Self‐report use‐of‐time tools for the assessment of physical activity and sedentary behaviour in young people: systematic review

Regular physical activity and limiting extended periods of sitting are two behaviours critical for the prevention of obesity in young people. The purpose of the systematic review was to synthesize the psychometric evidence for self‐report use‐of‐time tools that assess these behaviours. Articles were retrieved that reported reliability and/or validity for use‐of‐time tools in participants aged 18 years or under. Outcome variables were physical activity, sedentary behaviour and energy expenditure. Study quality was appraised, and the results summarized narratively. Sixteen studies and six different tools were identified. The tools were the Previous Day Physical Activity Recall, the Three‐Day Physical Activity Recall, the Physical Activity Interview, the Computerized Activity Recall, the Activitygram, and the Multimedia Activity Recall for Children and Adolescents. Overall, tools indicated moderate validity compared with objective and criterion comparison methods. Generally, validity correlation coefficients were in the range of 0.30–0.40. Correlation coefficients for test–retest reliability ranged widely from 0.24 to 0.98. Conclusion: Use‐of‐time tools have indicated moderate reliability and validity for the assessment of physical activity and energy expenditure. Future research should focus on using criterion methods and on validating specifically for sedentary behaviour outcomes. Implementation of these tools for population surveillance should be considered.     

Evaluation of activity monitors in manual wheelchair users with paraplegia

Abstract

Objective: The aim of this study was to evaluate the performance of SenseWear^® (SW) and RT3 activity monitors (AMs) in estimating energy expenditure (EE) in manual wheelchair users (MWUs) with paraplegia for a variety of physical activities.

Methods: Twenty-four subjects completed four activities including resting, wheelchair propulsion, arm-ergometry exercise, and deskwork. The criterion EE was measured by a K4b2 portable metabolic cart. The EE estimated by the SW and RT3 were compared with the criterion EE by the absolute differences and absolute percentage errors. Intraclass correlations and the Bland and Altman plots were also used to assess the agreements between the two AMs and the metabolic cart. Correlations between the criterion EE and the estimated EE and sensors data from the AMs were evaluated.

Results: The EE estimation errors for the AMs varied from 24.4 to 125.8% for the SW and from 22.0 to 52.8% for the RT3. The intraclass correlation coefficients (ICCs) between the criterion EE and the EE estimated by the two AMs for each activity and all activities as a whole were considered poor with all the ICCs smaller than 0.75. Except for deskwork, the EE from the SW was more correlated to the criterion EE than the EE from the RT3.

Conclusion: The results indicate that neither of the AMs is an appropriate tool for quantifying physical activity in MWUs with paraplegia. However, the accuracy of EE estimation could be potentially improved by building new regression models based on wheelchair-related activities.     

Acute renal failure potentiates brain energy dysfunction elicited by methylmalonic acid

The influence of acute renal failure induced by gentamicin administration on the effects of MMA on mitochondrial respiratory chain complexes, citrate synthase, succinate dehydrogenase and creatine kinase activities in cerebral cortex and kidney of young rats were investigated. Animals received one intraperitoneal injection of saline or gentamicin (70 mg/kg). One hour after, the animals received three consecutive subcutaneous injections of MMA (1.67 μmol/g) or saline (11 h interval between injections) and 60 min after the last injection the animals were killed. Acute MMA administration decreased creatine kinase activity in both tissues and increased complexes I–III activity in cerebral cortex. Creatine kinase activity was also inhibited by gentamicin administration. Simultaneous administration of MMA and gentamicin increased the activities of citrate synthase in cerebral cortex and kidney and complexes II–III in cerebral cortex. The other enzyme activities in cerebral cortex and kidney of animals receiving MMA plus gentamicin did not significantly differ from those observed in animals receiving only MMA. Our present data is line with the hypothesis that MMA acts as a toxin in brain and kidney of rats and suggest that renal injury potentiates the toxicity of MMA on the Krebs cycle and respiratory chain in brain and peripheral tissues.     

Considerations for ultra-endurance activities: part 1- nutrition

ABSTRACT

Ultra-endurance activities (≥ 4h) present unique challenges that, beyond fatigue, may be exacerbated by sub-optimal nutrition during periods of increased requirements and compromised gastrointestinal function. The causes of fatigue during ultra-endurance exercise are multi-factorial. However, mechanisms can potentially include central or peripheral fatigue, thermal stress, dehydration, and/or endogenous glycogen store depletion; of which optimising nutrition and hydration can partially attenuate. If exercise duration is long enough (e.g. ≥ 10h) and exercise intensity low enough (e.g. 45–60% of maximal oxygen uptake), it is bio-energetically plausible that ketogenic adaptation may enhance ultra-endurance performance, but this requires scientific substantiation. Conversely, the scientific literature has consistently demonstrated that daily dietary carbohydrates (3-12g/kg/day) and carbohydrate intake (30-110g/h) during ultra-endurance events can enhance performance at individually tolerable intake rates. Considering gastrointestinal symptoms are common in ultra-endurance activities, effective dietary prevention and management strategies may provide functional, histological, systemic, and symptomatic benefits. Taken together, a well-practiced and individualized fuelling approach is required to optimize performance in ultra-endurance events.     

机械通气患儿能量代谢特点和喂养状态研究

目的：通过间接测热法测定机械通气患儿静息能量消耗,研究其能量代谢特点和喂养状态,为改进营养支持策略提供依据。方法以2013年2月至2013年11月入住PICU,符合间接测热条件的37例机械通气患儿为研究对象,自符合测定条件起第1、4、7、10、14和21天测定静息能量消耗( measurement of resting energy expenditure,MREE),运用Schofield-HTWT公式计算预测静息能量消耗值( predicted resting energy expenditure,PREE),并统计每日热量摄入值。按MREE/PREE比值评定代谢状态：低代谢(<90％)、正常代谢(90％~110％)和高代谢(>110％)。按热量摄入值/MREE 比值评定喂养状态：喂养不足(<90％)、喂养适当(90％~110％)和喂养过度(>110％)。结果37例危重症儿童机械通气第1天,15例(40.5％)为低代谢,9例(24.3％)为正常代谢,13例(35.1％)为高代谢;机械通气第7天,呈高代谢状态患儿比例增加至46.7％,但较第1天无统计学差异(χ2＝0.516,P＝0.972)。营养支持应用率为81.1％;实施营养支持者,累计实施间接测热82次,每日热量摄入值为(33.4±22.2)kcal/(kg?d),显著低于MREE水平[(53.7±17.4)kcal/(kg?d)](t＝6.505,P<0.01)。在实施营养支持过程中,机械通气患儿有62 d(75.6％)喂养不足,8 d(9.8％)喂养适当,12 d(14.6％)喂养过度。结论 PICU滞留期间机械通气患儿能量代谢状态不断变化,且PICU滞留期间有近90％的时间里患儿喂养不达标。     

Neuroprotective effects of safflor yellow B on brain ischemic injury

The present study was conducted to investigate whether safflor yellow B (SYB) had a protective effect on cerebral ischemic injury and to determine the possible mechanisms in vivo and in vitro. In vivo, Male Wistar–Kyoto (WKY) rats were used to make the model of middle cerebral artery occlusion (MCAO). The behavioral test was used to measure neurological deficit scores for evaluation of the ischemic damage of brain. The infarction area of brain was assessed in brain slices stained with 2% solution of 2,3,5-triphenyl tetrazolium chloride (TTC). Spectrophotometric assay was used to determine the activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx), contents of malondialdehyde (MDA) and adenosine triphosphate (ATP) of the brain. Furthermore, the respiratory control ratio (RCR = state 3/state 4) was assessed in the brain mitochondria. In vitro, the effect of SYB was tested in cultured fetal cortical cells exposed to glutamate to identify its neuroprotection against neurons damage. The results in vivo showed that SYB at doses of 3.0 and 6.0 mg kg⁻¹ markedly decreased the neurological deficit scores and the infarction area in MCAO rats. At the same time, SYB significantly improved mitochondrial energy metabolism, decreased MDA content, and increased SOD and GPx activities in ischemic brain. The results in vitro showed that SYB remarkably inhibited neuron damage induced by glutamate in cultured fetal cortical cells. These suggest that SYB might act as a potential neuroprotective agent against the cerebral ischemia-induced injury in rat brain through reducing lipid peroxides, scavenging free radicals, and improving the energy metabolism.     

Changes in Energy Intake and Diet Quality during an 18-Month Weight-Management Randomized Controlled Trial in Adults with Intellectual and Developmental Disabilities

Background

Previous research indicates that individuals with intellectual and developmental disabilities (IDDs) are at risk for poor diet quality.