Endotherms maintain high and constant body temperatures through the production and maintenance of metabolic heat. Defining the evolutionary history of these thermal adaptations and the selective factors responsible for the evolution of endothermy despite its high metabolic costs have been elusive and controversial topics in evolutionary biology. In this sense, several models have been proposed ...

The molecular basis for variations in resting metabolic rate (RMR) within a species is unknown. One possibility is that variations in RMR occur because of variations in uncoupling protein 2 (UCP-2) and uncoupling protein 3 (UCP-3) expression, resulting in mitochondrial proton leak differences. We tested the hypothesis that UCP-2 and -3 mRNAs positively correlate with RMR and proton leak. We tre...

The 'membrane pacemaker' hypothesis provides a putative mechanistic linkage between variations in energy metabolism, rates of ageing and lifespan across different species. Within species we have found positive associations between longevity and metabolism, which contrast the inter-specific trends. It is of interest to know therefore how levels of lipid desaturation in membranes are linked to va...

The purpose of this study was to assess the validity and reliability of the MedGem device to measure resting metabolic rate (RMR) in children. Subjects included 59 children (29 boys, 30 girls; mean age, 11.0 +/- 0.2 y). Subjects were given 4 RMR tests during 1 test session, cconsisting of 2 Douglas bag and 2 MedGem tests, in random counterbalanced order. No significant differences were found be...

Objective This study looks at the risks associated with subclinical hypothyroidism and a new management paradigm that optimizes thyroid function based on Resting Metabolic Rate (RMR) and Brachioradialis Reflexometry (BR). Main Outcome Brachioradialis Reflexometry (BR) correlates the best with RMR measurements and, in this population, seems to be the best parameter to titrate thyroid dose. Using...

This study examined gender differences in resting metabolic rate (RMR) across a broad age spectrum after controlling for differences in body composition and aerobic fitness. Three hundred twenty-eight healthy men (17-80 yr) and 194 women (18-81 yr) volunteers were characterized for RMR, body composition, physical activity, peak oxygen consumption (peak VO2), anthropometrics, and energy intake. ...

Leptin contributes to the control of resting metabolic rate (RMR) and blood pressure (BP) through its actions in the arcuate nucleus (ARC). The renin-angiotensin system (RAS) and angiotensin AT1 receptors within the brain are also involved in the control of RMR and BP, but whether this regulation overlaps with leptin's actions is unclear. Here, we have demonstrated the selective requirement of ...

We examined the effect of pretesting environment on measurement of resting metabolic rate (RMR). RMR was measured in 18 older (66.1 +/- 1.4 y) individuals after an overnight stay in the Clinical Research Center (ie, inpatient) and after subjects transported themselves to the laboratory (ie, outpatient). Similar measurements were also performed after an 8-wk endurance-training program. RMR was h...

OBJECTIVE This study examined the repeatability of measuring resting metabolic rate (RMR) in preschool children and the effect of different calculation protocols. RESEARCH METHODS AND PROCEDURES Eleven children (4 females and 7 males) participated in the project. They were recruited through advertisements in local schools and community centers. Resting metabolic rate was measured on 3 occasio...

OBJECTIVE To study whether or not the amount of vitamin A consumed affects the resting metabolic rate (RMR) and fat oxidation at rest in severely obese subjects. MATERIALS AND METHODS In 239 obese subjects, RMR and fasting respiratory quotient (RQ) were determined by indirect calorimetry. Vitamin A consumption was calculated by the Czech PC program 'Nutrition'. The relation between the intake...