Physical activity as an indicator of predictive functional disability in elderly

To analyze the time spent on physical activity in female and male individuals as a predictor of the absence of functional disability in older adults, a cross-sectional study was conducted with 624 individuals. Receiver Operating Characteristic curves (ROC) were constructed and compared to areas of physical activity by gender and the absence of functional disability. We identified cutoffs of physical activity (minutes / week) to predict the absence of functional disability (CI 95%). It was found that there is a higher area under the ROC curve for the time spent on physical activities in females. It was observed that 280 minutes / week (women) or 410 minutes / week (men) were the best cutoff points for predicting the absence of functional disability. Time spent on physical activity practices can serve as an important indicator to sort priority groups for certain interventions.     

An assessment of caloric intake as an indicator of physical activity

Caloric intake has been suggested as a surrogate measure of physical activity, provided that energy balance is maintained. In this study we assessed caloric intake in relation to other measures of physical activity in a free-living population by a single 24-hr recall in white adult males, ages 22-79 years, examined in 1957-1960 as part of the U.S. Railroad Study. Intake was positively related to leisure time and occupational activity. Men with higher levels of caloric intake had lower exercise test heart rates indicating that they were probably more fit. Caloric intake was also significantly and inversely related to body mass index, the sum of the triceps and subscapular skinfold thickness measurements, blood pressure, and total serum cholesterol. These results suggest that caloric intake, even as measured in a 24-hr dietary recall, is an indicator of physical activity level. Therefore, caloric intake may be a useful indicator of physical activity in some population-based epidemiologic studies.     

Reliability of physical activity measures from accelerometry among preschoolers in free-living conditions

BACKGROUND & AIMS: Physical activity (PA) is a major determinant of obesity. Accelerometers have been reported to provide valid measures among adults. However, studies among preschoolers rarely report positive findings. To assess the day-to-day variability of accelerometers in preschoolers. METHODS: Uni-axial accelerometer (Actigraph monitor AM 7164-2.2) counts including one weekend from the time of getting up in the morning until bedtime. RESULTS: On average, boys showed 899 counts per minute (cpm) compared to 764 for girls (p<0.01; overall mean 828 cpm). Intra-individual correlation for accelerometry data between single days of examination was low with Pearson correlation coefficients between r=0.31 and 0.51. Furthermore, child's body mass index (BMI) and accelerometer measures were not related to each other (Pearson's correlation coefficient r=-0.06). Subsequent analyses showed higher measures (+50%cpm; p<0.01) for instruments placed in front of the umbilicus compared to instruments placed at the right hip. CONCLUSIONS: Measurements of uni-axial accelerometers showed a low reliability among preschoolers. Uni-axial accelerometers placed on elastic belts might measure PA with low precision among preschoolers under free-living conditions possibly due to slipping instruments. This might explain lacking findings of an association between PA and obesity in studies among preschoolers.     

Erythrocyte arginase activity as an indicator of lead exposure

ABSTRACT A semi-automated method has been developed for the determination of the arginase activity of erythrocytes using dried blood spots, which are easy to prepare on site in a factory for later laboratory analysis. The mean arginase activity of erythrocytes in 49 men occupationally exposed to lead was 62·9 IU/g·Hb (SD, 14·4 IU/g·Hb); in 45 men not exposed to lead the mean was 44·6 IU/g·Hb (SD, 11·6 IU/g·Hb). A significantly higher mean arginase activity was found in the specimens from lead-exposed workers (p < 0·001). The correlation coefficient between blood lead and erythrocyte arginase was r = 0·67 (p < 0·001). The degree of correlation between blood lead and lead indicators including arginase was r = 0·75 for urine δ-aminolaevulinic acid, r = 0·67 for erythrocyte arginase, r = 0·66 for urine lead, and r = 0·63 for coproporphyrin. Erythrocyte arginase showed no significant correlation in the liver function tests, GOT, GPT, and albumin in serum. When 40 μg/100 g of blood lead concentration was fixed as the basic value and 56·2 IU/g·Hb of erythrocyte arginase activity was set as the screening value in lead-exposed workers, the sensitivity and specificity of the arginase test were 0·96 and 0·65, respectively. Thus the validity of the test was calculated to be 1·61. These results show that the arginase level of erythrocytes can be considered to be one of the significant indicators of occupational exposure to lead because it reflects well the dose-response relationship of lead in the human body. Our method allows rapid analysis of erythrocyte arginase and thus should be useful in screening for lead exposure.     

Patterns of physical activity in free-living adults in the Southern United States

OBJECTIVE: To examine the relationship between the amount and patterns of physical activity (PA), body fatness, and age in a heterogeneous adult population in the free living. DESIGN: Cross-sectional study of the amount of PA over a 1-week period. The amount of body movements during PA (PA counts*10(3)) and time spent on various PA intensity categories were calculated from a triaxial accelerometer and compared with subject characteristics, including body fat from hydrodensitometry. PARTICIPANTS: Adult healthy men (n=48) and women (n=72) were recruited from the Nashville, Tennessee area and their PA was monitored in their free-living environment. RESULTS: The average weekday PA counts (176.5+/-60.3, P=0.002, r(2)=0.294), PA counts day-to-day variability (47.3+/-32.7, P=0.002, r(2)=0.286), daily maximum PA counts (241.9+/-89.2, P=0.001, r(2)=0.327), minute-to-minute variability on weekdays (0.281+/-0.091, P=0.001, r(2)=0.362), and the difference between maximum and minimum daily PA counts (130.6+/-78.3, P=0.008, r(2)=0.243) were significantly and negatively correlated with body fatness. During awake time, both men and women spent 10-12 h on low intensity (1.0-2.9 metabolic equivalents (METs)) PA, approximately 1 h on moderate (3.0-5.9 MET), and less than 10 min on vigorous (>6.0 MET) PA each day. On weekends, men and women spent more time at rest (1 MET), less time on low-intensity PA, and men spent more time on moderate PA than on weekdays. CONCLUSIONS: In adults living in the Southern US the amount of free-living PA was negatively correlated with body fatness. Both men and women spent the majority of active time on low and moderate PA. PA patterns on weekends were different than on weekdays and were related to sex and age, but not to body fatness. SPONSORSHIP: National Institutes of Health, US.     

Physical activity levels are low in free-living adults with chronic paraplegia

OBJECTIVES: To compare physical activity levels (PALs) of free-living adults with chronic paraplegia with World Health Organization recommendations and to compare energy expenditure between persons with complete vs. incomplete paraplegia. RESEARCH METHODS AND PROCEDURES: Twenty-seven euthyroid adults (17 men and 10 women) with paraplegia (12.5 +/- 9.5 years since onset; 17 with complete lesions and 10 with incomplete lesions) participated in this cross-sectional study. Resting metabolic rate was measured by indirect calorimetry and total daily energy expenditure (TDEE) by heart rate monitoring. PAL was calculated as TDEE/resting metabolic rate. Total body water was measured by deuterium dilution and fat-free mass (FFM) and fat mass (FM) by calculation (FFM = total body water/0.732; FM = weight - FFM). Obesity was defined using the following percentage FM cutoffs: men 18 to 40 years >22% and 41 to 60 years >25%; and women 18 to 40 years >35% and 41 to 60 years >38%. RESULTS: Nineteen subjects (70.4%; 13 men and six women) were obese. Fifteen subjects (56%) engaged in structured physical activity 1.46 +/- 0.85 times during the observation period for a mean of 49.4 +/- 31.0 minutes per session. Despite this, mean PAL of the group was 1.56 +/- 0.34, indicative of limited physical activity. TDEE was 24.6% lower in subjects with complete paraplegia (2072 +/- 505 vs. 2582 +/- 852 kcal/d, p = 0.0372). DISCUSSION: PAL of the group was low, indicating that persons with paraplegia need to engage in increased frequency, intensity, and/or duration of structured physical activity to achieve a PAL >/=1.75 and, thereby, to offset sedentary activities of daily living.     

Assessment of free-living physical activity in humans: an overview of currently available and proposed new measures

The number of physical activity measures and indexes used in the human literature is large and may result in some difficulty for the average investigator to choose the most appropriate measure. Accordingly, this review is intended to provide information on the utility and limitations of the various measures. Its primary focus is the objective assessment of free-living physical activity in humans based on physiological and biomechanical methods. The physical activity measures have been classified into three categories: Measures based on energy expenditure or oxygen uptake, such as activity energy expenditure, activity-related time equivalent, physical activity level, physical activity ratio, metabolic equivalent, and a new index of potential interest, daytime physical activity level. Measures based on heart rate monitoring, such as net heart rate, physical activity ratio heart rate, physical activity level heart rate, activity-related time equivalent, and daytime physical activity level heart rate. Measures based on whole-body accelerometry (counts/U time). Quantification of the velocity and duration of displacement in outdoor conditions by satellites using the Differential Global Positioning System may constitute a surrogate for physical activity, because walking is the primary activity of man in free-living conditions. A general outline of the measures and indexes described above is presented in tabular form, along with their respective definition, usual applications, advantages, and shortcomings. A practical example is given with typical values in obese and non-obese subjects. The various factors to be considered in the selection of physical activity methods include experimental goals, sample size, budget, cultural and social/environmental factors, physical burden for the subject, and statistical factors, such as accuracy and precision. It is concluded that no single current technique is able to quantify all aspects of physical activity under free-living conditions, requiring the use of complementary methods. In the future, physical activity sensors, which are of low-cost, small-sized, and convenient for subjects, investigators, and clinicians, are needed to reliably monitor, during extended periods in free-living situations, small changes in movements and grade as well as duration and intensity of typical physical activities.     

Measuring free-living energy expenditure and physical activity with triaxial accelerometry

OBJECTIVE: To investigate the ability of a newly developed triaxial accelerometer to predict total energy expenditure (EE) (TEE) and activity-related EE (AEE) in free-living conditions. RESEARCH METHODS AND PROCEDURES: Subjects were 29 healthy subjects between the ages of 18 and 40. The Triaxial Accelerometer for Movement Registration (Tracmor) was worn for 15 consecutive days. Tracmor output was defined as activity counts per day (ACD) for the sum of all three axes or each axis separately (ACD-X, ACD-Y, ACD-Z). TEE was measured with the doubly labeled water technique. Sleeping metabolic rate (SMR) was measured during an overnight stay in a respiration chamber. The physical activity level was calculated as TEE x SMR(-1), and AEE was calculated as [(0.9 x TEE) - SMR]. Body composition was calculated from body weight, body volume, and total body water using Siri's three-compartment model. RESULTS: Age, height, body mass, and ACD explained 83% of the variation in TEE [standard error of estimate (SEE) = 1.00 MJ/d] and 81% of the variation in AEE (SEE = 0.70 MJ/d). The partial correlations for ACD were 0.73 (p < 0.001) and 0.79 (p < 0.001) with TEE and AEE, respectively. When data on SMR or body composition were used with ACD, the explained variation in TEE was 90% (SEE = 0.74 and 0.77 MJ/d, respectively). The increase in the explained variation using three axes instead of one axis (vertical) was 5% (p < 0.05). DISCUSSION: The correlations between Tracmor output and EE measures are the highest reported so far. To measure daily life activities, the use of triaxial accelerometry seems beneficial to uniaxial.     

Validity of mutagenic activity as an indicator of river water pollution

Objectives To investigate if mutagenicity could be expressed by known water pollution indicators, we determined the mutagenic activity of blue rayon extracts from sampled river water with the Ames test utilizing new strains of bacteria, and compared the results with those of known indicators of water pollution. Methods Water samples were collected by the blue rayon adsorption method at sixteen sites in six rivers in the North Kyushu district. The Assay of mutagenicity was carried out using the Ames test. The test strains wereSalmonella typhimurium TA100, YG1024, YG1041 and YG1042. B(a)P, Trp-P-1 and Trp-P-2 were quantified by HPLC. Determinations of SS, BOD, COD, T-N, T-P, DOC, and A₂₆₀/DOC were performed. Results The extracts from five sampling sites showed higher mutagenicity toward strain YG1024 with or without S9mix, and the extracts from two of these five sites showed higher mutagenicity toward strain YG1041 with and without S9mix. However, the water pollution indicators did not show specific trends that were consistent with the mutagenic activity. Conclusions Since the mutagenic activity of river water could not be predicted using known water pollution indicators, we recommend that biological examinations such as mutagenicity tests be added to the indicators that are currently in use.     

Physical activity and social status in adolescence as predictors of physical inactivity in adulthood

BACKGROUND: Physical inactivity is related to an increased risk of certain chronic diseases. The aim here was to evaluate how physical activity and social status in adolescence are associated with physical inactivity in adulthood. METHODS: The sample comprised 3664 males and 4130 females who answered questions on physical activity and social status at 14 and 31 years of age in follow-up surveys of the Northern Finland birth cohort of 1966. Associations between explanatory factors and physical inactivity in adulthood were analyzed using multivariable logistic regression. RESULTS: Infrequent participation in sports after school hours at 14 years of age and, in males, additionally a low grade in school sports, was associated with physical inactivity at the age of 31 years, independent of social circumstances in adulthood. Low social class of the childhood family was associated with physical inactivity in adolescence but not with inactivity at 31 years of age. Poor school achievement in adolescence was associated with adult inactivity independent of adolescent physical activity. CONCLUSION: Infrequent participation in sports, a low grade in school sports, and poor school achievements in adolescence were associated with physical inactivity in adulthood. Participation in sports is to be strongly supported among all adolescents because of its long-term beneficial effects on adult health through its tendency to reduce the probability of adult inactivity.     

Relation of body composition to daily physical activity in free-living Japanese adult women

The objective of the present study was to investigate the relationship between the indices of body size such as BMI, fat-free mass index (FFMI, FFM/height2), fat mass index (FMI, FM/height2), and body fat percentage (%BF), and physical activities assessed by the doubly-labelled water (DLW) method and an accelerometer in free-living Japanese adult women. We conducted a cross-sectional study in 100 female subjects ranging in age from 31 to 69 years. Subjects were classified in quartiles of BMI, FFMI, FMI and %BF. Daily walking steps and the duration of light to vigorous physical activity were simultaneously assessed by an accelerometer for the same period as the DLW experiment. Only physical activity-related energy expenditure (PAEE)/FFM and PAEE/body weight (BW) decreased in the highest quartile of BMI. Physical activity level, PAEE/FFM and PAEE/BW decreased in the highest quartile of FMI and %BF, whereas they were not different among quartiles of FFMI. Daily walking steps and the duration of moderate- and vigorous-intensity physical activities decreased or tended to decrease in the highest quartile of FMI and %BF, but did not differ among quartiles of FFMI and BMI. These results clearly showed that Japanese adult women with higher fat deposition obviously had a low level of physical activities assessed by both the DLW method and accelerometry, but those with larger BMI had lower PAEE/FFM and PAEE/BW only. Our data suggest that the relationship between obesity and daily physical activities should be discussed using not only BMI but also FMI or %BF.     

The effects of shift work on free-living physical activity and sedentary behavior

ObjectiveAlthough occupation may influence physical activity and shift work schedule may influence cardiovascular disease risk factors, our understanding of the effects of shift work schedule on overall physical activity behavior and sedentary behavior is limited.MethodsData from the 2005–2006 National Health and Nutrition Examination Survey were used. Shift work schedule was defined as regular daytime shift, evening, night, rotating or another schedule. Physical activity and sedentary behavior were assessed via accelerometry. 1536 adult participants (≥ 20 years) indicated they currently work and provided data on all study variables.ResultsAfter adjustments, and compared to adults working a regular daytime shift, those working an evening (RR = 0.41, p = 0.001) and night (RR = 0.30, p = 0.001) shift, respectively, engaged in 59% and 70% less sustained (bouts) moderate-to-vigorous physical activity, but no differences occurred for overall moderate-to-vigorous physical activity. After adjustments, and compared to those working a regular daytime shift, those working a rotating shift engaged in more light-intensity physical activity (overall: β = 26.3 min/day; p = 0.03; bouts: β = 37.5, p = 0.01) and less sedentary behavior (β = − 28.5 min/day, p = 0.01).ConclusionsShift work schedule differentially influences physical activity and sedentary behavior. Physical activity and sedentary intervention strategies may need to be tailored based on shift work schedule.     

Reliable method to estimate characteristics of sleep and physical inactivity in free-living conditions using accelerometry

PURPOSE: The purpose of this study is to use a new method to assess the characteristics of sleep and diurnal physical inactivity in human beings by means of accelerometry, noninvasively and in free-living conditions. METHODS: Forty girls and 40 boys aged 13 to 15 years, randomly selected from rural Senegal, wore an accelerometer for a 72-hour period during the dry season in 1998 and 2000. An algorithm already tested in another study was used to objectively calculate the characteristics of sleep and physical inactivity from movement registration provided by accelerometry. RESULTS: Adolescent girls slept for a longer time and more quietly than adolescent boys (8 hours 45 minutes versus 8 hours 9 minutes). Girls were more inactive than boys (4 hours 23 minutes versus 2 hours 49 minutes). Reliability estimates of physical inactivity period measures were excellent (0.74 to 0.78), and those of sleep period and length measures were acceptable (0.45 to 0.61). Girls and boys had the same levels of reliability, except for sleep efficiency measures. CONCLUSIONS: These findings could be explained by the nature and sex division of habitual tasks within the community. The accelerometer is a valid and useful epidemiologic tool for measuring characteristics of sleep and physical inactivity in free-living conditions. This innovative tool opens new prospects in epidemiology and public health, especially in the worldwide epidemic of chronic diseases associated with physical inactivity and sleep disorders.     

Leisure-time physical activity as an estimate of physical fitness: a validation study

This paper describes a new interview questionnaire for the assessment of leisure-time physical activity (LTPA), and its validation as an alternative estimate of physical fitness. British subjects (77 males, 41 females) provided details of their LTPA over a period of a "typical" 2 weeks, enabling the estimation of the energy expended. Physical fitness was assessed with a battery of measures, the optimal single measure being sub-maximal physical work capacity (PWC). The questionnaire showed LTPA to be stable following test-retest administration (r = 0.86; p less than 0.0001) for total LTPA energy expenditure. Total LTPA was found to be significantly related to PWC (r = 0.48, p less than 0.0001), as were very hard (r = 0.55; p less than 0.0001) and hard LTPA (r = 0.38; p less than 0.0001). Multiple regression analysis with PWC as the dependent variable yielded a multiple correlation of r = 0.87, with significant contributions from very hard and hard LTPA. It is concluded that whilst this questionnaire is both reliable and a valid estimate of physical fitness amongst a population consistent in their leisure-time physical activities, there is scope for its further use within larger populations, allowing for an analysis of the effects of age and gender on the associations so far observed.     

Supervised and free-living physical activity: no differences in former athletes and nonathletes

The association of past participation in school sports with present physical activity was studied in 265 Caucasian men who represented a broad spectrum of cardiovascular health. In cross-sectional and prospective analyses of free-living and supervised settings, no differences in contemporary adult activity were observed between former athletes and nonathletes (p greater than .05). Statistical control for selection bias effects by age, body mass index, sum of skin folds, exercise tolerance, and coronary health status did not alter the results. Recall of free-living physical activity was verified by significant (p less than .05) correlations with a concurrent self-report of activity and with body mass index and exercise tolerance adjusted for coronary health status. Previous reports of an association between school sports participation and adult activity have failed to control for subject selection bias and confounding variables, verify activity recall, and examine both supervised and free-living environments. Although these data do not support the role of youthful sports participation in adult physical activity, future studies could provide objective measures of school and community sports participation and subjective measures of the sports experience in relation to other sex, race, and ethnic factors.     

Physical activity level in healthy free-living Japanese estimated by doubly labelled water method and International Physical Activity Questionnaire

OBJECTIVE: To measure total energy expenditure (TEE) for normal healthy Japanese by the doubly labelled water (DLW), and to compare the physical activity level (PAL) among categories classified by the categories used in daily reference intake (DRI), Japan and the International Physical Activity Questionnaire (IPAQ). SUBJECTS AND METHODS: A total of 150 healthy Japanese men and women aged 20- to 59-year-old living in four districts of Japan. TEE was measured by the DLW method, and the PAL was calculated from TEE divided by basal metabolic rate. Simultaneously with TEE measurement, the PAL was assessed employing the categories used in DRI, Japan and IPAQ. RESULTS: The average TEE and PAL were 10.78+/-1.67 MJ/day and 1.72+/-0.22 for males and 8.37+/-1.30 MJ/day and 1.72+/-0.27 for females, respectively. The subjects in the highly active categories assessed by both DRI and IPAQ showed significantly higher PAL compared with less active categories. However, PALs among light and moderate categories by DRI, and insufficient and sufficiently active by IPAQ were not significantly different. CONCLUSIONS: In developed countries, highly active subjects could be assessed by a simple questionnaire. However, the questionnaire should be improved to clarify the sedentary to moderately active subjects by assessing carefully very light to moderate physical activity.     

Biological age as an integral indicator of the impact of working conditions on workers' health

The integral health indices (biological age, age-related individual physiological features during a long-term (during a shift) contact with occupational allergens and working factors, the body's wear rates, and functional adaptive processes under hazardous working conditions) were studied in workers having dangerous jobs.     

Physical activity as leisure: the meaning of physical activity for the health and well-being of adolescent women

Globally, low participation in physical activity by adolescent young women is a major health concern. While the barriers to activity for this group are well documented, little is known about the views and experiences of nonathlete, but active, young women. In order to gain an understanding of young women's lived experiences of the relationship between physical activity as leisure and health, data were collected through focus groups. Active nonathlete young women in the United Kingdom attached significant meaning to physical activity as a space for leisure, and used it to enhance their health and well-being.