Independent effects of diet and exercise training on fat oxidation in non-alcoholic fatty liver disease

AIM To investigate the independent effects of 6-mo of dietary energy restriction or exercise training on wholebody and hepatic fat oxidation of patients with nonalcoholic fatty liver disease(NAFLD).METHODS Participants were randomised into either circuit exercise training(EX;n = 13;3 h/wk without changes in dietary habits),or dietary energy restriction(ER) without changes in structured physical activity(ER;n = 8).Respiratory quotient(RQ) and whole-body fat oxidation rates(Fatox) were determined by indirect calorimetry under basal,insulin-stimulated and exercise conditions.Severity of disease and steatosis was determined by liver histology;hepatic Fatox was estimated from plasma β-hydroxybutyrate co.ncentrations;cardiorespiratory fitness was expressed as VO2 peak.Complete-case analysis was performed(EX:n = 10;ER:n = 6).RESULTS Hepatic steatosis and NAFLD activity score decreased with ER but not with EX.β-hydroxybutyrate concentrations increased significantly in response to ER(0.08 ± 0.02 mmol/L vs 0.12 ± 0.04 mmol/L,P = 0.03) but remained unchanged in response to EX(0.10 ± 0.03 mmol/L vs 0.11 ± 0.07 mmol/L,P = 0.39).Basal RQ decreased(P = 0.05) in response.to EX,while this change was not significant after ER(P = 0.38).VO_(2peak)(P < 0.001) and maximal Fa_(tox) during aerobic exercise(P = 0.03) improved with EX but not with ER(P > 0.05).The increase in β-hydroxybutyrate concentrations was correlated with the reduction in hepatic steatosis(r =-0.56,P = 0.04).CONCLUSION ER and EX lead to specific benefits on fat metabolism of patients with NAFLD.Increased hepatic Fat_(ox) in response to ER could be one mechanism through which the ER group achieved reduction in steatosis.

The effects of fluid loss on physical performance： A critical review

目的:对现有的关于研究水合状态对运动员身体活动能力影响的证据进行批判性分析。方法:从多个数据库检索获取符合纳入标准的文献,随后采用唐斯和布莱克协议(Downs and Black protocol)对纳入文献进行批判性评估。结果:9篇文章符合入选标准,平均79%在方法论质量上代表高标准的研究。结论:证据表明在持续30s以上的活动中,脱水状态在身体表现中有消极作用:然而在少于15 s的持续运动中,脱水状态对身体表现并无显著影响。

Relationship Between Metabolic Fitness and Performance in Police Occupational Tasks

Purpose To determine the relationship between metabolic fitness test scores and performance in police occupational tasks.Methods Retrospective data from 106 law enforcement officers who completed two metabolic fitness assessments[anaerobic:a 20-m (10-m and 20-m splits) sprint,aerobic:20 m Multi-Stage Fitness Test (20 m-MSFT)]and three routine occupational tasks[1.22 m Fence jump (FJ),8.5 m Victim Drag (VD with 102.3 kg) and "Get-up" (GU)]were collected.A Person's cor-relation coefficient and a standard multiple regression were used to assess the relationship between and predictive ability of,respectively,the fitness tests scores and performance on occupational tasks.Results There was a significant positive correlation between the 10-m sprint scores and FJ (r=0.524,P<0.001),VD(r =0.528,P < 0.001) and GU (r=0.486,P < 0.001).Similarly,the 20-m sprint scores were significantly and moderately correlated with FJ (r=0.573,P < 0.001),VD (r=0.603,P < 0.001) and GU (r=0.533,P < 0.001).These anaerobic tests' scores predicted approximately 40% of the performance in the occupational tasks analysed.The MSFT fitness assessment had a small,albeit significant negative correlation with the three tasks:FJ (r=-0.360,P< 0.001),VD (r=-0.266,P=0.012)and GU (r=-0.375,P< 0.001).Conclusion High levels of metabolic fitness correlated with faster performance in police officer occupational tasks,particu-larly ones of an anaerobic nature (i.e.the maximal sprint tests).In addition to typical aerobic fitness conditioning,anaerobic fitness conditioning could be vital for optimal performance in physically demanding tasks required of police officer.