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Low resting metabolic rate is associated with greater lifespan because of a confounding effect of body fatness.

Duarte LC, Speakman JR - Age (Dordr) (2014)

Bottom Line: Fat-free mass (FFM) and fat mass (FM) were both significantly positively related to RMR.After removing the effect of FFM on RMR, the association between RMR and lifespan remained significantly negative; however, after statistically removing the effect of FM on RMR, the significant association between RMR and lifespan disappeared.We conclude that the negative association between RMR and lifespan is primarily due to the effect of FM, with FM positively related to both RMR and mortality and hence RMR negatively to lifespan.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, Scotland, AB24 2TZ, UK, l.duarte@abdn.ac.uk.

ABSTRACT
A negative association between resting metabolic rate (RMR) and lifespan is the cornerstone of the rate of living and free-radical damage theories of aging. Empirical studies supporting a negative association of RMR to lifespan may arise from the correlation between RMR and both daily energy expenditure (DEE) and thermoregulatory activity energy expenditure (TAEE). We screened 540 female mice for higher and lower DEE and measured RMR in the resulting 324 (60 %). We then selected 92 mice in which there was no link between residual from the regression of RMR against body mass (BM) and residual of DEE against BM to separate the effects of these traits. Lifespan was not significantly related to body mass, DEE and TAEE, but significantly negatively related to RMR. Fat-free mass (FFM) and fat mass (FM) were both significantly positively related to RMR. After removing the effect of FFM on RMR, the association between RMR and lifespan remained significantly negative; however, after statistically removing the effect of FM on RMR, the significant association between RMR and lifespan disappeared. We conclude that the negative association between RMR and lifespan is primarily due to the effect of FM, with FM positively related to both RMR and mortality and hence RMR negatively to lifespan. In 40 additional screened mice, greater FM was also associated with greater oxidative damage to DNA.

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Related in: MedlinePlus

Steps followed for mice screening and the respective sample size in each step
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Related In: Results  -  Collection


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Fig1: Steps followed for mice screening and the respective sample size in each step

Mentions: Our aim in this work was to screen a large population of mice for aspects of their energy balance and then select from this population a subset where the covariances between components of balance were not significant. The overall selection process is summarised by the flow diagram in Fig. 1 (detailed material and methods available as electronic supplementary material—ESM).Fig. 1


Low resting metabolic rate is associated with greater lifespan because of a confounding effect of body fatness.

Duarte LC, Speakman JR - Age (Dordr) (2014)

Steps followed for mice screening and the respective sample size in each step
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4262579&req=5

Fig1: Steps followed for mice screening and the respective sample size in each step
Mentions: Our aim in this work was to screen a large population of mice for aspects of their energy balance and then select from this population a subset where the covariances between components of balance were not significant. The overall selection process is summarised by the flow diagram in Fig. 1 (detailed material and methods available as electronic supplementary material—ESM).Fig. 1

Bottom Line: Fat-free mass (FFM) and fat mass (FM) were both significantly positively related to RMR.After removing the effect of FFM on RMR, the association between RMR and lifespan remained significantly negative; however, after statistically removing the effect of FM on RMR, the significant association between RMR and lifespan disappeared.We conclude that the negative association between RMR and lifespan is primarily due to the effect of FM, with FM positively related to both RMR and mortality and hence RMR negatively to lifespan.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, Scotland, AB24 2TZ, UK, l.duarte@abdn.ac.uk.

ABSTRACT
A negative association between resting metabolic rate (RMR) and lifespan is the cornerstone of the rate of living and free-radical damage theories of aging. Empirical studies supporting a negative association of RMR to lifespan may arise from the correlation between RMR and both daily energy expenditure (DEE) and thermoregulatory activity energy expenditure (TAEE). We screened 540 female mice for higher and lower DEE and measured RMR in the resulting 324 (60 %). We then selected 92 mice in which there was no link between residual from the regression of RMR against body mass (BM) and residual of DEE against BM to separate the effects of these traits. Lifespan was not significantly related to body mass, DEE and TAEE, but significantly negatively related to RMR. Fat-free mass (FFM) and fat mass (FM) were both significantly positively related to RMR. After removing the effect of FFM on RMR, the association between RMR and lifespan remained significantly negative; however, after statistically removing the effect of FM on RMR, the significant association between RMR and lifespan disappeared. We conclude that the negative association between RMR and lifespan is primarily due to the effect of FM, with FM positively related to both RMR and mortality and hence RMR negatively to lifespan. In 40 additional screened mice, greater FM was also associated with greater oxidative damage to DNA.

Show MeSH
Related in: MedlinePlus