Determining energy costs of agricultural activities by respirometer and energy balance techniques

Differences of energy expenditure while sitting versus standing: A systematic review and meta-analysis

Background Replacing sitting with standing is one of several recommendations to decrease sedentary time and increase the daily energy expenditure, but the difference in energy expenditure between standing versus sitting has been controversial. This systematic review and meta-analysis aimed to determine this difference. Designs and methods We searched Ovid MEDLINE, Ovid Embase Scopus, Web of Science and Google Scholar for observational and experimental studies that compared the energy expenditure of standing versus sitting. We calculated mean differences and 95% confidence intervals using a random effects model. We conducted different predefined subgroup analyses based on characteristics of participants and study design. Results We identified 658 studies and included 46 studies with 1184 participants for the final analysis. The mean difference in energy expenditure between sitting and standing was 0.15 kcal/min (95% confidence interval (CI) 0.12-0.17). The difference among women was 0.1 kcal/min (95% CI 0.0-0.21), and was 0.19 kcal/min (95% CI 0.05-0.33) in men. Observational studies had a lower difference in energy expenditure (0.11 kcal/min, 95% CI 0.08-0.14) compared to randomised trials (0.2 kcal/min, 95% CI 0.12-0.28). By substituting sitting with standing for 6 hours/day, a 65 kg person will expend an additional 54 kcal/day. Assuming no increase in energy intake, this difference in energy expenditure would be translated into the energy content of about 2.5 kg of body fat mass in 1 year. Conclusions The substitution of sitting with standing could be a potential solution for a sedentary lifestyle to prevent weight gain in the long term. Future studies should aim to assess the effectiveness and feasibility of this strategy.

Posture Allocation Revisited: Breaking the Sedentary Threshold of Energy Expenditure for Obesity Management

There is increasing recognition that low-intensity physical activities of daily life play an important role in achieving energy balance and that their societal erosion through substitution with sedentary (mostly sitting) behaviors, whether occupational or for leisure, impact importantly on the obesity epidemic. This has generated considerable interest for better monitoring, characterizing, and promoting countermeasures to sedentariness through a plethora of low-level physical activities (e.g., active workstations, standing desks, sitting breaks), amid the contention that altering posture allocation (lying, sitting, standing) can modify energy expenditure to impact upon body weight regulation and health. In addressing this contention, this paper first revisits the past and more recent literature on postural energetics, with particular emphasis on potential determinants of the large inter-individual variability in the energy cost of standing and the impact of posture on fat oxidation. It subsequently analyses the available data pertaining to various strategies by which posture allocations, coupled with light physical activity, may increase energy expenditure beyond the sedentary threshold, and their relevance as potential targets for obesity management.

Measurement of human energy expenditure, with particular reference to field studies: an historical perspective

Over the years, techniques for the study of human movement have ranged in complexity and precision from direct observation of the subject through activity diaries, questionnaires, and recordings of body movement, to the measurement of physiological responses, studies of metabolism and indirect and direct calorimetry. This article reviews developments in each of these domains. Particular reference is made to their impact upon the continuing search for valid field estimates of activity patterns and energy expenditures, as required by the applied physiologist, ergonomist, sports scientist, nutritionist and epidemiologist. Early observers sought to improve productivity in demanding employment. Direct observation and filming of workers were supplemented by monitoring of heart rates, ventilation and oxygen consumption. Such methods still find application in ergonomics and sport, but many investigators are now interested in relationships between habitual physical activity and chronic disease. Even sophisticated questionnaires still do not provide valid information on the absolute energy expenditures associated with good health. Emphasis has thus shifted to use of sophisticated pedometer/accelerometers, sometimes combining their output with GPS and other data. Some modern pedometer/accelerometers perform well in the laboratory, but show substantial systematic errors relative to laboratory reference criteria such as the metabolism of doubly labeled water when assessing the varied activities of daily life. The challenge remains to develop activity monitors that are sufficiently inexpensive for field use, yet meet required accuracy standards. Possibly, measurements of oxygen consumption by portable respirometers may soon satisfy part of this need, although a need for valid longer term monitoring will remain.

INCAP Studies of Energy, Amino Acids, and Protein

This Special Issue summarizes the results of several studies aimed at providing information on a series of questions related to the adequate protein and energy intakes that allow adequate growth and function in children and work performance and productivity in adults. The effect of different sources of protein on nitrogen balance and the requirements of essential amino acids in young children were also explored in fully recovered, previously malnourished children housed in the Metabolic Ward of the Biomedical Division of INCAP.

The following are the main results of these investigations: » Animal experiments and studies in children recovering from protein–energy malnutrition (PEM) strongly suggest that even when requirements of all nutrients are satisfied, inactivity reduces the rate of linear growth and physical activity improves it as well as lean body mass repletion. » The effects of different energy intakes on nitrogen balance demonstrated how energy intake modifies the need to ingest different amounts of protein to satisfy protein requirements. » Insensible nitrogen losses in preschool children and their relation to protein intake was demonstrated. » The quality of even “good protein sources” modifies the amount needed to satisfy nitrogen requirements, and corn and bean-based diets can satisfy protein needs for health and even growth of young children. » Essential amino acid requirements of 2-year-old children was assessed by diverse measurements of nitrogen metabolism and amino acid levels in blood, and were found lower than those recommended by FAO-WHO. » In rural adult populations the relationship between energy and protein intake, productivity and body composition, and the impact of environmental hygiene on nitrogen balance was demonstrated and measured.

A compilation of energy costs of physical activities

OBJECTIVES

There were two objectives: first, to review the existing data on energy costs of specified activities in the light of the recommendations made by the Joint Food and Agriculture Organization/World Health Organization/United Nations University (FAO/WHO/UNU) Expert Consultation of 1985. Second, to compile existing data on the energy costs of physical activities for an updated annexure of the current Expert Consultation on Energy and Protein Requirements.

DESIGN

Electronic and manual search of the literature (predominantly English) to obtain published data on the energy costs of physical activities. The majority of the data prior to 1955 were obtained using an earlier compilation of Passmore and Durnin. Energy costs were expressed as physical activity ratio (PAR); the energy cost of the activity divided by either the measured or predicted basal metabolic rate (BMR).

RESULTS

The compilation provides PARs for an expanded range of activities that include general personal activities, transport, domestic chores, occupational activities, sports and other recreational activities for men and women, separately, where available. The present compilation is largely in agreement with the 1985 compilation, for activities that are common to both compilations.

CONCLUSIONS

The present compilation has been based on the need to provide data on adults for a wide spectrum of human activity. There are, however, lacunae in the available data for many activities, between genders, across age groups and in various physiological states.

Rural-to-urban migration and cardiovascular disease risk factors in young Guatemalan adults

BACKGROUND

Migration to cities may increase cardiovascular disease risk factors in developing countries. We examined rural and urban individuals who were born in the same villages and shared similar childhood experiences.

METHODS

Blood lipids and glucose, blood pressure, anthropometry, body composition, physical activity, and food, tobacco and alcohol consumption were examined in 161 men and 193 women, 19-29 years old, living in their village of birth (76 commuted to work in Guatemala City), and in 76 men and 43 women living in the city.

RESULTS

Rural and urban women had similar prevalence of overweight (28%), elevated body fat (29.8 +/- 6.1%) and low physical activity (83%). Compared to rural men, more urban men were sedentary (79 versus 27%), and they had higher body fat (15.3 +/- 5.3% versus 13.3 +/- 5.7%), serum cholesterol (4.27 +/- 0.75 versus 3.90 +/- 0.70 mmol/l [165 +/- 29 versus 151 +/- 27 mg/dl]), low density lipoprotein [LDL]-cholesterol (2.66 +/- 0.72 versus 2.30 +/- 0.62 mmol/l [103 +/- 28 versus 89 +/- 24 mg/dl]) and total cholesterol/high density lipoprotein [HDL]-cholesterol ratio (4.6 +/- 1.0 versus 4.1 +/- 0.9). Commuters showed intermediate values. Women had higher serum cholesterol (4.43 +/- 0.80 mmol/l [171 +/- 31 mg/dl]) than men in rural and urban areas. Urban residents ate/drank more saturated fats, red meat and sweetened beverages, and less legumes.

CONCLUSIONS

High proportions of young Guatemalan women were overweight and sedentary. Migration to a city increased sedentarism and undesirable eating habits among men and women; men became fatter and their lipid profile worsened. Public health actions must address the prevention of emerging chronic diseases in countries still burdened by undernutrition and infections.

Energy expenditure on household, childcare and occupational activities of women from urban poor households

This present study attempts to measure the energy cost of activities of women from the poor socio-economic group in India. Women in the age group of 18-40 years (n 98) either working for incomes or classified as homemakers were randomly selected. Time disposition studies were conducted by a 24 h observation of their activities on a typical day. Predominant activities were identified from the activity profiles and standardized for posture and duration. The BMR (Douglas bag method) and energy cost of the activities (Kofranyi-Michaelis meter) were measured by indirect calorimetry. The energy consumption during these activities ranged from 2.94-12.51 kJ/min. The tasks were divided into standard, household, childcare, occupational and other activities. Using the World Health Organization/Food and Agriculture Organization/United Nations University (1985) criteria, attempts were made to categorize the activities into light, moderate and heavy. It was significant that except for walking, the standard activities and occupational work could be classified into the light category (< 2.2 BMR). Most of the household and childcare activities except cooking were classified into the moderate to heavy (2.2-> 2.8 BMR). The energy expenditure of activities did not differ significantly between women with different occupations. This present study provides an important database on energy costs of activities for computing energy requirements of women involved in similar activity patterns.

Effect of spontaneous alcohol intake on heart rate and dietary intake of free-living women

Moderate alcohol consumers obtain excess calories from alcohol and these additional calories do not result in weight gain. This study examined the contribution of alcohol to the total caloric intakes and expenditures of light to moderate alcohol consumers and compared the data to soda drinkers. Physical activity levels were measured by employing continuous heart rate monitoring for a 6-day normal phase and a 6-day abstinence phase. The normal food intake of both groups was recorded in diet diaries. Subjects' overall intake of food energy during the alcohol week was significantly higher than during any of the other three phases (an excess of 241 kcal/day). This study suggests that excess alcohol calories are compensated by an increase in energy expenditure, as evidenced indirectly by increased heart rates occurring between the hours of 2300 and 0700 h, increased self-reported nightly restlessness, increased wake time, and exercise.

A new equation to predict the resting energy expenditure of surgical infants

It is essential that adequate calories are provided to newborns to cover their energy expenditure. This is difficult to measure and varies significantly between individuals. The aim of this study was to develop an equation to predict the basal energy requirements of stable surgical infants, using easily measurable parameters. Resting energy expenditure (REE) was measured using computerized open-circuit indirect calorimetry. One hundred twenty-two measurements were made on different days in 46 stable nonventilated infants. The measured REE was 34.41 +/- 0.46 cal/kg/min; (mean +/- SEM). Three body-size measurements correlated significantly with REE (cal/min): weight in kilograms (r = .87; P < .00001), body surface area in square meters (r = .86; P < .00001), and lean body mass in kilograms (r = .81; P < .00001). Five other independent variables correlated significantly with REE (cal/kg/min): heart rate in beats per minute (r = .60; P < .00001), postnatal age in days (r = .49; P < .00001) caloric intake in cal/kg/min (r = .44; P < .00001), gestational age in weeks (r = .43; P < .00001), and rectal temperature in degrees Celsius (r = .19; P = .04). Weight, heart rate, age, gestational age, and temperature were regarded as independent predictor variables of REE for the multiple stepwise regression analysis. Three variables entered this highly significant equation: REE (cal/min) = -74.436 + (34.661 x weight in kg) + (0.496 x heart rate in beats/min) + (0.178 x age in days) (r = .92; F = 230.07; significance, F < .00001).(ABSTRACT TRUNCATED AT 250 WORDS)

Energy intake, expenditure and pattern of daily activity of Nigerian male students

1. Twenty apparently healthy and normal Nigerian male students, resident at the University of Ibadan campus, were studied for seven consecutive days to assess their food energy intake and expenditure and pattern of their daily activities. 2. The mean age (years) of the group was 24.0 (SD 3.23, range 20-30), mean height (m) 1.71 (SD 0.06, range 1.61-1.84) and body-weight (kg) was 61.1 (SD 5.01, range 51.0-69.5). 3. The food intake of each subject was obtained by direct weighing and its energy value determined using a ballistic bomb calorimeter. Patterns of daily activities were recorded and the energy costs of representative activities were determined by indirect calorimetry. 4. Activities mainly involved sitting, mean 580 (SD 167, range 394-732) min/d. Sleeping and standing activities took a mean of 445 (SD 112) and 115 (SD 75) min/d respectively. Personal domestic activities took a mean of 94 (SD 40) min/d. 5. The mean energy intake of the group was 11,182 (SD 1970) kJ/d or 183 (SD 32) kJ/kg body-weight per d. This value is lower than the 12.5 MJ/d recommended by the Food and Agriculture Organization (FAO)/World Health Organization (WHO) (1973) as the energy requirement for an adult man engaged in moderate activities, but it is higher than the FAO/WHO/United Nations University (UNU) (1985) recommended value of 10.8 MJ/d for a male office clerk (light activity). It is also lower than the recommended energy requirement of 11.6 MJ/d for a subsistence farmer (moderately active work) (FAO/WHO/UNU, 1985). 6. The mean energy expenditure of the male subjects was 9876 (SD 1064, range 7159-12,259) kJ/d and was lower than mean intake. 7. The energy intake and expenditure values indicated that the groups participating in the present study were not physically very active. It is an indication that the Nigerian male students expended less but probably consumed more energy than required. It is suggested for health reasons and for mental fitness that the Nigerian male students might undertake more physical exercise.

Work tolerance and the elderly in a post-industrial society

The place of the elderly is reviewed in a society where automation is eliminating the demand for physical work. Physiological and social consequences are examined, drawing upon the experience of populations undergoing particularly rapid cultural change. It is argued that an increase of voluntary physical activity can correct many of the health problems arising in a post-industrial society, increasing both the quality and quantity of a worker's remaining years of life.