A. Leon

Compendium of physical activities: an update of activity codes and MET intensities.

We provide an updated version of the Compendium of Physical Activities, a coding scheme that classifies specific physical activity (PA) by rate of energy expenditure. It was developed to enhance the comparability of results across studies using self-reports of PA. The Compendium coding scheme links a five-digit code that describes physical activities by major headings (e.g., occupation, transportation, etc.) and specific activities within each major heading with its intensity, defined as the ratio of work metabolic rate to a standard resting metabolic rate (MET). Energy expenditure in MET-minutes, MET-hours, kcal, or kcal per kilogram body weight can be estimated for specific activities by type or MET intensity. Additions to the Compendium were obtained from studies describing daily PA patterns of adults and studies measuring the energy cost of specific physical activities in field settings. The updated version includes two new major headings of volunteer and religious activities, extends the number of specific activities from 477 to 605, and provides updated MET intensity levels for selected activities.

Physical activity and body weight : associations over ten years in the CARDIA study

BACKGROUND: Hypothesis 1—sustained changes in physical activity are inversely related to changes in body weight. Hypothesis 2—those who attenuate weight gain because of a temporary increase in physical activity (PA) may maintain a lower body weight over time.METHODS: Data were from the Coronary Artery Risk Development in Young Adults (CARDIA) Study, a cohort of black and white men and women, aged 18–30u2005y at baseline, who attended up to five examinations over a 10u2005y period (n=5115 at baseline). Longitudinal associations between physical activity and body weight changes were assessed, adjusting for secular trend, age, clinic site, education, smoking, alcohol intake, parity, percentage energy intake from fat, and changes in these variables over time. For hypothesis 1, concurrent associations of physical activity and body weight changes were examined. For hypothesis 2, we explored whether weight gain attenuation associated with increased PA during the initial 2–3u2005y of follow-up was sustained over 5u2005y. The study 2 analyses were conducted with three separate 5u2005y intervals: baseline to year 5 (n=3641), years 2–7 (n=3160), and years 5–10 (n=2617).RESULTS: Hypothesis 1—change in physical activity was inversely associated with change in body weight within all four race and sex sub-groups (P<0.005). The predicted weight change associated with change in physical activity was four to five times larger in participants who were overweight compared with those who were not were overweight at baseline. Hypothesis 2—an increase in physical activity during 2–3u2005y of follow-up was associated with an attenuation of weight gain that was sustained through 5u2005y of follow-up whether or not the physical activity increase was maintained during the later years. This finding persisted whether the starting point for the 5u2005y follow-up was year 2, year 5 or baseline (women only). Comparing participants who increased physical activity with those who decreased physical activity in the first 2–3u2005y of follow-up (eg by at least 2u2005h per week of stationary cycling for at least 6 months per year), the mean 5u2005y weight gain attenuation ranged from 0.8 to 2.8u2005kg.CONCLUSIONS: The results of these analyses support the need for public health messages for promoting increased physical activity for weight maintenance and attenuation of age-related weight gain, especially for higher weight sub-populations.

INTRA-INDIVIDUAL VARIATION IN ESTIMATES OF USUAL PHYSICAL ACTIVITY

PURPOSEnThe magnitude of intra-individual variation, as determined by three methods of physical activity (PA) assessment, was estimated to determine the optimal number of repeated measures needed to reliably measure an individuals usual PA habits.nnnMETHODSnData were obtained from 77 healthy adults enrolled in the Survey of Activity, Fitness, and Exercise (SAFE). PA was measured by: 1) Caltrac accelerometers worn 48-hours every 26 days for one year; 2) concurrent 48-hour PA records (PARs); and 3) a corresponding series of four-week PA histories (FWH). Repeated measures regression analyses were used to analyze the data.nnnRESULTSnPA tended to be slightly higher in the summer months as compared with the winter months, but this seasonality explained little of the intra-individual variation. The intra-individual standard deviation (SD) estimated for the FWH (180 MET-min(d(-1))) was 39% of the mean annual MET-min(d(-1)), as compared with the Caltrac (163 MET-mind(d(-1)) or 9%) and PAR (259 MET-min(d(-1)) or 11%). Given the intra-individual variation, three repeated observations of the FWH, six Caltrac, or nine PAR over the course of the year were needed to achieve 80% reliability in estimation of mean annual PA.nnnCONCLUSIONSnIntra-individual variation in PA is substantial and must be accounted for in estimates of usual PA.