身体运动加速度与运动量测量的关系研究

直接或间接卡路里计所根据的原理是热动力学；用加速度计来测量身体运动能量消耗的原理是牛顿力学定律。从运动学的角度来说：定量测量身体能量消耗，首先应考虑用加速度计的方法来测量。先以身体活动及能量消耗为依据来定义身体运动量。很明显，所有的身体活动都依赖于肌肉收缩，以热量耗散和对外做功的形式消耗能量。身体活动具有动力学的性质，同时人在承受重量的过程中还具有静力学的性质。大量的经验数据表明：身体加速度绝对值对时间的积分与能量消耗或耗氧量成线性关系。因此，如果能忽略肌肉在承受重量过程中的能量消耗，就可以认为身体加速度绝对值对时间的积分即代表能量消耗。     

中国儿童青少年体力活动量表的信效度研究

目的检验儿童青少年身体活动量表的信度及效度。方法采用随机分层整群抽样,对南京市城区3所学校401名学生进行研究。使用加速度传感器对6~18岁儿童青少年进行身体活动7d跟踪监测,并在第8天完成一份儿童青少年身体活动量表。采用Cronbach’α系数对身体活动量表的信度进行评价;通过加速度传感器得到的客观身体活动量与问卷结果计算出的身体活动水平之间的Spearman相关系数评价儿童青少年身体活动量表的效度。结果身体活动量表结果与加速度传感器测量的每天中高强度身体活动(MVPA)之间的Spearman相关系数为0.31,男生(r=0.35)明显高于女生(r=0.24),上学日(r=0.34)明显高于周末日(r=0.22)。身体活动量表所测中等强度身体活动(MPA)、高强度身体活动(VPA)和MVPA的Cronbach’sα系数分别为0.56、0.67和0.73(P均0.01)。结论该量表用于测量中国儿童青少年身体活动水平的信度是可以接受的,但效度依然不高。未来应针对如何提高该问卷的效度做进一步的修改和验证。     

频率自适应起搏器的运动一心率预测系统的研究

从基于加速度传感器的体动型频率自适应起搏器心率控制方法的研究入手．设计了一种运动一心率预测系统。系统的上位机和下位机之间通过蓝牙模块进行通讯。下位机完成人体加速度信号的采集、处理以及加速度信号向起搏心率信号的映射．同时完成加速度信号和心率信号的实时传输。上位机完成人体加速度信号和心率信号的实时显示和记录．并且通过对6个参数的分级设置实现对下位机的算法控制。应用运动一心率预测系统进行的验证实验结果表明．线性算法得到的映射起搏心率和实际心率的相关性比较好,线性比较显著（R2=O．787,P〈O．001）。     

基于无线传感器的患者运动信号检测系统设计及其应用

目的：为了实时获取患者的运动生理信号,设计基于无线三轴加速度传感器的人体运动信息检测系统,并初步将运动信息用于简单的单自由度人机交互,可用于患者的自主康复训练。方法：通过给患者穿戴嵌有三轴加速度传感器的节点,节点集成有射频芯片和低功耗单片机,可以实时采集患者的运动加速度信息。无线基站负责接受无线信号,再将信号通过RS232串口协议发送到计算机进行更复杂的数据处理。计算机对信号进行去噪预处理,并提取时域特征量进行非常规的人机交互。结果：该系统的节点设计轻巧,穿戴舒适,成功地采集帕金森患者行走运动加速度信号并且信号的有效传输距离可以覆盖整个病房。信号去噪处理能够有效抑制各类噪声干扰,交互控制设计能够很好地识别头部运动方向,进行正确的人机交互控制。结论：无线传感器能够在低负荷,非视频下检测患者的运动信息,而其捕获的运动信息可广泛运用于各种临床领域。     

智能手机的运动量干预软件的研制

目的 研制了一款基于智能手机的运动管理软件,对佩戴者进行运动量的行为干预.方法 采用android系统的手机,通过调用智能手机自带的加速度传感器来识别运动状态,进行佩戴者的活动量检测,同时将运动信息上传健康管理中心.结果 实现了系统功能,通过健康管理中心的信息反馈提示对佩戴者开展行为学干预,指导佩戴者科学安全地进行身体锻炼,达到最有效最合适的锻炼效果.结论 基于手机智能平台的行为干预可作为行为治疗的一种新手段.     

问卷调查与运动手环测量少年儿童身体活动的相关性分析

目的 探讨研制的“中国6～17岁儿童身体活动问卷”与运动手环测量儿童身体活动的相关性。方法 在北京市延庆区和重庆市万州区选取4所学校6个班级共120名学生参与调查。采用Spearman等级相关方法和BlandAltman方法检验问卷与运动手环测量身体活动时间的相关性，运用广义多元线性回归方法建立校正模型，提高问卷测量的准确性。结果 问卷调查与运动手环测量总体身体活动时间的相关系数（r）为0.38 (P<0.001)，测量中等及以上强度身体活动时间的r为0.22～0.32 (P<0.019)。建立的总体身体活动时间、中高强度身体活动时间和身体活动能量消耗的校正模型可分别解释45.1%、41.4%和46.9%运动手环测量的总变异。结论 问卷调查与运动手环测量我国6～17岁少年儿童身体活动的相关性低。使用校正模型可以提高问卷测量的准确性。     

基于手机的血压无线监测系统研制及初步应用

研制一种新型的手机型血压无线监测系统．包括一个以硬件为主的血压测量信号采集端,以及可将血压测量振荡波法所需的两路信号以蓝牙方式发送至本系统的另一部分——手机软件接收端,实现血压和心率的计算以及所测波形的实时绘制、显示和存储等功能。通过与商用血压测量仪器的对比实验,验证了系统的可靠性与稳定性,并开展了一系列新颖的探究性实验,如不同时段人体血压的波动、身体姿态对血压测量值的影响以及运动改变血压的状况等。     

人体总能量消耗测量方法研究进展

人体总能量消耗(total energy expenditure,TEE)是指在个体或群体水平上一段时间内平均每天的能量消耗量[1],成人的TEE主要包括基础代谢、身体活动和食物热效应.测量人体TEE对于制定适宜的能量需要量,进而维持最佳的健康状况和身体机能至关重要.     

人体运动量测量与心率变化的重要关系研究

身体的活动作为人类行为的重要部分和人类的健康和疾病状况有着一定的关系。人在每天的日常生活中要进行各种活动，在活动过程中，通过摄取物质而得到的能量又以热量和做功的形式消耗出去。对于不同的人和不同的运动量，能量消耗的程度也不一样。人在运动过程中，心率会随着运动量的变化而变化，心率变化和运动量的测量之间有着非常密切的关系，本文通过一些实验研究来叙述他们之间的重要关系，并提出了Holter系统中加入运动量测量功能的设想。     

基于iOS的老年人跌倒检测报警系统研究

目的:设计一种基于手机的老年人跌倒检测报警系统,为跌倒后的老人提供及时的帮助,争取更多的急救时间.方法:利用iPhone内置的三轴加速度传感器和陀螺仪提取人体加速度和角速度数据,计算与人体运动相关的特征值信号向量幅值(signal vector magnitude,SVM)、信号幅值面积(signal magnitude area,SMA)、倾斜角(tilt angle,TA),采用多阈值判断算法判别人体是否发生跌倒.发生跌倒时,手机向监护人发出跌倒报警.结果:在系统准确性检测实验中,模拟老年人行走、慢跑、坐下、躺下、弯腰及前向跌倒、侧向跌倒、后向跌倒.慢跑识别准确率为96％,出现错报;前向跌倒检测准确率为98％,出现漏报;其余准确率皆为100％,系统正确率为99.25％.结论:该系统可直接利用手机内置传感器有效检测跌倒,并且对手机的放置方位无要求,是一种易于接受且更为可行的跌倒检测系统.     

Impacts of vigorous and non-vigorous activity on daily energy expenditure

Activity intensity is a potential determinant of activity-induced energy expenditure. Tri-axial accelerometery is the most objective measurement technique for the assessment of activity intensity, in combination with doubly-labelled water for the measurement of energy expenditure under free-living conditions. Data on the effects of subject characteristics, including body size and age, and exercise training on the relationship between activity intensity and daily energy expenditure are reviewed. Average daily metabolic rate and non-basal energy expenditure are positively related to body size. The duration and intensity of physical activities do not need to be equivalent to the energy spent on activity. Obese subjects spend more energy on physical activity but can perform fewer activities, especially high-intensity (weight-bearing) activities, because of their higher body weight. Physical activity generally declines gradually from about 60 years of age onwards. Most subjects > 80 years have an activity level well below the level defined for sedentary middle-aged adults. Spending relatively more time on low-intensity activities has a negative effect on the mean physical activity level. To obtain a higher physical activity level does not necessarily imply high-intensity activities. In an average subject 25% of the activity-induced energy expenditure may be attributed to high-intensity activities. Exercise training, as a form of high-intensity activity, affects the physical activity level more in younger subjects than in elderly subjects.     

Adjusted body weight, con: why adjust body weight in energy-expenditure calculations?

Evaluation of energy requirements of normal individuals and hospitalized patients is most often accomplished using an energy equation. Energy equations attempt to measure resting metabolic rate (RMR), the largest factor in total daily energy expenditure. Components of most energy equations include height, weight, age, and gender. These factors are related to energy expenditure; however, each factor has individual characteristics that affect energy expenditure. Body weight is a major factor in RMR and total daily energy expenditure. For obese individuals, estimation of energy expenditure may be a challenge due to the increased body weight. Therefore, some equations attempt to minimize the effect of body weight on energy expenditure assessment by adjusting the obese individual's body weight. Data do not support adjustment of body weight in normal individuals. In hospitalized patients, there are several equations that are used to estimate energy expenditure of obese patients, which include adjusting the body weight and modifying the overall energy requirements. Measurement of RMR can obviate the need for estimating energy expenditure. It is important to evaluate any energy-expenditure equation that is used to estimate energy needs in normal people and hospitalized patients before applying it to patient care.     

Energy intake, energy expenditure, and smoking in relation to body fatness: the Zutphen Study

In 1965 within the Zutphen Study information on several possible determinants of body fatness (eg, energy intake, energy expenditure, alcohol intake, coffee consumption, tea consumption, and smoking) was collected. Univariate analyses showed that for 525 men aged 45-64 y and free from cardiovascular diseases, indicators of body fatness were inversely related to the difference between energy intake and expenditure, physical activity per kilogram body weight, smoking, and coffee consumption. Alcohol intake was directly related to Quetelet index, and tea consumption was not related to indicators of body fatness. Inverse associations between indicators of body fatness and the difference between energy intake and expenditure, physical activity per kilogram body weight, and smoking were confirmed in multivariate analyses. The inverse association between body fatness and the difference between energy intake and expenditure may be due to the underestimation of energy intake by obese subjects. In lean people this association may be explained by a thermogenic effect of smoking.     

Diet induced thermogenesis

OBJECTIVE: Daily energy expenditure consists of three components: basal metabolic rate, diet-induced thermogenesis and the energy cost of physical activity. Here, data on diet-induced thermogenesis are reviewed in relation to measuring conditions and characteristics of the diet. METHODS: Measuring conditions include nutritional status of the subject, physical activity and duration of the observation. Diet characteristics are energy content and macronutrient composition. RESULTS: Most studies measure diet-induced thermogenesis as the increase in energy expenditure above basal metabolic rate. Generally, the hierarchy in macronutrient oxidation in the postprandial state is reflected similarly in diet-induced thermogenesis, with the sequence alcohol, protein, carbohydrate, and fat. A mixed diet consumed at energy balance results in a diet induced energy expenditure of 5 to 15 % of daily energy expenditure. Values are higher at a relatively high protein and alcohol consumption and lower at a high fat consumption. Protein induced thermogenesis has an important effect on satiety.In conclusion, the main determinants of diet-induced thermogenesis are the energy content and the protein- and alcohol fraction of the diet. Protein plays a key role in body weight regulation through satiety related to diet-induced thermogenesis.     

Resting energy expenditure and substrate utilisation rate in children with constitutional leanness or obesity

BACKGROUND & AIM: The influence of energy expenditure on body weight regulation, in the absence of organic disease, has never been studied in a paediatric population covering a broad range of body weights. The aim of this study was to investigate resting energy metabolism in children with constitutional leanness, normal body weight, or common obesity. METHODS: Fourteen children with constitutional leanness, 16 children with obesity, and controls were studied. Resting energy expenditure and postabsorptive substrate utilisation rate were measured by indirect calorimetry and body composition was assessed from skinfold thicknesses. RESULTS: As compared to the predicted value calculated from the regression equation of resting energy expenditure on fat-free mass in the controls, resting energy expenditure was decreased in lean children (P=0.002), whereas no difference was found in obese children. In obese children and the overall population, fat mass was positively correlated with fat oxidation rate. In each group and in the overall population, fat oxidation rate was positively correlated to resting energy expenditure. CONCLUSIONS: Constitutionally lean children have a low resting metabolic rate, probably adaptive in nature. In obese children, resting energy expenditure is increased in proportion to the fat-free mass, and fat balance is the main determinant of energy balance. These data suggest a constitutional regulation of body weight.     

Metabolic consequences of overfeeding in humans

PURPOSE OF REVIEW: Overfeeding leads to obesity and metabolic disorders, including impaired glucose homeostasis, lipid disorders, and hepatic steatosis. The consequences of standardized overfeeding on body weight have shown, however, considerable interindividual variability, which suggests that it also leads to adaptative changes in energy expenditure, in some individuals at least. The present review is mainly focused on the recent developments regarding the effects of overfeeding on energy expenditure. RECENT FINDINGS: Individuals who gain the less body weight during overfeeding are those who experience a greater increase in total energy expenditure. This increase in energy expenditure has been attributed to stimulation of nonexercise physical activity. Recent developments regarding adaptative increases in physical activity are critically reviewed. Overfeeding also alters the pathways used for carbohydrate storage after a glucose load, by increasing de-novo lipogenesis in the liver and adipose tissue at the expense of glycogen storage. The sympathetic nervous system is a good candidate for energy expenditure increase during overfeeding. The increases in energy expenditure observed during acute stimulation of the sympathetic nervous system were however found to be unaltered by short-term overfeeding. SUMMARY: The mechanisms by which some individuals protect themselves against body weight gain remain poorly understood. Nonvoluntary physical activity may allow one to increase energy expenditure during overfeeding, and may therefore constitute a regulatory factor in body weight control. The biological determinant of spontaneous, nonvoluntary physical activity, however, remains to be investigated.     

An objective measure of physical activity for epidemiologic research.

The development of a device is reported called the Large-scale integrated Motor Activity Monitor to examine physical activity during individuals' normal daily lives. The unit which is slightly larger than a wrist watch records body movement when worn at various body locations. Two population studies were conducted to evaluate the units. Experiment 1 examined 20 male graduate students for a two-day period. The data indicated that the units were sensitive to individual differences in physical activity and did not interfere with normal activities. Experiment 2 compared 10 Physical Education majors with 10 non-Physical Education majors by having individuals log activities and record movement counts for a two-day period. The movement data revealed that the monitors significantly discriminated between the two populations. The energy expenditure derived from the specific loggings was highly related (r = +.69) to the trunk movements, indicating that the movement counts are an accurate estimate of physical activity. The high relationship to energy analysis, the sensitivity of the units and the ease of implementation indicate that the units may be useful in relating normal activity to acute heart disease and to risk factors such as obesity and lipoproteins.     

Self-Directed Weight Loss Strategies: Energy Expenditure Due to Physical Activity Is Not Increased to Achieve Intended Weight Loss

Reduced physical activity and almost unlimited availability of food are major contributors to the development of obesity. With the decline of strenuous work, energy expenditure due to spontaneous physical activity has attracted increasing attention. Our aim was to assess changes in energy expenditure, physical activity patterns and nutritional habits in obese subjects aiming at self-directed weight loss. Methods: Energy expenditure and physical activity patterns were measured with a portable armband device. Nutritional habits were assessed with a food frequency questionnaire. Results: Data on weight development, energy expenditure, physical activity patterns and nutritional habits were obtained for 105 patients over a six-month period from an initial cohort of 160 outpatients aiming at weight loss. Mean weight loss was −1.5 ± 7.0 kg (p = 0.028). Patients with weight maintenance (n = 75), with substantial weight loss (>5% body weight, n = 20) and with substantial weight gain (>5% body weight, n = 10) did not differ in regard to changes of body weight adjusted energy expenditure components (total energy expenditure: −0.2 kcal/kg/day; non-exercise activity thermogenesis: −0.3 kcal/kg/day; exercise-related activity thermogenesis (EAT): −0.2 kcal/kg/day) or patterns of physical activity (duration of EAT: −2 min/day; steps/day: −156; metabolic equivalent unchanged) measured objectively with a portable armband device. Self-reported consumption frequency of unfavorable food decreased significantly (p = 0.019) over the six-month period. Conclusions: An increase in energy expenditure or changes of physical activity patterns (objectively assessed with a portable armband device) are not employed by obese subjects to achieve self-directed weight loss. However, modified nutritional habits could be detected with the use of a food frequency questionnaire.     

Does body mass play a role in the regulation of food intake?

It is widely believed that body fatness (and hence total body mass) is regulated by a lipostatic feedback system. This system is suggested to involve at least one peripheral signalling compound, which signals to the brain the current size of body fat stores. In the brain the level of the signal is compared with a desirable target level, and food intake and energy expenditure are then regulated to effect changes in the size of body fat stores. There is considerable support for this theory at several different levels of investigation. Patterns of body-mass change in subjects forced into energy imbalance seem to demonstrate homeostasis, and long-term changes in body mass are minor compared with the potential changes that might result from energy imbalance. Molecular studies of signalling compounds have suggested a putative lipostatic signal (leptin) and a complex network of downstream processing events in the brain, polymorphisms of which lead to disruption of body-mass regulation. This network of neuropeptides provides a rich seam of potential pharmaceutical targets for the control of obesity. Despite this consistent explanation for the observed phenomena at several different levels of enquiry, there are alternative explanations. In the present paper we explore the possibility that the existence of lipostatic regulation of body fatness is an illusion generated by the links between body mass and energy expenditure and responses to energy imbalance that are independent of body mass. Using computer-based models of temporal patterns in energy balance we show that common patterns of change in body mass following perturbation can be adequately explained by this 'non-lipostatic' model. This model has some important implications for the interpretations that we place on the molecular events in the brain, and ultimately in the search for pharmaceutical agents for alleviation of obesity.     

Energy Metabolism in Relation to Diet and Physical Activity: A South Asian Perspective

The prevalence of overweight and obesity is on the rise around the world, not only in the West, but also in Asian countries. South Asian countries in particular are experiencing a rapid increase in overweight and obesity, that coexists with the rapid increase in non-communicable diseases linked to obesity such as diabetes and cardiovascular disease than any other country in Asia. The phenomena observed in South Asian countries are due to the size of the population, the ageing of the population, the high degree of urbanization and the lifestyle changes in favor of increased energy consumption and reduced physical activity. The imbalance between energy consumption and energy expenditure results in the development of a positive energy balance that, over time, accumulates in higher body fat. South Asians were reported to have a more unfavorable body composition with a higher percentage of body fat than Caucasians with an equivalent BMI. Body composition is a major determinant of resting energy expenditure. It has been reported that South Asians have a lower resting energy expenditure than Caucasians with the same BMI. Resting energy expenditure accounts for the majority of total daily energy expenditure and, therefore, plays a crucial role in achieving the balance between energy intake and expenditure.