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Background: Carbon dioxide (CO2) retention during exercise is uncommon in mild to moderate lung disease in cystic fibrosis (CF). The ability to deal with increased CO2 is dependent on the degree of airflow limitation and inherent CO2 sensitivity. CO2 retention (CO2R) can be defined as a rise in PETCO2 tension of ⩾5 mm Hg with exercise together with a failure to reduce PETCO2 tension after peak work by at least 3 mm Hg by the termination of exercise. Aim: To ascertain if carbon dioxide retention during exercise is associated with more rapid decline in lung function. Methods: Annual spirometric and exercise data from 58 children aged 11-15 years, with moderate CF lung disease between 1996 and 2002 were analysed. Results: The mean FEV1 at baseline for the two groups was similar; the CO2R group (n =15) was 62% and the non-CO2 retention group (CO2NR) was 64% (n = 43). The decline in FEV1 after 12 months was -3.2% (SD 1.1) in the CO2R group and -2.3% (SD 0.9) in the CO2NR group. The decline after 24 months was -6.3% (SD 1.3) and -1.8% (SD 1.1) respectively. After 36 months, the decline in FEV1 was -5.3% (SD 1.2) and -2.6% (SD 1.1) respectively. The overall decline in lung function was 14.8% (SD 2.1) in the CO2R group and 6.7% (SD 1.8) in the CO2NR group. Using the primary outcome measure as a decline in FEV1 of >9%, final multivariate analysis showed that the relative risks for this model were (95% CIs in parentheses): ΔPETCO2 11.61 (3.41 to 24.12), peak VO2 1.23 (1.10 to 1.43), and initial FEV1 1.14(1.02 to 1.28). Conclusion: Results show that the inability to defend carbon dioxide during exercise is associated with a more rapid decline in lung function. [ABSTRACT FROM AUTHOR]

Children with arthritis face challenges when they try to increase their physical activity. The study's objective was to identify elements of a successful community-based exercise program for children with arthritis by investigating the perspectives of fitness instructors who led the program. This qualitative study used a phenomenological approach. Four fitness instructors participated in individual interviews. Themes were developed through inductive analytic methods. Three main themes were identified: (a) children with arthritis require encouragement and guidance throughout the program from fitness instructors who understand their arthritis, and support from parents and peers; (b) children need help to overcome their negative perceptions about exercise; and (c) exercise program participation can launch the adoption of a more active lifestyle. Pediatric physiotherapists can encourage the establishment of successful exercise programs for children with arthritis in nonmedical or community environments through the formation of supportive, education-based partnerships with community-based fitness instructors.

Purpose: To understand potential benefits of exercise in the cystic fibrosis (CF) population, there needs to be accurate methods to quantify it. The Habitual Activity Estimation Scale (HAES) questionnaire has been shown to be a feasible tool to measure physical activity however the reliability and validity have yet to be determined in the CF population., Methods: Fourteen (seven male, seven female) patients aged 16.2 +/- 4.2 years with CF participated in this study. Participants were clinically stable at the time of the study and participating in their habitual physical activity. To assess reliability, patients completed the HAES and a validated 3-day activity diary, and wore an ActiGraph Accelerometer for two consecutive weeks. Validity was assessed by comparing the activity results of each of the three instruments over a single week time period., Results: ICC estimates of reliability for the HAES, diary, and accelerometer were 0.72 (P < 0.0001), 0.76 (P < 0.0001), 0.63 (P < 0.0001), respectively. Validity analysis indicated that there were significant relationships between the participants' activity results as estimated by the HAES, diary and accelerometer. Further, significant relationships were detected between activity measures when broken into morning, afternoon, or evening periods, and between measures from weekday or weekend days. There were also significant relationships among the three instruments when recording different activity levels (somewhat inactive, somewhat active, and very active)., Conclusion: The findings of this study suggest that the HAES questionnaire is a reliable and valid instrument that can be used to assess activities of varying intensity in patients with CF.

Our objective was to study exercise capacity and cardiorespiratory response to exertion in survivors of congenital diaphragmatic hernia (CDH). This was a cross-sectional cohort study of 23 CDH survivors, aged 10-16 years, and 23 gender- and age-matched controls. Exercise testing was performed on a cycle ergometer, with cardiac output measurements made using exponential CO2 rebreathing. Pretest cardiorespiratory assessment was done by echocardiography and pulmonary function testing. Statistical analysis was performed using Student's t-test, regression analysis, and longitudinal model computing with spatial covariance structure. No echocardiographic evidence for pulmonary hypertension was found at rest (right ventricular systolic pressures, 27 +/- 6 mmHg). Mean pulmonary artery diameter on the side of the CDH was significantly smaller than contralaterally, but was within normal range (z-score, 0 +/- 1.1 vs. 1.2 +/- 1.6, P < 0.01). Exercise capacity was mildly reduced in CDH compared to controls and predictive data (maximum workload, 77% +/- 12% vs. 91% +/- 16% of predicted, P < 0.01). Cardiorespiratory response to exertion was not significantly different between groups. In conclusion, most adolescent CDH survivors have nearly normal exercise capacity and cardiorespiratory response to exertion. This study may prove useful in comparisons with future cohorts comprising more severely affected individuals now surviving due to improved neonatal care., (Copyright 2006 Wiley-Liss, Inc.)

Objective: The purpose of this study was to determine the fetal response to submaximal maternal exercise at 22 to 26 weeks in pregnancies with abnormal uterine artery Doppler., Study Design: This was a prospective comparison of singleton pregnancies with uteroplacental vascular insufficiency (UPVI) (mean uterine pulsatility index [PI] values >1.45 [n = 12]) and those with normal uterine artery Doppler (n = 23). Maternal and fetal cardiovascular responses to 5 minutes of steady state cycling at 10% and at 15% of predicted work rate maximum were studied., Results: Umbilical artery Doppler deteriorated after exercise in patients with UPVI (pre PI 1.4 [0.35-2.14], post PI 1.64 [0.45-2.18]). Three (25%) had transient absent-end diastolic flow (AEDF) in umbilical artery, 2 of which developed early-onset intrauterine growth restriction (IUGR) with AEDF. Fetal cardiac output studies remained stable during the examinations., Conclusion: Submaximal steady state exercise had a transient deleterious effect in a subset of women with uteroplacental vascular insufficiency destined to develop early-onset IUGR.

Maximal voluntary ventilation (MVV) may be determined directly by the sprint method or calculated from pulmonary function data, using the functions MVV = forced expired volume in 1 sec (FEV(1)) x 35 or MVV = FEV(1) x 40. The purpose of this paper was to test the validity of the equation over a wide range of lung function in children. Cystic fibrosis (CF), a chronic lung disease where children typically have a wide range of pulmonary function, was chosen as the study requirement. Spirometric data from 332 children with CF who underwent pulmonary function testing between 1987-2000 were stratified according to disease severity, and box-plots comparing the ratio of MVV to FEV(1) for each category were generated. As results indicated that the equation underestimates true MVV proportionally to the degree of airflow limitation, a new function to predict MVV for this population was derived and tested. The new equation was derived using data from patients who were tested on odd-numbered days (group A). The validity of the new equation was then tested on the patients tested on even-numbered days (group B). To test its validity, the results were compared to the "gold standard" sprint values using a Bland and Altman plot. MVV was expressed as a function of FEV(1) and predicted FEV(1): MVV = 27.7(FEV(1)) + 8.8(PredFEV(1)) (R(2) = 0.98, P < 0.05). In this way, the accuracy of the new equation was confirmed. Whenever possible, we recommend MVV be determined by the sprint method in accordance with ATS guidelines. If this is not feasible, we recommend considering the new prediction equation., (Copyright 2003 Wiley-Liss, Inc.)

Objectives: To evaluate the effects of a 3-year home exercise program on pulmonary function and exercise tolerance in mildly to moderately impaired patients with cystic fibrosis (CF) and to assess whether regular aerobic exercise is a realistic treatment option., Study Design: Seventy-two patients with CF (7-19 years) were randomly assigned to an exercise group (a minimum of 20 minutes of aerobic exercise, at a heart rate of approximately 150 beats/min, 3 times weekly) or a control group (usual physical activity participation). Pulmonary function, exercise tolerance, clinical status, hospitalizations, and compliance with therapy were monitored during scheduled visits to the hospital's CF clinic., Results: Sixty-five patients were included in the analyses. The control group demonstrated a greater annual decline in percent of predicted forced vital capacity compared with the exercise group (mean slope +/- SD, -2.42 +/- 4.15 vs -0.25 +/- 2.81; P =.02), with a similar trend for forced expiratory volume in 1 second (-3.47 +/- 4.93 vs -1.46 +/- 3. 55; P =.07). Patients remained compliant with the exercise program over the study period. An improved sense of well-being was reported with exercise., Conclusions: Pulmonary function declined more slowly in the exercise group than in the control group, suggesting a benefit for patients with CF participating in regular aerobic exercise. Consistent compliance with the home exercise program and a self-reported positive attitude toward exercise provide further evidence of the feasibility and value of including an aerobic exercise program in the conventional treatment regimen of patients with CF.