What is the real impact of upper limb cast immobilisation on activity-related energy expenditure in children?

BACKGROUND: Upper limb fractures and subsequent cast immobilisation constitute a potential cause of reduction in childhood levels of physical activity (PA), with subsequent decrease of energy consumption. The main objective of this study was thus to quantify the decrease of activity-related energy expenditure (AEE) due to upper limb cast immobilisation. METHODS: We conducted a longitudinal matched case-control study that included 35 children and teenagers with a first episode of upper limb fracture and 35 healthy cases. PA was assessed during cast immobilisation by accelerometer. AEE was the calculated using an equation based on the total counts per day measured by accelerometers. RESULTS: AEE in children and teenagers with upper limb fractures was estimated to be 7.4 % lower than healthy controls. The mean difference corresponded to 1.35 kcal/kg per mean valid recorded time (750 min), that is, the waking hours. When converted in kcal per mean subjects' weight, the difference in AEE amounted 63.5 kcal/day, which corresponds approximately to 26 min of walking at a speed of 4 km/hours. In comparison with the mean AEE in healthy controls (18.2 kcal/kg), the noted decrease (1.35 kcal/kg) represents only 7.4 % of AEE. CONCLUSION: Reduction of AEE in children and teenagers with upper limb fractures may lead to a slight positive energy balance, as there is usually no compensatory reduction of energy intake. An increase of light PA has to be counselled in this situation or patients should be advised to reduce their energy intake during the immobilisation period. LEVEL OF EVIDENCE: Level I: high-quality prospective study (all patients were enrolled at the same point in their disease with ≥80 % follow-up of enrolled patients).

Adapting the "Chester step test" to predict peak oxygen uptake in children.

AIM OF THE STUDY: Maximal exercise testing may be difficult to perform in clinical practice, especially in obese children who have low cardiorespiratory fitness and exercise tolerance. We aimed to elaborate a model predicting peak oxygen consumption (VO2) in lean and obese children with use of the submaximal Chester step test. METHODS: We performed a maximal step test, which consisted of 2-minute stages with increasing intensity to exhaustion, in 169 lean and obese children (age range: 7-16 years). VO2 was measured with indirect calorimetry. A statistical Tobit model was used to predict VO2 from age, gender, body mass index (BMI) z-score and intensity levels. Estimated VO2peak was then determined from the heart rate-VO2 linear relationship extrapolated to maximal heart rate (220 minus age, in beats.min-1). RESULTS: VO2 (ml/kg/min) can be predicted using the following equation: VO2 = 22.82 - [0.68*BMI z-score] - [0.46*age (years)] - [0.93*gender (male = 0; female = 1)] + [4.07*intensity level (stage 1, 2, 3 etc.)] - [0.24*BMI z-score *intensity level] - [0.34*gender*intensity level]. VO2 was lower in participants with high BMI z-scores and in female subjects. CONCLUSION: The Chester step test can assess cardiorespiratory fitness in lean and obese children in clinical settings. Our adapted equation allows the Chester step test to be used to estimate peak aerobic capacity in children.

Stairs instead of elevators at workplace: cardioprotective effects of a pragmatic intervention.

BACKGROUND: Population strategies to increase physical activity are an essential part of cardiovascular disease prevention. However, little data exist on lifestyle interventions that are easy to integrate into everyday life such as using stairs instead of elevators at the workplace. DESIGN: Pre and postintervention study. METHODS: A 12-week promotional campaign for stair use consisting in posters and floor stickers at the point of choice between stairs and elevators at each hospital floor was organized in a university hospital building. In 77 selected employees with an inactive lifestyle, physical activity, aerobic fitness, anthropometrics, blood pressure, lipids, insulin sensitivity, and C-reactive protein were assessed at baseline, 12 weeks, and 6 months. RESULTS: During the intervention median daily number of ascended and descended one-story staircase units was 20.6/day (14.2-28.1) compared with 4.5/day (1.8-7.2) at baseline (P<0.001). At 12 weeks, estimated maximal aerobic capacity had increased by 9.2±15.1% (P<0.001) corresponding with approximately 1 MET. There were significant declines in waist circumference (-1.7±2.9%), weight (-0.7±2.6%), fat mass (-1.5±8.4%), diastolic blood pressure (-1.8±8.9%), and low-density lipoprotein cholesterol (-3.0±13.5%). At 6 months, the median daily number of ascended and descended one-story staircase units had decreased to 7.2 (3.5-14.0). Benefits on estimated maximal aerobic capacity (+5.9±12.2%, P=0.001) and fat mass (-1.4±8.4%, P=0.038) persisted. CONCLUSION: Encouraging stair use at work is effective for improving fitness, body composition, blood pressure, and lipid profile in asymptomatic individuals with an inactive lifestyle and thus may be a simple way to significantly reduce cardiovascular disease risk at the population level.