How does heart rate recovery after sub-maximal exercise correlate with maximal exercise testing in children with CF?

Heart rate recovery in asthmastic children and adolescents after clinical field test

BACKGROUND

Inflammation caused by chronic lung disease in childhood may lead to delayed heart rate recovery (HRR) however, there is lack of evidence on HRR in this population. The aim was to assess HRR after functional capacity testing in asthmatic children and adolescents and to compare with severity and disease control.

METHOD

This was a study secondary to a randomized control trial. The modified shuttle test (MST) was performed to assess functional capacity and HRR. This is an externally cadenced test in which the distance walked is the outcome. HRR was assessed after MST and was defined as HR at exercise peak minus HR in the second minute after the end of exercise. Asthma control was assessed by the Asthma Control Test (ACT). Data normality was tested by Shapiro Wilk and the comparison between groups was made by Student's t test or Mann Whitney test for numerical variables, and by Chi-square test for categorical variables. Statistical significance was considered when p < 0.05. SPSS version 20 was used in the analyzes.

RESULTS

The sample included 77 patients diagnosed with asthma (asthma group - AG) who were regularly treated for asthma. Control group (CG) consisted of 44 volunteers considered healthy, matched in age and gender to AG. The median age of CG was 12 (10-14) years and in AG 11 (9-13 years) being classified as mild to moderate asthmatic, and 57% of the sample had controlled asthma by ACT. Distance walked in the CG was 952 ± 286 m and AG 799 ± 313 m, p = 0.001. HRR was more efficient in CG (79 ± 15 bpm) compared to AG (69 ± 12 bpm), p = 0.001. The mild (69 ± 12 beats) and severe (72 ± 15 beats) AG presented worse HRR compared to control group (79 ± 15 bpm), p < 0.05.

CONCLUSIONS

Asthmatic children and adolescents have delayed HRR after modified Shuttle test compared to their peers, suggesting that asthma leads to autonomic nervous system imbalance.

TRIAL REGISTRATION

Registered in Clinical Trials under number NCT02383069 and approved by the Universidade Nove de Julho - UNINOVE Research Ethics Committee, protocol number 738192/2014.

2014 year in review: Cystic fibrosis

In this article, we highlight cystic fibrosis (CF) research published in Pediatric Pulmonology during 2014, as well as related articles published in other journals.

Relationship between daily physical activity and aerobic fitness in adults with cystic fibrosis

Background

The best clinical practice to investigate aerobic fitness includes measurements obtained during cardiopulmonary exercise testing (CPET), however it remains an underutilised clinical measure in cystic fibrosis (CF). To investigate this further, different methods of quantifying exercise capacity in CF are required. The possibility that measuring physical activity (PA) by a portable accelerometer could be used to assess the CF aerobic state and could be added among the CPET surrogates has not been investigated. The aim of this study was to examine the relationship between PA and exercise fitness both at submaximal and maximal levels in clinically stable adults with CF.

Methods

Thirty CF patients (FEV₁ 71 ± 19% predicted) and fifteen healthy controls undertook an incremental CPET on a cycle ergometer. CPET-related measurements included: oxygen uptake (V’O₂), carbon dioxide production (V’CO₂), ventilatory profile, heart rate (HR) and oxygen pulse (V’O₂/HR) throughout exercise and at lactic threshold (LT) and peak. LT measures represent submaximal exercise related data. PA was assessed using the accelerometer SenseWear Pro3 Armband.

Results

Moderate (>4.8 metabolic equivalents (METS)) and moderate + vigorous (>7.2 METS) PA was related to V’O₂ (p = 0.005 and p = 0.009, respectively) and work rate (p = 0.004 and p = 0.002, respectively) at LT. Moderate PA or greater was positively related to peak V’O₂ (p = 0.005 and p = 0.003, respectively). Daily PA levels were similar in CF and healthy controls. Except for peak values, V’O₂ profile and the V’O₂ at LT were comparable between CF and healthy controls.

Conclusions

In adult CF patients daily PA positively correlated with aerobic capacity. PA measurements are a valuable tool in the assessment of exercise performance in an adult CF population and could be used for interventional exercise trials to optimize exercise performance and health status. PA levels and parameters obtained at submaximal exercise are similar in CF and in healthy controls.

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-015-0036-9) contains supplementary material, which is available to authorized users.