Higher Energy Expenditure in Humans Predicts Natural Mortality
ABSTRACT Higher metabolic rates increase free radical formation, which may accelerate aging and lead to early mortality.
Our objective was to determine whether higher metabolic rates measured by two different methods predict early natural mortality in humans.
Nondiabetic healthy Pima Indian volunteers (n = 652) were admitted to an inpatient unit for approximately 7 d as part of a longitudinal study of obesity and diabetes risk factors. Vital status of study participants was determined through December 31, 2006. Twenty-four-hour energy expenditure (24EE) was measured in 508 individuals, resting metabolic rate (RMR) was measured in 384 individuals, and 240 underwent both measurements on separate days. Data for 24EE were collected in a respiratory chamber between 1985 and 2006 with a mean (SD) follow-up time of 11.1 (6.5) yr and for RMR using an open-circuit respiratory hood system between 1982 and 2006 with a mean follow-up time of 15.4 (6.3) yr. Cox regression models were used to test the effect of EE on natural mortality, controlled for age, sex, and body weight.
In both groups, 27 natural deaths occurred during the study period. For each 100-kcal/24 h increase in EE, the risk of natural mortality increased by 1.29 (95% confidence interval = 1.00-1.66; P < 0.05) in the 24EE group and by 1.25 (95% confidence interval = 1.01-1.55; P < 0.05) in the RMR group, after adjustment for age, sex, and body weight in proportional hazard analyses.
Higher metabolic rates as reflected by 24EE or RMR predict early natural mortality, indicating that higher energy turnover may accelerate aging in humans.
Full-textDOI: · Available from: Reiner Jumpertz-von Schwartzenberg, Jan 29, 2014
SourceAvailable from: Jennifer A Schrack[Show abstract] [Hide abstract]
ABSTRACT: Objectives To assess the associations among age, health status, and resting metabolic rate (RMR) in a large population of older adults.DesignCross-sectional analysis.SettingCommunity-dwelling volunteers from the Baltimore Longitudinal Study of Aging (BLSA).ParticipantsPersons aged 40 to 96 (mean 68.2 ± 11.0) who underwent a comprehensive physical examination, cognitive assessment, RMR testing, body composition assessment, and physical function testing during a 3-day clinic visit (N = 420).MeasurementsParticipants were assigned to Insight into the Determination of Exceptional Aging and Longevity (IDEAL) or non-IDEAL categories based on health status. IDEAL participants were defined according to the absence of physical and cognitive impairments, chronic conditions and comorbidities, and blood profile abnormalities. A three-stage linear regression model was used to assess the relationship between RMR and age, using IDEAL classification as a predictor and adjusting for sex and body composition.ResultsResting metabolic rate averaged 1,512.4 ± 442.9 kcal/d and was lower with older age (β = −8.55, P < .001). After adjusting for age, sex, and body composition, RMR was 109.6 kcal/d lower in IDEAL than non-IDEAL participants (P < .005).Conclusion Individuals who are fully functional and free of major medical conditions have lower RMR than those with disease and functional impairments. These findings suggest that health status plays a role in energy use and regulation independent of age and body composition and that elevated RMR may be a global biomarker of poor health in older persons.Journal of the American Geriatrics Society 03/2014; 62(4). DOI:10.1111/jgs.12740 · 4.22 Impact Factor
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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.Journal of the American Aging Association 12/2014; 36(6):9731. DOI:10.1007/s11357-014-9731-3 · 3.45 Impact Factor
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ABSTRACT: Stress places a metabolic burden on homeostasis and is linked to heightened sympathetic activity, increased energy expenditure and pathology. The yogic state is a hypometabolic state that corresponds with mind-body coherence and reduced stress. This study aimed to investigate metabolic responses to stress and different yoga practices in regular yoga practitioners (YP), non-yoga practitioners (NY) and metabolic syndrome patients (MS).BMC Complementary and Alternative Medicine 11/2014; 14(1):445. DOI:10.1186/1472-6882-14-445 · 1.88 Impact Factor