Energy cost of physical activity in cystic fibrosis

Nutritional assessment in adults with cystic fibrosis

OBJECTIVES

Clinical experience with patients with cystic fibrosis (CF) suggests a nutritional risk in this population. In addition to the lung pathology, a main pathophysiologic concern is the viscous mucus blocking pancreatic ducts, leading to reduced production of pancreatic enzymes. Therefore, maldigestion and consequently malabsorption (particularly fat and fat-soluble vitamins) occur, resulting in steatorrhea, vitamin deficiencies, and subsequently manifest malnutrition. The aim of this study was to investigate the nutritional status and determine the prevalence of malnutrition in an adult Swiss CF cohort.

METHODS

This was an observational cohort study in which the nutritional status and dietary habits of patients with CF and healthy controls were compared. Assessment was based on the nutritional risk screening (NRS-2002), dietary habits (7-d dietary record), body composition (bioelectrical impedance analysis), anthropometrics, resting energy expenditure (REE; indirect calorimetry), and physical or mental function (hand-grip strength, Short Form-36 v2).

RESULTS

Nineteen patients (15 men, mean age 32 y) and 15 controls (8 men, mean age 49 y) were included. Eight patients (42%) were at nutritional risk (NRS-2002 ≥3). Patients had higher energy intake/body weight (P = 0.021) with lower body fat percentage (P < .001), body mass index (P = 0.030), and physical/mental health scores (P < 0.001) than controls. Energy intake was higher than REE in patients (P = 0.003), but not in controls (P = 0.373).

CONCLUSIONS

Prevalence of malnutrition was high in this CF cohort, coinciding with low body fat percentage and low body mass index despite high energy and protein intake. Energy requirements of patients with CF should be estimated as approximately twice the Harris-Benedict REE and 1.7 times indirect calorimetry REE, while ensuring adequate intake of pancreatic enzymes.

Self-reported exercise and longitudinal outcomes in cystic fibrosis: a retrospective cohort study

BACKGROUND

Cystic fibrosis (CF) is characterized by recurrent respiratory infections and progressive lung disease. Whereas exercise may contribute to preserving lung function, its benefit is difficult to ascertain given the selection bias of healthier patients being more predisposed to exercise. Our objective was to examine the role of self-reported exercise with longitudinal lung function and body mass index (BMI) measures in CF.

METHODS

A total of 1038 subjects with CF were recruited through the U.S. CF Twin-Sibling Study. Questionnaires were used to determine exercise habits. Questionnaires, chart review, and U.S. CF Foundation Patient Registry data were used to track outcomes.

RESULTS

Within the study sample 75% of subjects self-reported regular exercise. Exercise was associated with an older age of diagnosis (p = 0.002), older age at the time of ascertainment (p < 0.001), and higher baseline FEV1 (p = 0.001), but not CFTR genotype (p = 0.64) or exocrine pancreatic function (p = 0.19). In adjusted mixed models, exercise was associated with both a reduced decline in FEV1 (p < 0.001) and BMI Z-score (p = 0.001) for adults, but not children aged 10-17 years old.

CONCLUSIONS

In our retrospective study, self-reported exercise was associated with improved longitudinal nutritional and pulmonary outcomes in cystic fibrosis for adults. Although prospective studies are needed to confirm these associations, programs to promote regular exercise among individuals with cystic fibrosis would be beneficial.

Physical activity levels of patients with cystic fibrosis hospitalised with an acute respiratory exacerbation

BACKGROUND

The physical activity levels of adult patients with cystic fibrosis hospitalised for an acute respiratory exacerbation is unknown.

METHODS

A prospective observational study was undertaken. Physical activity levels were measured for a 24-h period using an activity monitor (SenseWear(®) Pro 3) during hospitalisation for an acute respiratory exacerbation and one month post-discharge. Measures of exercise tolerance and muscle strength were also recorded.

RESULTS

Twenty-four patients completed the study. Most outcomes significantly increased from hospitalisation to one month post-discharge. Time spent doing physical activity (≥3 METs) increased from a mean ± SD of 95 ± 58 to 209 ± 111 min.

CONCLUSIONS

Hospitalisation for an acute respiratory exacerbation was associated with less time spent performing physical activity compared to one month post-discharge. Physical activity levels were higher than anticipated, even during hospitalisation, suggesting an increased metabolic rate may have contributed to the physical activity levels documented. Activity level definitions for moderate intensity exercise that are based on higher MET levels seemed more appropriate in this patient setting.

CLINICAL TRIAL REGISTRY

Australian New Zealand Clinical Trials Registry Number: ACTRN12610000595011.

Exercise as part of a cystic fibrosis therapeutic routine

The role of exercise in cystic fibrosis (CF) is well established, and over the last three decades it has become an important component in the management of all individuals with CF. The role of exercise as a prognostic indicator or therapeutic tool is an important area of research interest in CF care internationally. This article summarizes the currently available evidence regarding exercise capacity in CF, the potential effects of exercise on health outcomes in CF and the challenges faced when trying to incorporate exercise into a CF therapeutic routine, and highlights some methods to facilitate the incorporation of exercise into CF therapeutic routines.

Exercise metabolism during moderate-intensity exercise in children with cystic fibrosis following heavy-intensity exercise

Muscle metabolism is increased following exercise in healthy individuals, affecting exercise metabolism during subsequent physical work. We hypothesized that following heavy-intensity exercise (HIE), disease factors in children with cystic fibrosis (CF) would further exacerbate exercise metabolism and perceived exertion during subsequent exercise. Nineteen children with CF (age, 13.4 ± 3.1 years; 10 female) and 19 healthy controls (age, 13.8 ± 3.5 years; 10 female) performed 10 bouts of HIE interspersed with 1 min of recovery between each bout. Three minutes later participants completed a 10-min moderate-intensity exercise (MIE) test (test 1). The MIE test was subsequently repeated 1 h (test 2) and 24 h (test 3) later. Each MIE test was identical and participants exercised at individualized work rates, calibrated by an initial graded maximal cardiopulmonary exercise test, while metabolic and perceived exertion measurements were taken. Following HIE, mixed-model ANOVAs showed a significant difference in oxygen uptake (VO2) and rating of perceived exertion (RPE) between the 2 groups across the MIE tests (p < 0.01). In controls, VO2 (L·min–1) and RPE decreased significantly from test 1 to test 2 (p < 0.01) and test 2 to test 3 (p < 0.05). However, in children with CF, VO2 (L·min–1) increased significantly from test 1 to test 2 (p < 0.01), while RPE did not differ, both VO2 and RPE decreased significantly from test 2 to test 3 (p < 0.01). In conclusion, following HIE the metabolic and perceptual responses to MIE in both groups decreased 24 h later during test 3. These data show that children with mild-to-moderate CF have the capability to perform HIE and 24 h allows sufficient time for recovery.

Gaming console exercise and cycle or treadmill exercise provide similar cardiovascular demand in adults with cystic fibrosis: a randomised cross-over trial

QUESTION

Does exercise using a gaming console result in similar cardiovascular demand and energy expenditure as formally prescribed exercise in adults with cystic fibrosis? How do these patients perceive gaming console exercise?

DESIGN

Randomised cross-over trial with concealed allocation and intention-to-treat analysis.

PARTICIPANTS

19 adults with cystic fibrosis admitted to hospital for treatment of a pulmonary exacerbation.

INTERVENTION

Participants underwent two 15-minute exercise interventions on separate days; one involving a gaming console and one a treadmill or cycle ergometer.

OUTCOME MEASURES

Cardiovascular demand was measured using heart rate and rating of perceived exertion (RPE). Energy expenditure was estimated using a portable activity monitor. Perception (enjoyment, fatigue, workload, effectiveness, feasibility) was rated using a horizontal 10-cm visual analogue scale.

RESULTS

There was no significant difference in average heart rate (mean difference 3 beats/min, 95% CI -3 to 9) or energy expenditure (0.1 MET, 95% CI -0.3 to 0.5) between the two interventions. Both interventions provided a 'hard' workout (RPE ∼15). Gaming console exercise was rated as more enjoyable (mean difference 2.6 cm, 95% CI 1.6 to 3.6) than formal exercise but they didn't differ significantly in fatigue (-1.0 cm, 95% CI -2.4 to 0.3), perceived effectiveness (-0.4 cm, 95% CI -1.2 to 0.3), or perceived feasibility for inclusion in routine management (0.2 cm, 95% CI -0.7 to 1.1).

CONCLUSION

Gaming console exercise provides a similar cardiovascular demand as traditional exercise modalities. It is feasible that adults with cystic fibrosis could include gaming console exercise in their exercise program.

TRIAL REGISTRATION

ACTRN12610000861055.

Effects of acupuncture-like transcutaneous electrical nerve stimulation on children with asthma

OBJECTIVE

To evaluate the effects of acupuncture-like transcutaneous electrical nerve stimulation (AL-TENS) on children with asthma.

METHODS

After an 8-week run-in period, the experimental group were assigned to treatment with AL-TENS, whereas the control group did not receive AL-TENS. A total of 43 children with asthma were recruited from a hospital and an elementary school. All the cases had been diagnosed as having asthma by physicians. The outcome measures included pulmonary function tests (PFTs), heart rate turbulence (HRT), heart rate variability (HRV), and pediatric asthma quality-of-life questionnaire (PAQLQ).

RESULTS

After 8 weeks of AL-TENS, there were no significant differences on forced vital capacity (FVC), FEV₁/FVC, and peak expiratory flows (PEFs) between the two groups. The HRT is the physiological, biphasic response of the sinus node to premature ventricular contractions. In the experimental group, the mean HRT was statistically significant between pretest and posttest. The HRV and the PAQLQ showed no difference, but in the experimental group, the subscale of the PAQLQ (particularly activity) improved significantly more than the pretest scores. Furthermore, there were no differences in PFTs and HRV after 8 weeks of AL-TENS between the two groups.

CONCLUSIONS

The PAQLQ activities of the experimental group improved significantly more than those of the control group. Reasons may include: 1) the asthma cases were stable and the cases were on stable status and 2) the degree of airway remodeling was less. It is suggested that in the future, treatment frequency and the long-term follow-up for evaluating the effects of AL-TENS on children with asthma should also be considered.

Substrate utilization during and after exercise in mild cystic fibrosis

PURPOSE

To determine substrate utilization and energy expenditure during maximal and submaximal exercise and recovery in adolescents with cystic fibrosis (CF) and healthy age-matched controls (C).

METHODS

Ten clinically stable CF patients (four girls, six boys; age = 10-22 yr) were matched by body mass index, age, gender, and Tanner stage to healthy controls. Subjects completed VO(2peak) testing and submaximal exercise (20 min) on a cycle ergometer at a relative intensity of 50% VO2(peak) and at an absolute power output (PO). Metabolic parameters were assessed during exercise and recovery (20 min).

RESULTS

Similar respiratory quotient (RQ) values occurred in both groups during maximal exercise and recovery, despite differences in the maximal PO [CF = 114 (60-180) W and C = 171 (105-280) W, P = 0.006], the total work completed [CF = 27 (9.0-54.3) kJ and C = 55 (25.3-126.5) kJ, P = 0.008], or the VO(2peak) value attained [CF = 30.6 (8.5-45.2) mL kg(-1) min(-1) and C = 40.6 (29-64.5) mL kg(-1) min(-1), P = 0.027]. Submaximal exercise at the same absolute PO resulted in similar RQ values during exercise and recovery despite higher heart rates and average VO2 [CF = 18.8 (9.3-28.7) mL kg(-1) min(-1) and C = 15.2 (6.5-20.1) mL kg(-1)min(-1), P = 0.031] values in CF adolescents, and submaximal exercise at the same relative intensity also resulted in similar RQ values despite significantly greater average PO in the C group [CF = 38.7 (12.3-80) W and C = 67.8 (25.5-140) W, P = 0.039]. Excess postexercise oxygen consumption (EPOC) was greater in CF [2.79 (1.14-5.24) L O2] than C [1.46 (0.56-2.80) L O2] after submaximal exercise at a fixed PO (P = 0.036) but not after the relative exercise bout.

CONCLUSIONS

Habitual physical activity participation does not warrant adjustment of macronutrient intake ratios in adolescents with mild to moderate CF, but total caloric intake may need to be increased based on the level of EPOC and upon the intensity and the duration of the habitual activity.

[Analysis of energy expenditure in adults with cystic fibrosis: comparison of indirect calorimetry and prediction equations]

OBJECTIVE

Undernutrition, which implies an imbalance between energy intake and energy requirements, is common in patients with cystic fibrosis. The aim of this study was to compare resting energy expenditure determined by indirect calorimetry with that obtained with commonly used predictive equations in adults with cystic fibrosis and to assess the influence of clinical variables on the values obtained.

PATIENTS AND METHODS

We studied 21 patients with clinically stable cystic fibrosis, obtaining data on anthropometric variables, hand grip dynamometry, electrical bioimpedance, and resting energy expenditure by indirect calorimetry. We used the intraclass correlation coefficient (ICC) and the Bland-Altman method to assess agreement between the values obtained for resting energy expenditure measured by indirect calorimetry and those obtained with the World Health Organization (WHO) and Harris-Benedict prediction equations.

RESULTS

The prediction equations underestimated resting energy expenditure in more than 90% of cases. The agreement between the value obtained by indirect calorimetry and that calculated with the prediction equations was poor (ICC for comparisons with the WHO and Harris-Benedict equations, 0.47 and 0.41, respectively). Bland-Altman analysis revealed a variable bias between the results of indirect calorimetry and those obtained with prediction equations, irrespective of the resting energy expenditure. The difference between the values measured by indirect calorimetry and those obtained with the WHO equation was significantly larger in patients homozygous for the DeltaF508 mutation and in those with exocrine pancreatic insufficiency.

CONCLUSIONS

The WHO and Harris-Benedict prediction equations underestimate resting energy expenditure in adults with cystic fibrosis. There is poor agreement between the values for resting energy expenditure determined by indirect calorimetry and those estimated with prediction equations. Underestimation was greater in patients with exocrine pancreatic insufficiency and patients who were homozygous for DeltaF508.

Energy cost of activity and exercise in children and adolescents with cystic fibrosis

In cystic fibrosis (CF), perturbations of total daily energy expenditure (TDEE) may be a major determinant of altered nutrition and growth. Measurement of TDEE is problematic, though the flex-heart rate method (FHRM) provides a close estimation of TDEE, as compared to the cost-prohibitive, gold standard, the double-labeled water method, and permits estimates of the energy cost of daily activities (ECA) above resting energy expenditure (REE). We hypothesize that alterations in ECA affects TDEE in CF.

PURPOSE

To measure components of TDEE in adolescents with CF and normal lung function compared with controls, and to determine whether ECA can be improved by diet and exercise.

METHODS

Clinically stable CF subjects (aged 9-13, n=12) and age- and gender-matched controls (n=13) had repeated measurements of TDEE by FHRM, REE, and maximal cardiopulmonary exercise testing (CPET) during a 6-week exercise and diet program.

RESULTS

While the mean REE was similar in both groups, ECA was significantly lower in CF adolescents as compared to controls (p=0.02). During CPET, maximal exercise in CF was characterized by hyperventilation, which was unrelated to ventilation-perfusion mismatching. There were no changes in REE after dietary intervention.

CONCLUSION

ECA in CF adolescents with normal lung function is lower when compared to healthy controls. These findings support the hypothesis that clinically stable patients with CF have inefficient energy metabolism or alternatively conserve energy during activities of daily living.

[Technical aspects and relevance of energy expenditure and physical activity assessment in clinical research for cystic fibrosis patients]

Cystic fibrosis (CF) is characterized by deteriorating lung function and mal-digestion, which result in growth failure and/or under-nutrition. Several factors, alone or combined, contribute to malnutrition in CF: poor energy intake, elevation of energy loss as a result of malabsorption, increasing resting energy expenditure due to genetic mutation and/or pulmonary exacerbation. Several techniques have been used to assess energy expenditure and physical activity in order to better understand mechanisms of malnutrition in CF and follow therapeutic interventions. Indirect calorimetry (IC) studies have shown that resting energy expenditure (REE) was 10-22% higher than predictive values. This increase could be attributed to chronic inflammation as a result of Pseudomonas aeruginosa (PA) infection. Indeed, intravenous antibiotic therapy decreases REE. Doubly labelled water technique and heart rate monitoring calibrated against IC techniques shows that total energy expenditure (TEE) was not different than in healthy children. Physical activity level assessed by the ratio TEE-REE is also not different between CF of healthy children. Recently, new accelerometry technics, easier to use and less invasive have been successfully used in order to assess physical activity level in CF. Precise and ambulatory assessment of energy expenditure and physical activity permit to check and adapt dietary allowances in CF. These techniques could be simultaneously used and be helpful to assess efficacy of intervention studies.

Assessment of nutritional status in adult patients with cystic fibrosis: Whole-body bioimpedance vs body mass index, skinfolds, and leg-to-leg bioimpedance

OBJECTIVE

To investigate whether body mass index (BMI) or body fat percentage estimated from BMI, skinfolds, or leg-to-leg bioimpedance are good indicators of nutritional status in adult patients with cystic fibrosis. Body fat percentage measured by whole-body bioimpedance was used as the reference method.

DESIGN

Cross-sectional study using four methods to estimate body fat percentage. All patients filled out a food frequency and a physical activity questionnaire for assessment of their habitual food intake and energy requirements, respectively.

SUBJECTS/SETTING

Thirty-five adult patients (23 men/12 women) with cystic fibrosis, age range 18 to 46 years, were measured during their yearly visit at the outpatient clinic of the Cystic Fibrosis Center in Utrecht, the Netherlands.

STATISTICAL ANALYSIS

Mean+/-standard deviation was calculated for all measurements and 95% confidence intervals for differences between methods. Bland-Altman plots were used to assess differences between the measures of body composition and Pearson correlation coefficients were calculated to determine the relationships between them, and between the energy requirements and the energy intakes.

RESULTS

For men the whole-body body fat percentage reference was 14.1%+/-3.0, body fat percentage estimated from BMI was 15.8%+/-4.3, body fat percentage estimated from skinfolds was 8.6%+/-4.8, and body fat percentage estimated from leg-to-leg bioimpedance was 13.1%+/-4.9. For women the whole-body body fat percentage reference was 24.0%+/-5.9, body fat percentage estimated from BMI was 25.1%+/-4.0, body fat percentage estimated from skinfolds was 17.0%+/-4.8, and body fat percentage estimated from leg-to-leg bioimpedance was 25.0%+/-6.9. Body fat percentage estimated from BMI and body fat percentage estimated from skinfolds were significantly different from the reference value for body fat percentage (P <.05). The correlation coefficients between the reference body fat percentage and body fat percentage estimated from BMI, from skinfolds, and from leg-to-leg bioimpedance were all more than 0.72. In all but one patient, nutritional status was correctly assessed by BMI: those with a BMI less than 18.5 had body fat percentage less than 10% (men) or less than 20% (women). The mean energy intake of the men was 141% of the Recommended Dietary Allowance as proposed in European and Dutch guidelines. The mean energy intake of the women was 94% of the Recommended Dietary Allowance.

CONCLUSIONS

A simple calculation of BMI is adequate to diagnose nutritional status in adult patients with cystic fibrosis. Bioimpedance measurements are only needed when nutritional therapy specifically focuses on lean body mass.

Energetic cost of physical activity in cystic fibrosis children during Pseudomonas aeruginosa pulmonary exacerbation

Chronic pulmonary infection by Pseudomonas aeruginosa is observed in 50% of patients with cystic fibrosis and requires the use of recurrent intravenous therapy. A decrease of resting energy expenditure (REE) and an increase of physical activity (PA) after intravenous anti-P. aeruginosa therapy (IVAT) is observed while total energy expenditure (TEE) does not change. A decrease in the energetic cost of physical activity (ECPA) could be hypothesized but has never been studied. Our aim was to assess the evolution of ECPA after home IVAT in both standardized condition at hospital and in free-living condition twice before and after IVAT. Sixteen CF patients (nine boys, seven girls) chronically colonized by P. aeruginosa with a mean age of 12.1+/-2.3 years (range 7.1-14.6) were studied before and after IVAT. Each patient passed throughout a visit in hospital: weight, height and fat-free mass were measured. Then, energy expenditure (EE) measured by indirect calorimetry and heart rate (HR) were simultaneously recorded at different levels of PA: REE, and at different intensity of physical activities on a cycloergometer using an incremental increase of the power brake force. Physical activity energy expenditure (PAEE) was computed in laboratory condition using PAEE=EE-BEE (basal energy expenditure). Linear regression between PAEE and power brake force was fitted for each patient before and after IVAT. ECPA in standardized conditions was compared at different range of power brake force using area under the curve (AUC). After coming back at home, 24 h TEE using the heart rate monitoring technique and PA by triaxial accelerometry were simultaneously measured in free-living condition for 24 h during a school day. ECPA in free-living conditions was compared by the ratio PAEE:PA where PAEE=DEE-REE (DEE=daily energy expenditure). After IVAT, median AUC between 60 and 90 W in standardized condition decreased significantly by -15.4% (median 14.9, range 8.8-30.3 vs. median 12.6, range 8.5-17.6; P<0.05, Wilcoxon rank test) while the decrease for lower range of power work load did not reach significance. Spearman correlation was significant between variations of forced expiratory volume in 1 s and variation of AUC at 30-60 W before and after IVAT in standardized condition. In free-living conditions, ratio PAEE/PA did not vary significantly (median 3.4, range 1.6-6.4 vs. median 2.8, range 1.4-4.8; NS). Our data demonstrate a decrease of ECPA after IVAT in standardized conditions for moderate level of PA (60-90 W), but not in free-living conditions. The decrease of ECPA was probably due to a decrease in the energetic cost of breathing after IVAT, that is particularly relevant to promote PA in CF patients.

Energy balance in cystic fibrosis when stable and during a respiratory exacerbation

BACKGROUND AND AIMS

Undernutrition is common in young adult patients with cystic fibrosis (CF) and implies an imbalance between energy intake and total energy expenditure (TEE). The aim of this study was to measure energy intake and TEE expenditure in a group of patients when they were clinically stable at home and during an exacerbation of respiratory symptoms when they were in hospital receiving intravenous antibiotics.

METHODS

Eleven patients aged between 15 and 40 years with moderate respiratory disease, mean FEV(1) 51.4% predicted took part. An exacerbation was defined as>15% decrease in FEV(1), an increase in sputum production and a decision to treat in hospital with intravenous antibiotics. Resting energy expenditure (REE) was measured using indirect calorimetry and energy intake by 3 day food diaries. TEE expenditure was measured using 24 h heart rate and doubly isotopically labelled water.

RESULTS

REE was higher at the beginning of an exacerbation than the end, P<0.05. There was no significant difference in TEE during the stable period compared to the exacerbation 10.53(2.39)MJ/day compared to 8.77(1.59)MJ/day using doubly isotopically labelled water. There was no difference in energy intake during the exacerbation compared to the stable period, 11.19(2.31)MJ/day compared to 11.77(2.30)MJ/day.

CONCLUSIONS

There was no difference in TEE and energy intake when patients were unwell in hospital compared to when they were stable at home despite an increase in REE.

Gender differences in habitual activity in children with cystic fibrosis

AIMS

(1) To compare habitual activity levels in prepubescent and pubescent boys and girls with different degrees of CF lung disease severity and healthy controls. (2) To assess the relation between habitual activity levels and measures of fitness, lung function, nutrition, pancreatic status, and quality of life.

METHODS AND RESULTS

A total of 148 children (75 girls and 73 boys) with CF and matched controls were studied. Regardless of disease severity, there were no differences in habitual activity between prepubescent boys and girls with CF. Pubescent boys with CF were significantly more active than girls with the same degree of disease severity. There were no significant differences in habitual activity between prepubescent children with CF and controls. Pubescent children with mild CF were significantly more active than controls, but those with moderate to severe disease were less active than controls. The best correlates with habitual activity levels were anaerobic power, aerobic capacity, and quality of life. In children with moderate to severe disease, nutrition status correlated significantly with activity levels. The impact of pancreatic status on activity levels and other measures of fitness was most apparent in pubescent girls.

CONCLUSION

Gender differences in habitual activity were evident only after the onset of puberty. The impact of pancreatic insufficiency on measures of fitness and habitual activity was greatest in pubescent females. The reason for this gender difference may be an interplay of genetic, hormonal, and societal factors and is the focus of a longitudinal study.