Reduced fat oxidation rates during submaximal exercise in adolescents with Crohn's disease.

BACKGROUND: Children with Crohn's disease (CD) suffer from malnutrition. Understanding substrate utilization during exercise may help patients with CD sustain a healthy active lifestyle without compromising nutrition. The aim of this study was to determine whether substrate utilization and bioavailability during exercise are altered in children with CD compared with controls. METHODS: Seven children with CD (mean age ± SD: 15.2 ± 2.3 yr) and 7 controls (14.4 ± 2.3 yr) were matched by sex and biological age. Participants completed 60 minutes of cycling at an intensity equivalent to 50% of their peak mechanical power. Rates of total fat and carbohydrate (CHO) oxidation, the amount of fat and CHO oxidized, and the contribution of fat and CHO to total energy expenditure were calculated from expired gases collected during exercise. Blood was collected before, during, and at the end of exercise and analyzed for insulin, free fatty acids, and glucose. RESULTS: Whole-body fat oxidation rate (expressed in mg · kg(-1) of body weight per min) during exercise was lower in children with CD (5.8 ± 1.0) compared with controls (8.0 ± 2.2, P < 0.05). Children with CD relied significantly more on CHO, with approximately 10% greater contribution toward total energy expenditure (P < 0.05) than controls. There were no differences in plasma insulin, free fatty acids, or glucose between the groups. CONCLUSIONS: Fat metabolism during exercise seems to be impaired in children with CD. A greater reliance on CHO is required to meet the energy demands of submaximal exercise.

Inflammatory and growth factor response to continuous and intermittent exercise in youth with cystic fibrosis.

BACKGROUND: Children with cystic fibrosis (CF) tend to suffer from chronic systemic inflammation and may have impaired growth associated with muscle catabolism. Therefore, investigating which type of exercise can elicit an anabolic response with minimal inflammation is of clinical value. METHODS: Twelve children with CF (mean±SD; age: 14.7±2.3 years, predicted FEV(1): 90.0±21.6%) and biological age-matched controls (age: 13.9±2.1 years) completed moderate-intensity, continuous exercise (MICE) and high-intensity, intermittent exercise (HIIE) on separate days. During each exercise, blood was drawn at various time points and analyzed for immune cells, inflammatory cytokines, and growth mediators. RESULTS: At rest, children with CF had higher concentrations of neutrophils and IL-6 compared with controls. In children with CF, HIIE did not affect immune cell subsets or cytokines: TNF-α, IL-6, and tumor necrosis factor-like weak inducer of apoptosis (TWEAK). All immune cell subsets and IL-6 increased significantly with MICE in both groups. Growth hormone (GH) increased with both types of exercise, with a greater change from rest during MICE. CONCLUSIONS: HIIE was a sufficient stimulus to increase GH in children with CF, without affecting systemic inflammation.

The effects of acute and chronic exercise on inflammatory markers in children and adults with a chronic inflammatory disease: a systematic review.

BACKGROUND: Chronic inflammatory diseases strike millions of people all over the world, and exercise is often prescribed for these patients to improve overall fitness and quality of life. In healthy individuals, acute and chronic exercise is known to alter inflammatory markers; however, less is known about these effects in patients with a chronic inflammatory disease. OBJECTIVE: The purpose of this review is to clearly define the effects of acute and chronic exercise on inflammatory markers in patients compared with healthy controls to determine whether exercise elicits an abnormal inflammatory response in those patients. DATA SOURCES: A literature search was conducted through MEDLINE and EMBASE (until January 2009). STUDY SELECTION: A distinction was made between children and adults, acute (i.e., single exercise session) and chronic exercise (i.e., training) and endurance and resistance exercise. To evaluate and compare the exercise responsiveness of various reported inflammatory markers, pre- to post-test effect sizes were calculated. DATA EXTRACTION: A methodological quality scoring as well as an assessment of the quality of exercise paradigms were both made. RESULTS: In total, 19 studies were included in this systematic review (children, n=7; adults, n=12). Of these, 7 were acute exercise studies in children, 8 were acute exercise in adults, 5 were chronic endurance exercise training studies, and I was a chronic resistance exercise training study. No exercise training studies were found involving children. Single bouts of exercise might elicit an aggravated inflammatory response in patients; this was reported for patients with type I diabetes mellitus, cystic fibrosis and chronic obstructive pulmonary disease. More severely affected patients may experience a more aggravated inflammatory response. Levels ofinflammatory markers, principally IL-6 but also T-cells, total leukocytes and lymphocytes, remained elevated longer into the recovery period following an acute bout of exercise in patients compared with healthy controls. Evidence was found that chronic endurance exercise training programs can attenuate systemic inflammation in patients with chronic heart failure and type 2 diabetes mellitus. CONCLUSIONS: In patients with a chronic inflammatory disease, both acute and chronic exercise might elicit different inflammatory responses (i.e., exaggerated after acute exercise & attenuated after training) compared to healthy matched controls. However, the results reveal a major gap in our knowledge regarding the effects of acute and chronic exercise on inflammatory markers in patients with a chronic inflammatory disease. Results are often inconsistent, and differences in training programs (intensity, frequency and duration), heterogeneity of disease populations studied, and analytic methods may be just some of the causes for these discrepancies. To optimize exercise prescriptions and recommendations for patients with a chronic inflammatory disease, more research is needed to define the nature of physical activity that confers health benefits without exacerbating underlying inflammatory stress associated with disease pathology.