Intra-individual variation of basal metabolic rate and the influence of daily habitual physical activity before testing

Abstract

The present study determined the intra-individual variation of BMR measurements, using a standard out-patient protocol, with the subjects transporting themselves to the laboratory for the BMR measurements after spending the night at home. The effect of a non-fasting state and variation in daily habitual physical activity the day before testing was evaluated. Eight male and eleven female subjects participated in three BMR measurements with 2-week intervals. Physical activity was estimated with a tri-axial accelerometer for movement registration, during the 3 d before each BMR measurement. There were no significant differences in estimated BMR (ANOVA repeated measures, P¼0·88) and in physical activity (ANOVA repeated measures, P¼0·21). Mean within-subject CV in BMR was found to be 3·3 (SD 2·1) %, ranging from 0·4 to 7·2 %. Differences between BMR measurements could not be explained by differences in physical activity the day before; however the mean within-subject CV in BMR changed from 5·7 to 5·2 % after correcting for within-machine variability and from 5·2 to 3·3 % after excluding five measurements because of non-compliance to the protocol including fasting. In conclusion, BMR values measured with a standard out-patient protocol are sufficiently reproducible for most practical purposes despite the within-subject variability in physical activity the day before the measurement. For this purpose, however, non-fasting subjects must be excluded and a regular function check of the ventilated-hood system is recommendable. Reproducibility: Calorimetry: Body composition: AccelerometerBMR is the main component of average daily metabolic rate. It is defined as the daily rate of energy metabolism an individual needs to maintain and preserve the integrity of vital functions. A measurement of BMR must meet certain conditions. The subject must be awake and the measurement must be performed in a thermoneutral environment to avoid heat production or heat loss for maintenance of body temperature. Furthermore the subject must be in a fasted state (absence of diet-induced thermogenesis) and in rest (absence of activity-induced energy expenditure).Diet-induced thermogenesis is an increase in energy expenditure (EE) above BMR after eating. A 10 -12 h fast before BMR measurements is the accepted procedure followed by investigators to eliminate the thermic effect of food on basal EE. However, the time interval required to eliminate any residual effect of physical activity on BMR has not yet been described in a similar way. Some studies have observed that moderate-intensity physical activity elevates metabolic rate for only a few minutes to a few hours (Bahr et al.

Basal metabolic rate in the Yakut (Sakha) of Siberia

“…No repeat assessments of BMR were included in this study. However, previous studies have indicated that within-individual variation in BMR is typically less than 8%, although it is generally greater among women (Henry et al, 1989;Spurr et al, 1994;Adriaens et al, 2003).…”

Food Intake and Overweight in School-Aged Children in Germany: Results of the GINIplus and LISAplus Studies

“…A plausible energy intake reporter was defined as a child with 0.7 × TEI ≥ BMR. As the estimation of BMR and the cutoff used to differentiate underreporters and plausible energy intake reporters may not be entirely accurate [31], this variable was not included in the final models, but rather was used for descriptive and sensitivity analyses only.…”

Weight loss–induced reduction in physical activity recovers during weight maintenance

“…Gas analyses were performed with a paramagnetic oxygen analyzer (Servomex, type 1158) and an infrared carbon dioxide analyzer (Servomex, type 1520) while flow was kept at a constant rate of 80 L/min and additionally measured as described by Schoffelen et al (24). The withinindividual CV for this system is 3.3 6 2.1% (25). Calculation of RMR from measured oxygen consumption and carbon dioxide production was based on Brouwer's formula (26).…”