUEP was weak-to-moderately correlated with VO2peak (r = 0.646), the ventilatory threshold (r = 0.548) and OUES (r = 0.589). OUES correlated strongly with VO2peak (r = 0.948) and the ventilatory threshold (r = 0.856). Reference centiles for OUEP show an almost linear increase from about 37 in eight-year olds to about 47 in 18-year olds, with no sex-difference. OUES increased from about 1400 in eight-year-old boys to approximately 3500 in 18-year-old boys. OUES increased from roughly 1250 in eight-year-old girls to about 2650 in 18-year-old girls. CONCLUSIONS: This study provides sex- and age-related normative values for both OUEP and OUES, which facilitates the interpretation of OUE in children. OUEP and OUES are objective and non-invasive cardiopulmonary exercise test parameters which do not require a maximal effort and might be indicative of cardiorespiratory function during exercise.