Participation in organised sports does not slow declines in physical activity during adolescence

Background  

Among youth, participation in extracurricular physical activities at school and organised physical activities in the community is associated with higher physical activity levels. The objective was to determine if participation in organised physical activities during early adolescence protects against declines in physical activity levels during adolescence.     

Physical activity, physical fitness and coronary disease

The relationship between physical activity on and off the job, physical fitness and coronary artery disease was investigated in a prospective study involving 2 363 men, 40 to 55 years old. Sudden death and myocardial infarction occurred in 31 subjects during a 5-year follow-up. Preliminary data are reported. There was no significant correlation between quartiles of physical activity on and off the job and incidence of coronary events. Physical fitness was significantly inversely correlated with incidence of coronary events (p less than 0.05) and was significantly lower in the 31 new cases (p less than 0.03). Multivariate analysis showed that HDL-cholesterol, smoking and physical fitness significantly and independently discriminate between coronary prone patients and healthy subjects. We conclude that physical fitness is an independent, inverse risk indicator of new coronary events.     

Admission electronic fetal monitoring does not improve neonatal outcomes

Admission electronic fetal monitoring did not decrease neonatal morbidity and mortality compared with intermittent auscultation. Patients in the admission fetal monitoring group were more likely to receive continuous electronic monitoring and fetal blood sampling, but there were no significant differences in the rates of operative deliveries or episiotomy. Institutions not routinely using admission electronic fetal monitoring should not start; those that do may not be benefiting their patients.     

Leisure-time physical activity does not fully explain the higher body mass index in irregular-shift workers

Purpose

To elucidate the influence of leisure-time physical activity on body mass index (BMI), appetite-related hormones, and sleep when working irregular shifts.

Methods

A cross-sectional study was undertaken of 57 male truck drivers, 31 irregular-shift workers and 26 day-shift workers. Participants completed the International Physical Activity Questionnaire and were assessed for BMI. Subjects also provided a fasting blood sample for analysis of appetite-related hormones and wore an actigraphy device for seven consecutive days.

Results

Although leisure-time physical activity (LTPA) was generally low (<150 min/week) in both groups, the irregular-shift workers were more physically active than day-shift workers (99 ± 166 vs. 23 ± 76 min/week, p < 0.01). In spite of this, mean BMI of irregular-shift workers was 2 kg/m² greater than day-shift workers (28.4 ± 3.8 vs. 26.4 ± 3.6 kg/m², p = 0.04). Mean leptin concentration was 61 % higher in irregular-shift workers (5,205 ± 4,181 vs. 3,179 ± 2,413 pg/ml, p = 0.04). Among obese individuals, irregular-shift workers had higher leptin concentration (p < 0.01) and shorter sleep duration (p = 0.01) than obese day-shift workers.

Conclusion

Elevated BMI was associated with high leptin and low ghrelin levels in this population of irregular-shift workers. No influence of LTPA on appetite-related hormones or sleep duration was found. We conclude that moderate LTPA is insufficient to attenuate the higher BMI associated with this type of irregular-shift work in truck drivers.     

Increased nerve growth factor by zinc supplementation with concurrent vitamin A deficiency does not improve memory performance in mice

We investigated the effects of dietary supplementation of zinc (Zn) with or without vitamin A (Vit. A), to elucidate any cross activity between the two micronutrients, on memory and nerve growth factor (NGF) production in ddY male mice depleted for the two elements. After 3 mo-feeding with a Zn and Vit. A deficient (VAD) diet, mice were divided into three groups and replenished with normal Zn with VAD diet (NZ-VAD), high Zn with VAD diet (HZ-VAD) or normal Zn + normal Vit. A (NZ-NVA) for additional 2 mo. One more group was made and given the normal diet for the same period (Control group). Levels of NGF were measured from extracts of hippocampus, cerebellum and cortex at the end of the 3rd and 5th month. In addition, a radial arm maze task was performed at the end of the 5th month. The two Zn supplemented groups (NZ-VAD and HZ-VAD) tended to show high NGF concentration but memory was not improved. However, improved memory was observed in the NZ-NVA group. From these results we concluded that Zn may increase NGF; however, memory was improved only when Vit. A was sufficient.     

Objectively assessed physical activity,fitness and subjective wellbeing

BackgroundThe existing evidence for a cross-sectional association between physical activity and subjective wellbeing is inconsistent, mainly because of the reliance on self reported physical activity, which might have conceptual overlap with subjective health.PurposeTo examine associations of objectively assessed physical activity and cardiorespiratory fitness with subjective wellbeing.MethodsA sub-sample of participants (921 men and women, mean age 44.6 ± 15.0 yrs, 46.4% men) from the 2008 Health Survey for England completed objective measures of physical activity (Actigraph) and an 8 min sub-maximal step test to estimate levels of cardiorespiratory fitness. The General Health Questionnaire and self-rated health was used as indicators of subjective wellbeing.ResultsThe recorded levels of moderate to vigorous physical activity (MVPA) were higher in participants reporting very good health (adjusted mean difference = 6.7, 95% CI, 1.1–12.4 min/d, p = 0.019) compared with participants reporting fair–poor health after adjustment for various confounders and fitness level. Neither physical fitness, objectively assessed sedentary time or light activity was related to self-rated health. There was also no association between objectively measured physical activity and fitness with psychological health, despite a robust association with self reported MVPA in the overall sample.ConclusionsObjectively assessed MVPA is independently associated with self-rated health. Self reported, but not objectively assessed MVPA, was associated with psychological health. The null findings with regards to psychological health might partly reflect selection biases associated with the healthy nature of this sub-sample of participants.     

Lifetime occupational physical activity and prostate cancer risk

The authors compared the lifetime occupational physical activity of 452 prostate cancer cases identified through the population-based Hawaii Tumor Registry and 899 population controls interviewed from 1981 to 1983. Each job reported was classified into one of five levels of physical activity using published sources. Among men aged 70 years or older, a negative association was found between prostate cancer risk and proportion of life spent in jobs involving only sedentary or light work. Compared with men never employed in such jobs, men who spent more than 54% of their life in these jobs had an odds ratio of 0.5 (95% confidence interval 0.3-0.9). This negative association was dose-dependent, consistent across ethnic groups, and unrelated to socioeconomic status, dietary risk factors, or job-related chemical exposures. The findings for younger men were less clear, but not inconsistent with those for older men. Surprisingly, no association was found with years spent in moderately active or very active jobs in either age group. Although inconclusive, these results suggest that physical activity may be positively associated with the risk of prostate cancer, but this association is likely to be weak and indirect.     

Conjugated linoleic acid does not improve insulin tolerance in mice

OBJECTIVE: To determine if the addition or removal of dietary conjugated linoleic acid (CLA) would alter insulin tolerances in mice from two genetic lines. RESEARCH METHODS AND PROCEDURES: High metabolic rate (MH) and low metabolic rate (ML) mice were assigned to consume 1) a control diet ad libitum, 2) a control diet at a restricted intake, or 3) a diet containing 1% CLA ad libitum. After 9 weeks, an insulin tolerance test was conducted, and a portion of the mice were killed. All remaining mice consumed the control diet ad libitum. Insulin tolerance tests were conducted 11 and 32 days after the diet change, and mice were killed 3 days after each test. Body fatness, fat pad weights, and serum insulin concentrations of mice were determined at each time-point. Two follow-up experiments were also conducted. RESULTS: Restricted mice had insulin sensitivities not different than control mice. CLA-fed MH mice in experiment 1 were resistant (p < 0.001) to insulin on each day measured. CLA-fed ML mice were slightly resistant (p = 0.08) to exogenous insulin on day 0 of recovery and not different from control mice on day 11 or 32. Glucose response to insulin in MH mice fed CLA in experiments 2 or 3 did not differ from control mice. DISCUSSION: Mice fed CLA did not have improved insulin tolerances compared with control mice. In some cases, dietary CLA may cause insulin resistance. MH mice seem more sensitive to CLA than ML mice.     

体育锻炼家庭支持性环境对中小学生身体素质的影响

分析2014年10~18岁学生体育锻炼家庭支持性环境对身体素质的影响,为指导家长提高学生身体素质提供依据.方法 利用2014年“全国学生体质与健康调研”体能测试资料,包括50 m跑、耐力跑、立定跳远、握力、引体向上/仰卧起坐、坐位体前屈共6项体能测试指标,按照年龄、性别进行标准化,计算Z评分,比较不同家庭支持性环境下学生身体素质的差异.结果 学生体育锻炼活动家庭支持环境中,不支持率男生高于女生(10.94%和8.69%),乡村学生高于城市学生(10.78%和8.85%);10~12岁年龄段学生不支持率最高,为10.42%,高于13~ 15岁(9.78%)和16~ 18岁年龄段(9.09%);中部地区学生不支持率最高,为10.68%,高于东部(8.87%)和西部(10.15%),差异均有统计学意义(X2值分别为247.98,183.22,59.37,112.51,P值均<0.05).体育锻炼活动家庭支持环境中的学生握力、短跑和耐力跑、立定跳远、仰卧起坐、坐位体前屈等Z评分均优于不支持的中学生,在不同性别、年龄段、地区学生中均呈现相同的趋势.结论 体育锻炼家庭支持性环境对学生的身体素质有积极作用,家长应支持学生进行体育锻炼.     

中国儿童青少年体力活动与体能指数的相关性

目的 分析中国儿童青少年体力活动(PA)与体能指数(PFI)的相关性,为改善中国儿童青少年体力活动水平以及提升体能素质提供参考.方法 于2018年9-12月采用整群抽样方式在华东、西北、华北、华中、西南和华南区选取4269名7～18岁学生,收集体力活动等数据,并完成立定跳远、握力、50 m跑、改良坐位体前屈、30 s仰...